MAPSview Instrument Descriptions

For each instrument in the MAPS project, you'll find an overview, a detailed description of the instrument, detailed descriptions of the Key Parameter data it collects and links to the Cassini pages for that instrument. Keep in mind:


Cassini CAPS home: http://caps.space.swri.edu/

The Cassini Plasma Spectrometer Subsystem (CAPS) measures the flux of ions as a function of mass per charge and the flux of ions and electrons as a function of energy per charge and angle of arrival relative to the CAPS instrument. The CAPS Subsystem consists of three major instruments: the ion mass spectrometer, the ion beam spectrometer and the electron spectrometer.

The ion mass spectrometer (IMS) provides species-resolved measurements of the flux of positively charged atomic and molecular ions as a function of energy/charge vs aperture entry direction. The IMS uses a toroidal top-hat electrostatic analyzer combined with a linear electric field time-of-flight mass spectrometer (for mass/charge and other species-resolving data).

The second major CAPS instrument is the ion beam spectrometer (IBS). The IBS measures the flux of positively charged ions of all species as a function of energy/charge and aperture entry direction. The IBS based on a hemispherical electrostatic analyzer.

The third major CAPS sub-instrument is the electron spectrometer (ELS), which measures the flux of electrons as a function of energy/charge and aperture entry direction.

An important subassembly of CAPS is the actuator (ACT). The ACT rotates the CAPS instrument at a steady rate over a maximum range of 184 degrees with the acceleration/deceleration over a further 12 degrees (minimum) at either end of this range.

The CAPS Key Parameter data set consists of four different files. (1) MOMT: which contains calculated moments of the ion and electron distributions including ion density, velocity, pressure and electron density and temperature. In addition the file includes error estimates. (2) SPEC: this file includes energy spectra data for ions (3) EPSC: electron energy spectra (4) PADS: finally, this file contains information about the pitch angle distribution of the ions summed over energy into four different energy bins.

CAPS Engineering Technical Write-up

PI: Dr. David T. Young

CAPS General Description:

The Cassini Plasma Spectrometer (CAPS) will measure the flux of ions as a function of mass per charge, and the flux of ions and electrons as a function of energy per charge and angle of arrival relative to CAPS.

CAPS Scientific Objectives:

  • To measure the composition of ionized molecules originating from Saturn's ionosphere and Titan.
  • To investigate the sources and sinks of ionospheric plasma: ion inflow/outflow, particle precipitation.
  • To study the effect of magnetospheric/ionospheric interaction on ionospheric flows.
  • To investigate auroral phenomena and Saturn Kilometric Radiation (SKR) generation.
  • To determine the configuration of Saturn's magnetic field.
  • To investigate the plasma domains and internal boundaries.
  • Investigate the interaction of the Saturn's magnetosphere with the solar wind and solar-wind driven dynamics within the magnetosphere.
  • Study the microphysics of the bow shock and magnetosheath.
  • Investigate rotationally driven dynamics, plasma input from the satellites and rings, and radial transport and angular momentum of the magnetospheric plasma.
  • Investigate magnetotail dynamics and substorm activity.
  • Study reconnection signatures in the magnetopause and tail.
  • To characterize the plasma input to the magnetosphere from the rings.
  • To characterize the role of ring/magnetosphere interaction in ring particle dynamics and erosion.
  • To study dust-plasma interactions and evaluate the role of the magnetosphere in species transport between Saturn's atmosphere and rings.
  • To investigate auroral phenomena and Saturn Kilometric Radiation (SKR) generation.
  • To study the interaction of the magnetosphere with Titan's upper atmosphere and ionosphere.
  • To evaluate particle precipitation as a source of Titan's ionosphere.
  • To characterize plasma input to magnetosphere from the icy satellites.
  • To study the effects of satellite interaction on magnetospheric particle dynamics inside and around the satellite flux tube.

CAPS Sensing Instruments:

  • Ion Mass Spectrometer
  • Ion Beam Spectrometer
  • Electron Spectrometer
  • Data Processing Unit
  • Scan Motor

CAPS Instrument Characteristics:

  • Mass (current best estimate) = 12.50 kg
  • Average Operating Power (current best estimate) = 14.50 W
  • Average Data Rate (current best estimate) = 8.00 kilobits/s

Engineering Writeup

The Cassini Plasma Spectrometer Subsystem (CAPS) will measure the flux (i.e., the flow rate or density) of ions as a function of mass per charge and the flux of ions and electrons as a function of energy per charge and angle of arrival relative to the CAPS instrument. The CAPS Subsystem consists of six major subassemblies: the in mass spectrometer, the ion beam spectrometer, the electron spectrometer, a data processing unit, a high-voltage power supply, and an actuator. For information about these components, click on their names.

The ion mass spectrometer (IMS) provides species-resolved measurements of the flux of positively charged atomic and molecular ions as a function of energy/charge vs aperture entry direction. The IMS uses a toroidal top-hat electrostatic analyzer (for energy/charge data and to create a narrow field of view) combined with a linear electric field time-of-flight mass spectrometer (for mass/charge and other species-resolving data). The IMS consists of an aperture cover/actuator, a toroidal analyzer, carbon foils, a time-of-flight spectrometer, microchannel plates, amplifier/discriminators, a time-to-digital converter, a spectrum analyzer module, and high-voltage power converters contained in high-voltage units 1 and 2. For information on these components, click on their names.

IMS Links

The IMS aperture cover protects the IMS during ground handling and during launch and early flight. The cover is a strip of flexible material that fits over the IMS annular aperture without creating a hermetic seal. To open the cover the strip is reeled into a container by a spring after the strip is released by a wax thermal actuator (WTA). Closing the cover requires ground handling to unreel the cover and re-attach its end to the cover-release mechanism. Thus, in flight, the aperture cover is a one-time use device.

The toroidal analyzer (toroidal refers to the configuration of the target reflector) consists of a baffled collimator (a device used to create a parallel beam of particles) mounted on a toroidal "top hat" electrostatic analyzer. The geometry of the collimator determines the narrow, annular (i.e., ring-shaped) IMS field of view of 12 degrees by 160 degrees, which is divided into eight angular "pixels" of 12 degrees by 20 degrees each. An electric potential between the inner and outer conductors of the electrostatic analyzer allows through this device only ions having energies within a range selected by the analyzer potential (i.e., only ions with certain energies will have trajectories, at a given analyzer potential, that navigate through the analyzer without being stopped by hitting a wall). Energy spectra are taken by stepping the analyzer potential through a set of 64 spaced values.

Eight thin carbon foils are arranged in an arc along the exit of the toroidal analyzer. The foils are the entrance to the time-of-flight spectrometer chamber formed by the linear electric field (LEF) rings. A -15 kV potential accelerates the positive ions exiting the toroidal analyzer into the foils, and this permits ions entering the IMS with as little as 1 eV of energy to pass through the foils. Molecular ions traveling through the foils are usually broken into their constituent atoms and/or molecular fragments. Molecular and atomic ions and molecular fragments exit the foils as neutrals or ions, and upon exiting the neutrals and ions eject secondary electrons into the time-of-flight chamber.

The time-of-flight spectrometer is a cylindrical chamber in the IMS, bounded by linear electric field (LEF) rings, where particles exiting the carbon foils encounter an electric field with a strength that increases linearly with distance parallel to the LEF axis of symmetry. The linear electric field is generated by a stack of thirty equally spaced aluminum rings along which a network of gigaohmn resistors establishes a quadratic electric potential with a total potential drop across the stack of rings of 30 kV.

The LEF focuses positively charged particles with energies up to approximately 15 KeV, independently of the energy and angle with which they exit the carbon foils. Microchannel plate (MCP) multipliers are located at the ends of the stack of LEF rings. Detection by the "start" (ST) MCP of rapidly travelling secondary electrons from the carbon foils is used as a time-of-flight "start" signal and for determining an ion's elevation angle with respect to the IMS aperture. Simple harmonic motion of ions in the LEF, together with knowledge of their energy gained from the toroidal analyzer setting, relates their time-of-flight, from carbon foils to the LEF MCP (at the other end of the chamber from the ST MCP), to mass per charge.

The two microchannel plates (MCPs) each consist of three circular plates of lead oxide glass with a multitude of microscopic channels running at an incline through the thickness of each plate. Electrons, ions, and neutrals striking the outer plate cause secondary electrons to cascade down the semiconductive walls of the channels. With a potential drop of about 1 kV across the thickness of a plate, there is a yield of about 300 electrons per incident particle, or a total gain of 106 electrons across the three-plate stack.

Nine anodes under the ST MCP and one anode under the LEF MCP collect the electrons emitted from the MCPs and pass the signals to two high-speed current amplifiers (one "start" amplifier for the eight 20-degree-wide anodes, and one "stop" amplifier for the LEF anode and the center ST anode). Two constant fraction discriminators accept the amplifiers' signals and send digital timing pulses (independent of the amplifiers' signal amplitude) to the time-to-digital converter (TDC). Also sent to the TDC is the identification of which of the eight annular anodes was the source of the "start" pulse and whether a "stop" pulse came from the LEF anode or the center ST anode.

The time-to-digital converter (TDC) measures the time interval between the start and stop pulses from the amplifier/discriminators. The TDC outputs an interval length to the spectrum analyzer module, along with information identifying the "start" anode and the "stop" anode. The "start" anode identity determines which of the eight 20-degree-wide IMS elevation resolution elements an ion entered through. A device in the TDC (a pulser) can inject simulated MCP signals just downstream of the MCP anodes, via high-voltage isolating capacitors, in order to test the signal handling functions of the IMS and related hardware and software in the CAPS data processing unit.

The spectrum analyzer module (SAM) provides the data gathering, sorting, and transfer functions between the TDC and the data processing unit (DPU). Time interval data from the TDC are "binned" or grouped into a pre-selected (by the DPU) set of time channels associated with certain selected ion species, whether atomic or molecular. The SAM processor performs a deconvolution of the time-of-flight spectra to obtain ion identifications, which it passes on to the DPU.

The IMS has four programmable pulse width-modulated high-voltage power converters . These converters supply high voltage to the toroidal analyzer, the LEF rings, and the LEF MCP.

The second major CAPS subassembly is the ion beam spectrometer (IBS). The IBS measures the flux of positively charged ions of all species as a function of energy/charge and aperture entry direction. The IBS consists of a hemispherical electrostatic analyzer, channel electron multipliers, amplifiers/discriminators, and high-voltage power converters. For information on these components, click on their names.

IBS Links

The hemispherical electrostatic analyzer consists of two conductive hemispheres of slightly different radius, mounted concentrically one within the other in such a way that there is a small gap between the two conductors. The electric field in the gap selects the range of energy per charge and angular direction that ions are allowed to have in order to pass through the analyzer. Energy spectra are taken by stepping the analyzer potential through a set of spaced values. Three apertures, each defining a field of view of 1.5 degrees by 150 degrees, spaced 30 degrees apart, allow particles to enter the analyzer. Particles are "focused" into three channel electron multipliers 180 degrees from each of the entrance apertures.

Ions entering the channel electron multipliers (CEMs) strike the inner semiconducting surfaces of the devices and spawn secondary electrons, which bounce down the curved channel in the CEMs, spawning more electrons with each bounce. In this way, the entry of an ion into a CEM results in a pulse of approximately 108 electrons being collected by an anode at the exit of the CEM.

The amplifiers/discriminators amplify the electron pulses collected by the CEM anodes and send the signals to the DPU's IBS interface. A device in the IBS (a pulser) can inject simulated CEM signals just downstream of the CEM anodes in order to test the signal handling functions of the IBS and related hardware and software in the DPU.

The IBS has two programmable pulse width-modulated high-voltage power converters, which supply high voltage to the hemispherical analyzer and the CEMs.

The third major CAPS subassembly is the electron spectrometer (ELS), which measures the flux of electrons as a function of energy/charge and aperture entry direction. The ELS consists of a spherical analyzer, microchannel plates, amplifiers/discriminators, a sensor management unit, and high-voltage power converters. For information on these components, click on their names.

ELS Links

The spherical analyzer consists of a baffled collimator mounted on a spherical "top hat" electrostatic analyzer. Collimator geometry determines the narrow, annular ELS field of view of 5 degrees by 160 degrees, which is divided into eight 20-degree "pixels." An electric potential between the inner and outer conductors of the electrostatic analyzer allows through this device only electrons having energies and angles within a range selected by the analyzer potential and top-hat collimation. Energy spectra are taken by stepping the analyzer potential through a set of 96 spaced values.

Two 90-degree "long" annular (i.e., curved) microchannel plates (MCPs) are arranged in a 180-degree arc along the exit of the spherical analyzer. electrons striking the surface of the MCPs are multiplied into signals collected by an arc of eight 20-degree anodes.

The anode signals are passed into eight amplifiers/discriminators via high-voltage isolating capacitors and are then accumulated by the sensor management unit. The anode identity determines which of the eight 20-degree-wide ELS elevation resolution elements an electron entered through.

The sensor management unit (SMU) controls the voltage level of the ELS high-voltage power converters in accordance with requests from the CAPS data processing unit (DPU) and passes counts of electrons (from each of the eight angular resolution elements) detected by the ELS to the DPU. A device in the SMU (a pulser) can inject simulated MCP signals just downstream of the isolating capacitors in order to test the signal handling functions of the ELS and related hardware and software in the DPU.

The ELS has two programmable pulse width-modulated high-voltage power converters that supply high voltage to the spherical analyzer and the MCPs.

The fourth major CAPS subassembly is the data processing unit (DPU). The DPU manages the acquisition and onboard data processing of all CAPS data and controls sensor and actuator motor functions. The DPU is designed to use two CPUs, in addition to the processor in the spectrum analyzer module. The first CPU accumulates IMS time-of-flight spectra and compresses all IMS data. The other CPU controls the IMS, ELS, IBS, and the actuator and performs onboard data analysis to determine what measurements will be taken and what data will be placed into housekeeping and science packets.

The DPU consists of the sensor and actuator data control interfaces, a housekeeping analog-to-digital converter, a safe/arm control, a wax thermal actuator (WTA) driver, CPUs with memory, a bus interface unit, low-voltage power converters, supplemental and replacement heaters, a radiator, and the principal structure of CAPS. For information on these components, click on their names.

DPU Links

Through its sensor and actuator data control interfaces, the DPU performs several functions. It accumulates IBS ion flux counts; it collects ELS and IMS data products from the SMU, the TDC, and the SAM; and it directly controls the IMS and IBS pulsers and high-voltage converters. The DPU feeds ion energy/charge data to, and controls, the SAM. In addition, the DPU controls the CAPS actuator (ACT) motor stepping and accepts position and status data from the ACT.

The output voltage of all nine CAPS high-voltage converters, CAPS low voltages, the actuator position encoder, and the temperature at six different locations in CAPS are monitored by a housekeeping analog-to-digital converter. In addition, two temperature sensors (one in the DPU, the other in the IMS cover release mechanism) are monitored directly by the spacecraft. These two sensors do not require that CAPS be powered.

When not enabled by the DPU (via CAPS software), all high-voltage power converters have zero potential. When high-voltage converters are enabled, a safe/arm connector on the DPU can be used during ground handling to limit high voltages to approximately 3 percent of what the DPU has commanded them to be.

The wax thermal actuators (WTAs) in the IMS cover release mechanism and the scan motor launch latch are driven and switched by a WTA driver in the DPU.

The DPU uses two nearly identical CPU boards, each containing its own RAM, ROM, and PACE 1750a microprocessor.

CAPS communicates with the Command and Data Subsystem (CDS) via a bus interface unit (BIU) that is electrically, mechanically, and thermally accommodated within the DPU.

All CAPS low-voltage power converters are housed in the DPU. Power at various voltages is supplied for use by the electronics boards in the DPU, including the BIU, and by the amplifiers, D/A converters, and other circuitry housed in the IMS, ELS, IBS, and ACT.

The CAPS supplemental heater (controlled by CAPS) and replacement heater (controlled by the spacecraft) are mounted to the inside of the DPU's top plate.

The CAPS radiator mounts to the back plate of the DPU.

Along with the actuator, the DPU box forms the principal structure of CAPS. The IMS, ELS, IBS, and the high-voltage power supplies mount to the top plate of the DPU. CAPS mounts to the spacecraft via the actuator, which is mounted to the bottom plate of the DPU.

The fifth major subassembly of the CAPS instrument is the high-voltage power supply. Two redundant power supplies, HVU1 and HVU2, mount to the top plate of the DPU.

The last subassembly of CAPS is the actuator (ACT). The ACT will rotate the CAPS instrument at a steady rate over a maximum range of 184 degrees with the acceleration/deceleration over a further 12 degrees (minimum) at either end of this range. The steady rate and acceleration/deceleration range can be adjusted in-flight, and the 216-degree total range of movement will be limited by hard stops to prevent any "wraparound" effects on the CAPS interface cables.

DATA Types: MOMT SPEC ESPC PADS

More Detailed Information

General


The CAPS Key Parameter data set consists of four different files. (1) MOMT: which contains calculated moments of the ion and electron distributions including ion density, velocity, pressure and and electron density and temperature. In addition the file includes error estimates. (2) SPEC: this file includes energy spectra data for ions (3) EPSC: electron energy spectra (4) PADS: finally, this file contains information about the pitch angle distribution of the ions summed over energy into four different energy bins.


MOMT: CAPS Calculated Moments


Definitions:

Note that CAPS moment data is at a 5 minute cadence instead of the nominal 1 minutes used by most other data types.
i = ionfh+= proton fraction<m/q> = mass per charge
e = electronv = velocityP = pressure
n = densityσ = uncertaintyT = temperature
qf = quanlity flag

Column Definitions:

Time(UTC) qfi qfe ni σ(ni) fh+ &sigma(fh+) <m/q> σ(<m/q>) vx σ(vx) vy σ(vy) vz σ(vz) |v| σ(|v|) Pi σ(Pi) ne σ(ne) Te σ(Te)

Units:

yyyy-dddThh:mm:ss.sss ion/cm3 ion/cm3 ND ND AMU AMU km/s km/s km/s km/s km/s km/s km/s km/s nPa nPa e/cm3 e/cm3 eV eV

Sample:

1997-001T00:02:30    -1    -1       0.000       0.000      0.6000      0.1500       16.00       1.000       450.0       45.00       50.00       5.000       0.000       0.000       452.8       45.28      0.5000     0.06000       0.000       0.000       35.00      0.6000
1997-001T00:07:30    -1    -1       5.000       2.241      0.5866      0.1433       14.12       1.134       443.3       44.33       43.30       4.330       25.00       2.500       446.1       44.61      0.4665     0.05933       5.000       2.241       33.66      0.5330

SPEC: CAPS Ion Energy Spectra Data


Definitions:

Columns contain ion counts (IMS singles) in the energy range (in eV/q) given below.

Column Definitions:

Time(UTC) (0.9-1.8) (1.8-3.6) (3.6-7.3) (7.3-14.6) (14.6-29.2) (29.2-58.4) (58.4-117) (117-234) (234-467) (467-934) (937-1870) (1870-3730) (3730-7480) (7500-14900) (15000-29900)

Units:

yyyy-dddThh:mm:ss.sss counts/second ...

Sample:

2004-177T00:00:30     416     477     413     403     390     389     419     452     459     447     415     457     445     425     446
2004-177T00:01:30     451     432     446     429     414     439     391     446     434     434     461     417     425     475     449

ESPC: CAPS Electron Energy Spectra Data


Definitions:

Columns contain Electron counts in the energy range (in eV/q) given below.

Column Definitions:

Time(UTC) (??-??)

Units:

yyyy-dddThh:mm:ss.sss counts/second ...

Sample:

2004-177T00:00:30     416     477     413     403     390     389     419     452     459     447     415     457     445     425     446
2004-177T00:01:30     451     432     446     429     414     439     391     446     434     434     461     417     425     475     449

PADS: CAPS Pitch Angle Distribution Data


Definitions:

CAPS PADS data depends on the orientation of the magnetic field which is taken from the MAG__SC key parameter data set. Data below indicates phase space density at a given energy over the range of indicated angles. The format is 9 angular ranges in columns at 5-50 eV followed by 9 columns indicating uncertainties, 9+9 columns at 50-500 eV, 9+9 columns at 500eV-5keV, 9+9 columns at 5-50keV. Angular range 20 degrees starting at 0 (0-20, 20-40, 40-60, 60-80, 80-100, 100-120, 120-140, 140-160, 160-180). Note that the total number of columns it 1 (time) + 72 (data+uncertainties) = 73. Units are s3/cm6.

Sample:

2004-177T00:00:30     416     477     413     403     390     389     419     452     459     416     477     413     403     390     389     419     452     459     416     477     413     403     390     389     419     452     459     416     477     413     403     390     389     419     452     459     416     477     413     403     390     389     419     452     459     416     477     413     403     390     389     419     452     459     416     477     413     403     390     389     419     452     459     416     477     413     403     390     389     419     452     459  
2004-177T00:01:30     451     432     446     429     414     439     391     446     434     451     432     446     429     414     439     391     446     434     451     432     446     429     414     439     391     446     434     451     432     446     429     414     439     391     446     434     451     432     446     429     414     439     391     446     434     451     432     446     429     414     439     391     446     434     451     432     446     429     414     439     391     446     434     451     432     446     429     414     439     391     446     434

More Detailed Information:



Table 1: CAPS Moments (MOMT) Key Parameter Data File Contents and Structure
Column Name Type Length (characters) Units Range Description
Time String 25 NA 1997-288T10:43:00Z to 2025-001T00:00:00Z Time, spacecraft event time, UTC, in ISOD format. Data are interpolated to this time from the native TDB sec. cadence of the CAPS higher level data
Ion quality flag Integer 10 NA TBD TBD indication of the quality of ion data and the method used to calculate it
Electron quality flag Integer 10 NA TBD TBD indication of the quality of electron data and the method used to calculate it
ni Float 10 ions/cm3 0 to 1e6 Ion density
s(ni) Float 10 ions/cm3 0 to 1e6 Uncertainty of ion density
fH+ Float 10 ND 0 to 1 Proton abundance
s(fH+) Float 10 ND 0 to 1 Uncertainty of proton abundance
<m/q> Float 10 AMU 2 to 100 Mean mass to charge ratio of heavier (non-proton) ions
s(<m/q>) Float 10 AMU 2 to 100 Uncertainty of mean mass to charge ratio
vx Float 10 km/s -3e5 to 3e5 Flow velocity, x component, in IAU_SATURN coordinates
s(vx) Float 10 km/s -3e5 to 3e5 Uncertainty of vx
vy Float 10 km/s -3e5 to 3e5 Flow velocity, y component, in IAU_SATURN coordinates
s(vy) Float 10 km/s -3e5 to 3e5 Uncertainty of vy
vz Float 10 km/s -3e5 to 3e5 Flow velocity, z component, in IAU_SATURN coordinates
s(vz) Float 10 km/s -3e5 to 3e5 Uncertainty of vz
|v| Float 10 km/s 0 to 3e5 Flow speed
s(|v|) Float 10 km/s 0 to 3e5 Uncertainty of flow speed
Pi Float 10 nPa 0 to 1 Ion pressure (define)
s(Pi) Float 10 nPa 0 to 1 Uncertainty of ion pressure
ne Float 10 e/cm3 0 to 1e6 Electron density
s(ne) Float 10 e/cm3 0 to 1e6 Uncertainty of electron density
Te Float 10 eV 0 to 1e6 Electron temperature (define)
s(Te) Float 10 eV 0 to 1e6 Uncertainty of electron temperature

This file contains 245 characters per line (plus \n), and 288 lines per file (24 hours at 5 minute cadence.) This is 69 kbytes per file, or 98 Mbytes over four years.



Table 2: CAPS Ion Spectra (SPEC) Key Parameter Data File Contents and Structure
Column Name Type Length (characters) Units Range Description
Time String 25 NA 1997-288T10:43:00Z to 2025-001T00:00:00Z Time, spacecraft event time, UTC, in ISOD format. Data are from the one CAPS A cycle (32 seconds) which falls entirely within this time ±30s
Data, Energy 59-62 Integer 8 Counts per second [0,5e6] Ion Counts (IMS singles), summed over 1 A cycle and Energy steps 59 to 62, or 0.9 to 1.8 eV/q
Data, Energy 55-58 Integer 8 Counts per second [0,5e6] Ion Counts (IMS singles), summed over 1 A cycle and Energy steps 55 to 58, or 1.8 to 3.6 eV/q
Data, Energy 51-54 Integer 8 Counts per second [0,5e6] Ion Counts (IMS singles), summed over 1 A cycle and Energy steps 51 to 54, or 3.6 to 7.3 eV/q
Data, Energy 47-50 Integer 8 Counts per second [0,5e6] Ion Counts (IMS singles), summed over 1 A cycle and Energy steps 47 to 50, or 7.3 to 14.6 eV/q
Data, Energy 43-46 Integer 8 Counts per second [0,5e6] Ion Counts (IMS singles), summed over 1 A cycle and Energy steps 43 to 46, or 14.6 to 29.2 eV/q
Data, Energy 39-42 Integer 8 Counts per second [0,5e6] Ion Counts (IMS singles), summed over 1 A cycle and Energy steps 39 to 42, or 29.3 to 58.4 eV/q
Data, Energy 35-38 Integer 8 Counts per second [0,5e6] Ion Counts (IMS singles), summed over 1 A cycle and Energy steps 35 to 38, or 58.4 to 117 eV/q
Data, Energy 31-34 Integer 8 Counts per second [0,5e6] Ion Counts (IMS singles), summed over 1 A cycle and Energy steps 31 to 34, or 117 to 234 eV/q
Data, Energy 27-30 Integer 8 Counts per second [0,5e6] Ion Counts (IMS singles), summed over 1 A cycle and Energy steps 27 to 30, or 234 to 467 eV/q
Data, Energy 23-26 Integer 8 Counts per second [0,5e6] Ion Counts (IMS singles), summed over 1 A cycle and Energy steps 23 to 26, or 467 to 934 eV/q
Data, Energy 19-22 Integer 8 Counts per second [0,5e6] Ion Counts (IMS singles), summed over 1 A cycle and Energy steps 19 to 22, or 937 to 1870 eV/q
Data, Energy 15-18 Integer 8 Counts per second [0,5e6] Ion Counts (IMS singles), summed over 1 A cycle and Energy steps 15 to 18, or 1870 to 3730 eV/q
Data, Energy 11-14 Integer 8 Counts per second [0,5e6] Ion Counts (IMS singles), summed over 1 A cycle and Energy steps 11 to 14, or 3750 to 7480 eV/q
Data, Energy 7-10 Integer 8 Counts per second [0,5e6] Ion Counts (IMS singles), summed over 1 A cycle and Energy steps 7 to 10, or 7500 to 14900 eV/q<
Data, Energy 1-6 Integer 8 Counts per second [0,5e6] Ion Counts (IMS singles), summed over 1 A cycle and Energy steps 3 to 6, or 15000 to 29900 eV/q

This file contains 145 characters per line (plus \n), and 1440 lines per file (24 hours at 1 minute cadence.) This is 205 kbytes per file, or 291 Mbytes over four years.



Table 3: CAPS Electron pitch angle distribution (PADS) Key Parameter Data File Contents and Structure
Column Name Type Length (characters) Units Range Description
Time String 25 NA 1997-288T10:43:00Z to 2025-001T00:00:00Z Time, spacecraft event time, UTC, in ISOD format. Data are from the one CAPS A cycle (32 seconds) which falls entirely within this time ±30s
Energy Range Integer 2 NA [0,3] 0= 5eV to 50 eV, 1=50eV to 500 eV, 2=500 eV to 5 keV, 3=5 keV to 50 keV
PSD, 0-20° Float 10 s3/cm6   Phase space density, average of all pixels centered on 0-20° pitch angle
PSD, 20-40° Float 10 s3/cm6   Phase space density, average of all pixels centered on 20-40° pitch angle
PSD, 40-60° Float 10 s3/cm6   Phase space density, average of all pixels centered on 40-60° pitch angle
PSD, 60-80° Float 10 s3/cm6   Phase space density, average of all pixels centered on 60-80° pitch angle
PSD, 80-100° Float 10 s3/cm6   Phase space density, average of all pixels centered on 80-100° pitch angle
PSD, 100-120° Float 10 s3/cm6   Phase space density, average of all pixels centered on 100-120° pitch angle
PSD, 120-140° Float 10 s3/cm6   Phase space density, average of all pixels centered on 120-140° pitch angle
PSD, 140-160° Float 10 s3/cm6   Phase space density, average of all pixels centered on 140-160° pitch angle
PSD, 160-180° Float 10 s3/cm6   Phase space density, average of all pixels centered on 160-180° pitch angle
(PSD), 0-20° Float 10 s3/cm6   Uncertainty of phase space density
(PSD), 20-40° Float 10 s3/cm6   Uncertainty of phase space density
(PSD), 40-60° Float 10 s3/cm6   Uncertainty of phase space density
(PSD), 60-80° Float 10 s3/cm6   Uncertainty of phase space density
(PSD), 80-100° Float 10 s3/cm6   Uncertainty of phase space density
(PSD), 100-120° Float 10 s3/cm6   Uncertainty of phase space density
(PSD), 120-140° Float 10 s3/cm6   Uncertainty of phase space density
(PSD), 140-160° Float 10 s3/cm6   Uncertainty of phase space density
(PSD), 160-180° Float 10 s3/cm6   Uncertainty of phase space density

This file contains 207 characters per line (plus \n), 4 lines per minute (each of four energy ranges) and 5760 lines per file (24 hours at 1 minute cadence.) This is 1.198 Mbytes per file or 1.75 Gbytes over four years.

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CAPS_ESPC

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CAPS_IMNT

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CAPS_ISPC

2004 001 - 009   
2004 016 - 016   
2004 020 - 021   
2004 051 - 051   
2004 073 - 074   
2004 092 - 099   
2004 101 - 152   
2004 157 - 169   
2004 175 - 185   
2004 194 - 351   
2004 353 - 366   
2005 001 - 006   
2005 015 - 146   
2005 171 - 172   
2005 187 - 365   
2006 001 - 365   
2007 001 - 093   
2007 095 - 254   
2007 258 - 279   
2007 288 - 288   
2007 291 - 365   
2008 001 - 087   
2008 093 - 093   
2008 099 - 366   
2009 001 - 071   
2009 077 - 123   
2009 125 - 365   
2010 001 - 306   
2010 317 - 337   
2010 339 - 365   
2011 001 - 166   
2012 078 - 154   

Cassini CDA home: http://www.mpi-hd.mpg.de/dustgroup/cassini/


The Cosmic Dust Analyzer (CDA) registers the impacts of micron and nano-sized dust grains in interplanetary space. It can study the physical and chemical properties of the particles hitting the sensitive area. The CDA consists of two subinstruments: The main sensor is Dust Analyzer (DA) designed to analyse the particles in accord to their speed, mass, charge, chemistry, and pitch angle. The second is the High-Rate Detector (HRD) below the DA only counting the number of impacts with a frequency up to 10,000 counts per second. The latter turns out advanageous when flying through high-density areas when the DA runs into saturation. The purpose is to quantify the density of dust in space and in the environment of Saturn.

This CDA data is based on so-called "impact counters" that register the number of impacts within a standard time interval of 64 seconds. All events are evaluated by the onboard software due to the characteristics of their electric signal (risetime, amplitude and integral). Depending on its features, each event increases the value of one out of 27 counters or "impact classes". This classification is priority sequenced and re-arranged to the six most common groups of impacts: rates of noise, wall, cat, iit, iitbig, and qi-flares. The rates are corrected for systematic errors. The dust density in the volume of space is also calculated.



CDA Engineering Technical Write-up
PI: Dr. Ralf Srama


CDA General Description:
........................
The Cosmic Dust Analyzer (CDA) measures the ice and dust particles
in the Saturnian system.
The device can also identify the electric charge, speed, direction,
and mass of individual particles.
It can also determine their chemical composition when the chemical
target is hit.


figure: cda-schematic.jpg


Signal processing:
..................
The entrance of the DA is of a 4-fold electric conductive grid.
The two innermost grids are connected to a charge amplifier;
a current (QP, ``charge primary'') will be induced,
when a charged particle passes through.
The tilting of these two grids cause an asymmetry in the
rising and declining flanks of the QP-signal that permits
a precise determination of the inflow angle relative
to the boresight
(the boresight is the symmetry axis of the bowl).
The rise time of the QP signal will be proportional to the
particle velocity v,
and the amplitude proportional to the charge q.
The transmission of the four grids ranges between 80% and
95%, depending on the incoming angle of the dust particle.

IIT impacts:
When a dust particle hits the sensitive area of the
Impact Ionisation Target (IIT), it will be destroyed,
eventually forming a plasma could.
The positive ions are attracted by a small electric grid
in front of the multiplier (MP) in the centre of the
device.
The electrons fall back and produce a negative
electric flux.

CAT impacts:
The Chemical Analyser Target (CAT) is a segment (radius:
8 cm) of the IIT and operates in combination
with the multiplier as a time-of-flight mass
spectrometer.
An incoming dust particle is smashed into its atoms due
to the high voltage of +1000 V.
The positively charged nuclei are accelerated to the
electric grid in front of the multiplier (MP) and
arrive sequentially in accord to their mass:
hydrogen needs about 550 ns for the distance from the
CAT to the electric grid, and rhodium about 5000 ns.
These time-dependent arrivals of the nuclei act
like a spectrometer for the atomic masses.
The data set provides only the total number of all
impact features that hit the CAT.



CDA Scientific Objectives:
..........................
  • Extended studies of interplanetary dust to the orbit of Saturn.
  • Determine the composition of dust particles in interplanetary space, in the environment of Jupiter and Saturn, and the Saturnian moons.
  • Investigate the dust streams in the Jovian and Saturnian system.
  • Determine the flux of interstellar particles during the solar activity cycle.
  • Map the size distribution of the particles.
  • Analyse the material of the Saturnian rings, and beyond the E ring.
  • Determine the particle orbits for the identification of their possible sources.
  • Study dynamical processes (erosional and electromagnetic) responsible for the E ring structure.
  • Determine dust and meteoroid distribution both in the vicinity of the rings and in interplanetary space.
  • Analyse the composition of the subsurface ejecta on Enceladus.
  • Investigate interactions with the ring system and determine the role of satellites as a source for ring particles.
  • Instrument Characteristics: ........................... Total mass: 17.2 kg Diameter IIT: 0.41 m Diameter CAT: 0.16 m Sensitive area: 0.0825 m^2 (IIT) + 0.0073 m^2 (CAT) Aperture: +/- 45¡ Measurement of charges: 10^{-15} -- 10^{-12} C Instrument dead time: ~1 sec Operating power: 11.7 W Data rate: 524 bps
    General
    ----------------------------
    The CDA Key Parameter files contain impact rates of dust
    for six classified counter groups, while
    each group is a combination of more specific counters.
    See chapters 3 and 4.3 of the manual for further details.
    
    Guide to the Impact Counters of the CDA (v1.2)
    
    
    Definitions:
    ----------------------------
    JulDay = Julian Date
    dT = time interval since last readout of data, minimum 64 seconds
    dN = total number of impacts
    r_noise = rate of noise impacts (dead time corrected)
    r_wall = rate of wall impacts (dead time corrected)
    r_cat = rate of impacts on the Chemical Analyzer Target (dead time corrected)
    r_iit = rate of impacts on the Impact Ionization Target (dead time corrected)
    r_iitbig = rate of strong impacts on the IIT (dead time corrected)
    r_qi = rate of QI-flares (dead time corrected)
    r_all = rate of all impacts (dead time corrected)
    A_eff = effective area sensitive to pitch angle of the Kepler-RAM
    v_dust = velocity of the spacecraft
    n = number density of dust particles
    
    
    Column Definitions:
    ----------------------------
    (Time/UTC) (JulDay) (dT) (dN) (r_noise) (r_wall) (r_cat) (r_iit) (r_iitbig) (r_qi) (r_all) (A_eff) (v_dust) (n)
    
    Units:
    ----------------------------
    yyyy-dddThh:mm:ss JulDay sec # sec-1 sec-1 sec-1 sec-1 sec-1 sec-1 sec-1 m^2 m/sec m-3
    
    Sample:
    ----------------------------
    2006-251T05:03:55  2453986.7110567   64   41   0.000000   0.025162   0.000000   0.000000   0.000000   1.006481   1.031643   0.07187760  6194.7936  2.3169E-03
    2006-251T05:04:59  2453986.7117975   64   40   0.000000   0.023674   0.000000   0.000000   0.000000   0.923295   0.946970   0.06967440  6197.1740  2.1932E-03
    2006-251T05:06:03  2453986.7125382   64   39   0.000000   0.000000   0.000000   0.000000   0.000000   0.195036   0.195036   0.06967440  6197.1740  4.5170E-04
    2006-251T05:07:07  2453986.7132789   64   45   0.000000   0.032402   0.000000   0.000000   0.000000   1.425691   1.458093   0.06967440  6199.5570  3.3756E-03
    
    
    
    
    Data Availability: (less detail)
    CDA_2005

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    2005 279 - 365   
    CDA_2006

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    2006 299 - 339   
    2006 365 - 365   
    CDA_2007

    2007 001 - 193   
    2007 199 - 224   
    2007 229 - 254   
    2007 258 - 365   
    CDA_2008

    2008 001 - 099   
    2008 109 - 212   
    2008 219 - 299   
    CDA_2009

    2009 100 - 285   
    2009 287 - 365   
    CDA_2010

    2010 001 - 036   
    2010 041 - 109   
    CDA_CNTS

    2005 180 - 277   
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    2006 365 - 365   
    2007 001 - 193   
    2007 199 - 224   
    2007 229 - 254   
    2007 258 - 365   
    2008 001 - 099   
    2008 109 - 212   
    2008 219 - 299   
    2009 100 - 285   
    2009 287 - 365   
    2010 001 - 036   
    2010 041 - 109   

    Cassini MAG home: http://www.sp.ph.ic.ac.uk/cassini/

    The MAG instrument comprises a fluxgate magnetometer (FGM) and a vector helium magnetometer capable of operating in both vector and scalar mode (V/SHM). The instrument is intended to measure small changes in fields spanning four orders of magnitude with extremely high sensitivity. This goal is achieved in part by mounting the sensors on an 11-metre spacecraft boom; the V/SHM at the end of the boom, the FGM halfway along. The magnetometer boom distances the sensors from the magnetic field associated with the spacecraft and its subsystems, and especially from spacecraft-generated temporal field variations. Spacing the sensors at different distances along the boom allows the spacecraft fields to be better characterised and removed from the observations.

    Both magnetometers are capable of measuring the magnetic-field vector at rates from 0 Hz up to 10 Hz (VHM) or at least 30 Hz (FGM). The VHM optimises low- frequency vector measurements in weak fields. The FGM is best suited to high- frequency measurements and can operate over an extremely wide dynamic range, from very weak fields up to strong fields. The twin-sensor configuration contributes to overall instrument reliability; if one sensor fails, field measurements can be made with the other sensor, with sufficient performance to achieve many of the major objectives of the investigation.

    The magnetometer Key Parameter data set includes calibrated vector magnetic field measurements averaged over one minute intervals. Magnetic field vectors are provided in several different coordinate systems (KSM, KSO, KG, SC and RTN). RTN coordinates are provided during the cruise phase of the mission (before DOY 160, 2004) while coordinates that are more useful for study in the magnetosphere (KSM,KSO,KG) are are provided only after DOY 145, 2004. Data in spacecraft (SC) coordinates are provided throughout the mission.

    PDS_VERSION_ID                     = PDS3                                     
    MISSION_NAME                       = "CASSINI"                                
    SPACECRAFT_NAME                    = "CASSINI"                                
    RECORD_TYPE                        = STREAM                                   
    LABEL_REVISION_NOTE                = "NULL"                                   
                                                                                  
    OBJECT                             = INSTRUMENT                               
      INSTRUMENT_HOST_ID               = "CO"                                     
      INSTRUMENT_ID                    = "MAG"                                    
                                                                                  
    OBJECT                             = INSTRUMENT_INFORMATION                   
        INSTRUMENT_NAME                = "DUAL TECHNIQUE MAGNETOMETER"            
        INSTRUMENT_TYPE                = "MAGNETOMETER"                           
        INSTRUMENT_DESC                = "                                        
                                                                                  
      INSTRUMENT DESCRIPTION                                                      
      ======================                                                      
        The MAG instrument comprises a fluxgate magnetometer (FGM) and a          
        vector helium magnetometer capable of operating in both vector and        
        scalar mode (V/SHM). The instrument is intended to measure small          
        changes in fields spanning four orders of magnitude with extremely        
        high sensitivity. This goal is achieved in part by mounting the           
        sensors on an 11-metre spacecraft boom; the V/SHM at the end of the       
        boom, the FGM halfway along. The magnetometer boom distances the          
        sensors from the magnetic field associated with the spacecraft and        
        its subsystems, and especially from spacecraft-generated temporal         
        field variations. Spacing the sensors at different distances along        
        the boom allows the spacecraft fields to be better characterised and      
        removed from the observations. However, mounting the sensors on a         
        boom could result in their orientation with respect to the                
        spacecraft axes changing from time to time, for example after             
        spacecraft manoeuvres. A means of sensor-alignment determination has      
        been provided by the Cassini project - the Science CAlibration            
        Subsystem, SCAS. This system consists of two, perpendicular, coils        
        rigidly mounted on the spacecraft body with a known alignment to the      
        spacecraft axes. These coils produce well-defined magnetic fields on      
        command which can be detected by the sensors and used to correct for      
        any changes in sensor orientation.                                        
                                                                                  
        Both magnetometers are capable of measuring the magnetic-field            
        vector at rates from 0 Hz up to 10 Hz (VHM) or at least 30 Hz (FGM).      
        The VHM optimises low- frequency vector measurements in weak fields.      
        The FGM is best suited to high- frequency measurements and can            
        operate over an extremely wide dynamic range, from very weak fields       
        up to Earth's strong field.                                               
                                                                                  
        The twin-sensor configuration contributes to overall instrument           
        reliability; if one sensor fails, field measurements can be made          
        with the other sensor, with sufficient performance to achieve many        
        of the major objectives of the investigation. Reliability has been        
        further increased by the provision of redundant instrument power          
        supplies and data processing units, and by careful selection of           
        electronic components that can survive the radiation environments         
        encountered during the long cruise phase of the mission and in the        
        Saturnian system. The VHM provides the stability needed to maintain       
        calibrations, obtained in the solar wind, whilst Cassini is inside        
        the Saturnian magnetosphere for long periods during the four-year         
        tour.                                                                     
                                                                                  
        An implicit feature of scalar or resonance magnetometers are null         
        zones which arise if the ambient field falls outside a cone of 45         
        degrees half angle with respect to the optical axis of the                
        magnetometer. These null zones result in the signal being                 
        dramatically weakened, causing the absolute accuracy of the               
        instrument to suffer. When Cassini is inside 4 RS a requirement has       
        been placed on the mission to avoid spacecraft orientations which         
        cause the planetary field to lie within the null zones of the SHM.        
                                                                                  
        Other features of the instrument that have been driven by the             
        characteristics of the mission and by the design of the spacecraft        
        are to be found in the data processing unit (DPU). The DPU contains       
        a bus interface unit (BIU), provided by the Cassini project for           
        interfacing to the onboard data handling subsystem (CDS) bus. In          
        line with the spacecraft design, the DPU is capable of handling           
        Packet Telemetry and Telecommands, and features a flexible telemetry      
        storage and generation scheme to support the multiple telemetry           
        modes of the spacecraft. The Tour operations concept requires that        
        the DPU is able to handle trigger commands which initiate multiple        
        actions within the instrument (macro commanding). Further, in order       
        to optimise the analysis of discrete events such as shock crossings,      
        a snapshot capability has been implemented by which up to 16 Mbytes       
        of data can be stored for later downlink at higher time resolution        
        than normal. This capability can be initiated by command or               
        triggered by pre-defined events.                                          
                                                                                  
        Magnetic-field information is also needed by other investigations on      
        the spacecraft. To this end magnetic-field data are made available        
        to onboard users every second. These onboard ancillary data are raw       
        and uncalibrated vectors, the data source being selectable by             
        command between the two sensors.                                          
                                                                                  
        In total, the instrument consists of the two boom-mounted sensors,        
        subchassis #1 (an assembly containing electronics for the FGM, VHM        
        and SHM, the heater- control electronics, the power supplies and          
        power-management system) and subchassis #2 (an assembly containing        
        the data processing unit). Both subchassis are mounted in bay 4 of        
        the Orbiter upper equipment module (UEM). The instrument                  
        ground-support equipment was provided by KFKI and TUB.                    
                                                                                  
        Table I lists the main characteristics of the instrument. Power and       
        data-rate values vary according to instrument mode. The values given      
        in the table are for the delivered flight model where power values        
        include power drawn by the Cassini-provided BIU.                          
                                                                                  
          TABLE  I                                                                
          Main Instrument Characteristics                                         
                                                                                  
          MASS                                                                    
          V/SHM Sensor                                       0.71 kg              
          FGM Sensor                                         0.44 kg              
          Subchassis#1 (Power Supplies, Sensor Electronics)  5.15 kg              
          Subchassis#2 (DPU)                                 2.52 kg              
          Total                                              8.82 kg              
                                                                                  
          POWER                                                                   
          Sleep Mode                                         7.50 W               
          Vector/Vector Mode (FGM+VHM)                      11.31 W               
          Vector/Scalar Mode (FGM+SHM)                      12.63 W               
                                                                                  
          NORMAL DOWNLINK DATA RATE                                               
          FGM                                 32 Vectors per second               
          VHM                                  2 Vectors per second               
          SHM                                    1 Value per second               
          Housekeeping                           24 bits per second               
          Total                                2000 bits per second               
                                                                                  
          DYNAMIC RANGE, RESOLUTION                                               
          FGM                                        +/-40nT, 4.9pT               
                                                   +/-400nT, 48.8pT               
                                                 +/-10,000nT, 1.2nT               
                                                 +/-44,000nT, 5.4nT               
          VHM                                                                     
                                                     +/-32nT, 3.9pT               
                                                   +/-256nT, 31.2pT               
          SHM                                                                     
                                              256nT - 16384nT,36 pT               
                                                                                  
                                                                                  
        THE FGM                                                                   
        -------                                                                   
          The FGM sensor is mounted halfway along the magnetometer boom; its      
          associated analog electronics form part of the electronics              
          assembly on Subchassis#1. A cable of approximately 6.5-meter            
          length runs along the boom between sensor and electronics. A high       
          efficiency, tuned drive design of the electronics has been chosen       
          to reduce power consumption and the effect of cable loading.            
                                                                                  
          The FGM is similar to the Imperial College instrument flown on          
          Ulysses, and to many others flown on numerous missions. It is           
          based on three single-axis ring-core fluxgate sensors mounted           
          orthogonally on a machinable glass ceramic block. Ceramic is            
          chosen for its low thermal expansion coefficient, minimising            
          misalignments between sensors due to temperature changes. In each       
          sensor, a drive coil is wound around a high-permeability ring-core      
          which is completely enclosed in a sense winding. The drive coil is      
          driven by a crystal-controlled 15.625 kHz square wave which is          
          used to generate a magnetic field that drives the core into             
          saturation twice per cycle. The three drive coils are connected in      
          series to simplify the cabling and circuitry. The presence of an        
          ambient magnetic-field component parallel to the axis of the sense      
          coil causes the saturation of the core to become asymmetrical.          
          This asymmetry induces a second harmonic of the drive frequency in      
          the sense coil which is proportional to the magnitude of the            
          magnetic-field component along that axis. The signal is processed       
          through a narrow band amplifier tuned to the second harmonic of         
          the drive frequency, which attenuates harmonics other than the          
          second. The result is integrated, converted to a current and fed        
          back to the sensor coil to null the ambient field. The integrated       
          output voltage, amplified and corrected for scale factor and            
          alignment errors, is proportional to the ambient field. The three       
          analogue vector components are passed to the DPU for analogue to        
          digital conversion and data processing. The noise performance of        
          the FGM, measured on the ground at the analogue output of the           
          electronics, is better than 5 pT/Hz at 1 Hz. The electronics can        
          be checked in flight using an in-flight calibration (IFC)               
          capability built into the electronics and controlled by command         
          from the DPU. The IFC applies a fixed offset to each of the three       
          vector outputs corresponding to a signal of approximately 10 nT.        
          The frequency, number of on/off cycles, of the IFC is selectable        
          by command.                                                             
                                                                                  
          Changing the electronics feedback path and the output                   
          amplification allows the sensor to be operated in one of four           
          different full scale magnetic field ranges, as listed in Table I.       
          The largest range (+/-44,000 nT) was included mainly for ground         
          testing in the Earth's field. Switching between ranges in normal        
          operations is automatic, controlled by the DPU. If the magnitude        
          of any of the FGM magnetic-field components exceeds an upper            
          threshold for more than a specified number of samples, the DPU          
          will switch the FGM to a higher range. Similarly, if all three          
          component value magnitudes fall below a lower threshold for more        
          than a specified number of samples, the DPU will switch the FGM to      
          a lower range. All parameters are modifiable by command and             
          autoranging can also be disabled and manual range changes               
          commanded.                                                              
                                                                                  
          A 1W heater has been provided to maintain the FGM within its            
          operating temperature range of -30 to +50 degrees C. The specially      
          designed, non-magnetic unit is mounted on the ceramic sensor block      
          and has control electronics on Subchassis#1. Further thermal            
          control is provided by an aluminised mylar-covered fibreglass case      
          over the sensor block and by three, project-provided, radioactive       
          heater units mounted at equal distances around the base of the          
          sensor (these units provide a total of 3W).                             
                                                                                  
                                                                                  
        THE V/SHM                                                                 
        ---------                                                                 
          The V/SHM sensor is the flight-spare Ulysses vector-helium              
          magnetometer sensor with an added small pair of coils nested            
          inside the larger Helmholtz coils used in the vector mode. The          
          sensor is mounted at the end of the 11- meter magnetometer boom. A      
          set of cables running the length of the boom connects it to the         
          VHM and SHM electronics on Subchassis#1. The VHM electronics box        
          is also the Ulysses flight-spare unit with small modifications to       
          change the sensor operating ranges and to compensate for the            
          different boom cable lengths. A new electronics board has been          
          added to Subchassis#1 containing the electronics to operate in the      
          scalar mode.                                                            
                                                                                  
          The operation of the magnetometer is based on field-dependent           
          light absorption (the Zeeman effect) and optical pumping to sense       
          the magnetic field. Helium in an absorption cell is excited by a        
          radio-frequency (RF) discharge to maintain a population of              
          metastable long-lived atoms. Infrared radiation (wavelength 1083        
          nm) from a helium lamp, also generated by RF excitation, passes         
          through a circular polariser and the absorption cell to an              
          infrared detector. The absorption (pumping efficiency) of the           
          helium in the cell is dependent on the ambient magnetic-field           
          direction. The optical pumping efficiency is proportional to            
          cos^2(Theta) where Theta is the angle between the optical axis and      
          the direction of the magnetic field. This directional dependence        
          is utilised in the vector mode by applying low- frequency sweep         
          fields rotating about the cell which allow the extraction of the        
          three orthogonal ambient-field components. These fields are fed         
          back using a set of triaxial Helmholtz coils mounted on the sensor      
          housing around the cell. In the scalar mode, the directional            
          dependence results in a 'field of view' restricted to a cone with       
          half angle approximately 45 degrees, centred on the optical axis        
          detector.                                                               
                                                                                  
          Changing the VHM sweep fields allows the sensor to operate in           
          different ranges. Two VHM ranges have been selected for Cassini         
          (see Table I). As for the FGM, automatic ranging has been               
          implemented in the DPU. The VHM electronics also have an internal       
          autoranging capability (used for the Ulysses instrument). A single      
          range has been implemented for the SHM. Injection of known              
          currents into the Helmholtz-coil system provide an in- light            
          calibration (IFC) capability. The calibration fields apply an           
          offset of approximately 1/8 of the full scale range to each vector      
          component. A non-magnetic proportional heater using up to 2W is         
          incorporated into the V/SHM sensor and is controlled from               
          electronics built into the VHM electronics box on Subchassis#1.         
          The operating temperature range of the sensor is -10 to +40             
          degrees C.                                                              
                                                                                  
          In the scalar mode, a weak AC field at the Larmor frequency, which      
          opposes the optical pumping, is applied to the cell. This field         
          causes a reduction in the transmitted light  detected by the IR         
          detector. The Larmor frequency, which is proportional to the            
          ambient magnetic field, is measured. In order to track the ambient      
          field the applied field is frequency modulated so that the              
          detector output contains a signal component harmonically related        
          to the modulation frequency. The proportionality constant is the        
          gyromagnetic ratio which for helium is 28.023561 Hz/nT. Detection       
          and measurement of the Larmor frequency leads to a very accurate        
          measurement of the ambient field magnitude. The result is passed        
          as a 20-bit scalar word from the SHM electronics to the DPU. A          
          more detailed description of the V/SHM may be found in Kellock et       
          al. (1996).  Smith et al. (2001) provides a detailed description        
          of the SHM operation and observations from the Earth Swingby in         
          August 1999.                                                            
                                                                                  
                                                                                  
      INSTRUMENT ELECTRONICS                                                      
      ======================                                                      
        The instrument electronics are all mounted in the Upper Equipment         
        Module in bay 4 and are split between two subchassis assemblies.          
        Subchassis#1 contains the sensor electronics, the power supplies and      
        power management system, as well as the heater control and                
        instrument housekeeping electronics; its mass is given in Table I.        
        On the underside of the subchassis are the power- management board,       
        the FGM electronics board and the SHM electronics board. The              
        power-management board contains a total of 14 non-latching power          
        switches and cross-strapping circuitry for the two redundant              
        secondary power supplies. The top side of the subchassis contains         
        the VHM electronics box, two small boards to the left of the VHM box      
        with latching relays to switch between VHM and SHM operation, two         
        redundant secondary power supplies (PSU1 and PSU2), a dedicated BIU       
        power supply (PSU0), and the FGM heater-control electronics and           
        housekeeping circuitry. Proportional control electronics for the VHM      
        heater are located within the VHM box. The power supplies and             
        switches are Imperial College designs used on previous missions and       
        feature built-in overcurrent trips.                                       
                                                                                  
        The basic power distribution scheme is described in Kellock et al.        
        (1996). Power switches for the secondary voltage lines are                
        controlled by the active processing unit and power switches for the       
        power supplies and processing units themselves are controlled by          
        discrete commanding from the spacecraft via the BIU and the Common        
        Core (CC).                                                                
                                                                                  
        Subchassis#2 contains the DPU, consisting of two redundant processor      
        systems plus a small CC and the BIU. When power is first supplied         
        from the spacecraft, only the BIU and the CC become active, powered       
        from PSU0. The BIU allows data transfer to and from the spacecraft,       
        the CC processes commands and data for power up of the secondary          
        power supplies (PSU1 or PSU2) and the processors (PUA or PUB). Each       
        processor system is based on an 80C86 processor with 4-MHz clock,         
        32-kByte PROM, 128-kByte Hi-Rel RAM and 16-MByte state-of-the-art         
        commercial DRAM. The systems normally operate singly but can be           
        operated in parallel. A high-accuracy 16-bit analogue to digital          
        converter (ADC) is integrated into each processor system for sensor       
        data collection. Two ADC clock speeds are available, 1 MHz and 2          
        MHz, the former being the default speed. Tantalum shielding has been      
        used for the ADCs, DRAMs and Operational Amplifiers to reduce their       
        susceptibility to radiation.  The DPU boards are folded around the        
        subchassis. The electronic components face the subchassis, because        
        the 2.4 mm thick 16-layer boards provide additional radiation             
        shielding. The Sensor Interface Board is on the right hand side.          
        The flexible connection board goes through subchassis cutouts to the      
        Processor Board on the other side. The JPL-provided BIU, plus its         
        associated cabling, is located on the left side.                          
                                                                                  
        To satisfy the demands of a deep-space mission with limited               
        communications, the DPU has been designed with a large measure of         
        autonomy and sophisticated data-handling functions. These functions       
        include the following: telecommand handling, sensor autoranging and       
        IFC, sensor data collection, sensor data processing, snapshot data        
        handling, telemetry generation, error correction, fault detection         
        and recovery, and onboard ancillary data generation. Some of the          
        functions of the DPU are described below.                                 
                                                                                  
        The DPU is designed to handle both the packet telecommand standard        
        adopted by Cassini, used for normal commanding, and discrete              
        telecommands used when the processor is not active. A variety of          
        command functions are supported and are discussed later. The DPU          
        must be able to accept telecommands at all times, in all operational      
        modes. Commands may be for immediate execution, or can contain            
        relative or absolute timetags for delayed execution (relative             
        timetags cause execution at a fixed time with respect to reception        
        of the command, absolute timetags cause execution at specific             
        spacecraft times). As noted earlier, a macro commanding capability        
        has been implemented whereby sequences of instrument commands can be      
        stored in the DPU and the sequence started by executing a macro           
        command.                                                                  
                                                                                  
        Hamming single-bit error correction and double-bit error detection        
        is provided for all memory devices except those in the BIU. Single        
        Event Upsets (SEUs) can change the content of memory cells, cyclic        
        access to every memory cell corrects single-bit and reduces the risk      
        of double-bit errors. Memory scrubb- ing is initiated every 64            
        seconds in the Hi-Rel RAM and the 16-MByte, multi- snapshot, DRAM.        
        It takes about 1 hour to scrub the complete RAM. Additional memory        
        checks can be initiated by command: occurences of single and double-      
        bit errors are monitored. The PROMS are checked separately and            
        contain a pre- defined error pattern for detection. If a permanent        
        RAM problem arises, the DPU can be commanded to run its software          
        directly from PROM. In-flight tests have also been implemented for        
        the ADC to check the noise and conversion and settling times on each      
        analogue channel.                                                         
                                                                                  
        Both processor systems contain four separate dual-level latch-up          
        detectors, one for the processor, one for the multi-snapshot memory,      
        and one each for the ADC +/-12V supply voltages. Detectors of             
        similar design have been flown on the GEOTAIL, WIND and SOHO              
        spacecraft. If a latch up is detected in the processor, it will be        
        immediately switched off and on again and the instrument will be          
        automatically reconfigured into its previous mode. Latch ups in           
        either the memory or the ADC will cause it to be immediately              
        switched off and back on again. There is also a hardware watchdog         
        function in the DPU which will detect problems in the DPU program         
        flow and which initiates a hardware reset followed by an automatic        
        instrument reconfiguration."                                              
                                                                                  
                                                                                  
    END_OBJECT                         = INSTRUMENT_INFORMATION                   
                                                                                  
    OBJECT                             = INSTRUMENT_REFERENCE_INFO                
      REFERENCE_KEY_ID                 = "KELLOCKETAL1996"                        
    END_OBJECT                         = INSTRUMENT_REFERENCE_INFO                
                                                                                  
    OBJECT                             = INSTRUMENT_REFERENCE_INFO                
      REFERENCE_KEY_ID                 = "SMITHETAL2001"                          
    END_OBJECT                         = INSTRUMENT_REFERENCE_INFO                
                                                                                  
    END_OBJECT                         = INSTRUMENT                               
    END                                                                           
    

    General


    The magnetometer Key Parameter data set includes calibrated vector magnetic field measurements averaged over one minute intervals. Magnetic field vectors are provided in several different coordinate systems (KSM, KSO, KG, SC and RTN). RTN coordinates are provided during the cruise phase of the mission (before DOY 160, 2004) while coordinates that are more useful for study in the magnetosphere (KSM,KSO,KG) are are provided only after DOY 145, 2004. Data in spacecraft (SC) coordinates are provided throughout the mission.


    KSM: Magnetic Field in KSM Coordinates


    Column Definitions:

    Time(UTC) Bx By Bz |B|

    Units:

    yyyy-dddThh:mm:ss.sss nT nT nT nT

    Sample:

    2004-182T00:00:58.000      0.897      5.648     -2.254      6.147
    2004-182T00:01:58.000      0.954      5.669     -2.222      6.163
    

    KSO: Magnetic Field in KSO Coordinates


    Column Definitions:

    Time(UTC) Bx By Bz |B|

    Units:

    yyyy-dddThh:mm:ss.sss nT nT nT nT

    Sample:

    2004-182T00:00:58.000      0.897      5.648     -2.254      6.147
    2004-182T00:01:58.000      0.954      5.669     -2.222      6.163
    

    KG: Magnetic Field in KG Coordinates


    Column Definitions:

    Time(UTC) Bx By Bz |B|

    Units:

    yyyy-dddThh:mm:ss.sss nT nT nT nT

    Sample:

    2004-182T00:00:58.000      0.897      5.648     -2.254      6.147
    2004-182T00:01:58.000      0.954      5.669     -2.222      6.163
    

    SC: Magnetic Field in SC Coordinates


    Column Definitions:

    Time(UTC) Bx By Bz |B|

    Units:

    yyyy-dddThh:mm:ss.sss nT nT nT nT

    Sample:

    2004-182T00:00:58.000      0.897      5.648     -2.254      6.147
    2004-182T00:01:58.000      0.954      5.669     -2.222      6.163
    

    RTN: Magnetic Field in RTN Coordinates


    Column Definitions:

    Time(UTC) Br Bt Bn |B|

    Units:

    yyyy-dddThh:mm:ss.sss nT nT nT nT

    Sample:

    2004-182T00:00:58.000      0.897      5.648     -2.254      6.147
    2004-182T00:01:58.000      0.954      5.669     -2.222      6.163
    

    More Detailed Information:


    Data Availability: (less detail)
    MAG_KG

    2004 060 - 060   
    2004 064 - 190   
    2004 192 - 366   
    2005 001 - 006   
    2005 015 - 365   
    2006 001 - 328   
    2006 332 - 365   
    2007 001 - 093   
    2007 095 - 254   
    2007 258 - 279   
    2007 291 - 365   
    2008 001 - 011   
    2008 024 - 158   
    2008 163 - 366   
    2009 001 - 071   
    2009 077 - 123   
    2009 125 - 261   
    2009 264 - 365   
    2010 001 - 079   
    2010 082 - 306   
    2010 314 - 319   
    2010 321 - 322   
    2010 324 - 337   
    2010 339 - 365   
    2011 001 - 040   
    2011 042 - 068   
    2011 070 - 357   
    2011 359 - 365   
    2012 001 - 267   
    2012 269 - 293   
    2012 303 - 359   
    2012 362 - 366   
    2013 001 - 146   
    2013 148 - 365   
    2014 001 - 127   
    2014 129 - 134   
    2014 136 - 365   
    2015 001 - 365   
    2016 001 - 001   
    2016 003 - 066   
    2016 068 - 234   
    2016 236 - 250   
    2016 254 - 357   
    2017 001 - 258   
    MAG_KSM

    2003 195 - 336   
    2003 338 - 338   
    2003 340 - 341   
    2003 343 - 365   
    2004 001 - 060   
    2004 064 - 190   
    2004 192 - 366   
    2005 001 - 006   
    2005 015 - 365   
    2006 001 - 328   
    2006 332 - 365   
    2007 001 - 093   
    2007 095 - 254   
    2007 258 - 279   
    2007 291 - 365   
    2008 001 - 011   
    2008 024 - 158   
    2008 163 - 366   
    2009 001 - 071   
    2009 077 - 123   
    2009 125 - 261   
    2009 264 - 365   
    2010 001 - 079   
    2010 082 - 306   
    2010 314 - 319   
    2010 321 - 322   
    2010 324 - 337   
    2010 339 - 365   
    2011 001 - 040   
    2011 042 - 068   
    2011 070 - 357   
    2011 359 - 365   
    2012 001 - 267   
    2012 269 - 293   
    2012 303 - 359   
    2012 362 - 366   
    2013 001 - 146   
    2013 148 - 365   
    2014 001 - 127   
    2014 129 - 134   
    2014 136 - 365   
    2015 001 - 365   
    2016 001 - 001   
    2016 003 - 066   
    2016 068 - 234   
    2016 236 - 250   
    2016 254 - 357   
    2017 001 - 258   
    MAG_KSO

    2003 195 - 336   
    2003 338 - 338   
    2003 340 - 341   
    2003 343 - 365   
    2004 001 - 060   
    2004 064 - 190   
    2004 192 - 366   
    2005 001 - 006   
    2005 015 - 365   
    2006 001 - 328   
    2006 332 - 365   
    2007 001 - 093   
    2007 095 - 254   
    2007 258 - 279   
    2007 291 - 365   
    2008 001 - 011   
    2008 024 - 158   
    2008 163 - 366   
    2009 001 - 071   
    2009 077 - 123   
    2009 125 - 261   
    2009 264 - 365   
    2010 001 - 079   
    2010 082 - 306   
    2010 314 - 319   
    2010 321 - 322   
    2010 324 - 337   
    2010 339 - 365   
    2011 001 - 040   
    2011 042 - 068   
    2011 070 - 357   
    2011 359 - 365   
    2012 001 - 267   
    2012 269 - 293   
    2012 303 - 359   
    2012 362 - 366   
    2013 001 - 146   
    2013 148 - 365   
    2014 001 - 127   
    2014 129 - 134   
    2014 136 - 365   
    2015 001 - 365   
    2016 001 - 001   
    2016 003 - 066   
    2016 068 - 234   
    2016 236 - 250   
    2016 254 - 357   
    2017 001 - 258   
    MAG_RTN

    2003 355 - 360   
    2004 001 - 060   
    2004 064 - 159   
    MAG_SC

    1999 228 - 235   
    1999 237 - 244   
    1999 248 - 257   
    1999 259 - 262   
    1999 296 - 296   
    2000 020 - 020   
    2000 037 - 039   
    2000 046 - 059   
    2000 113 - 113   
    2000 127 - 127   
    2000 129 - 132   
    2000 135 - 137   
    2000 141 - 201   
    2000 248 - 251   
    2000 253 - 314   
    2000 321 - 366   
    2001 001 - 027   
    2001 341 - 341   
    2002 334 - 334   
    2003 001 - 039   
    2003 106 - 132   
    2003 136 - 142   
    2003 144 - 179   
    2003 195 - 336   
    2003 338 - 338   
    2003 340 - 341   
    2003 343 - 365   
    2004 001 - 060   
    2004 064 - 190   
    2004 192 - 366   
    2005 001 - 006   
    2005 015 - 365   
    2006 001 - 328   
    2006 332 - 365   
    2007 001 - 093   
    2007 095 - 254   
    2007 258 - 279   
    2007 291 - 365   
    2008 001 - 011   
    2008 024 - 158   
    2008 163 - 366   
    2009 001 - 071   
    2009 077 - 123   
    2009 125 - 261   
    2009 264 - 365   
    2010 001 - 079   
    2010 082 - 306   
    2010 314 - 319   
    2010 321 - 322   
    2010 324 - 337   
    2010 339 - 365   
    2011 001 - 040   
    2011 042 - 068   
    2011 070 - 357   
    2011 359 - 365   
    2012 001 - 267   
    2012 269 - 293   
    2012 303 - 359   
    2012 362 - 366   
    2013 001 - 146   
    2013 148 - 365   
    2014 001 - 127   
    2014 129 - 134   
    2014 136 - 365   
    2015 001 - 365   
    2016 001 - 001   
    2016 003 - 066   
    2016 068 - 234   
    2016 236 - 250   
    2016 254 - 357   
    2017 001 - 258   

    Cassini MIMI home: http://sd-www.jhuapl.edu/CASSINI/

    The Magnetospheric Imaging Instrument (MIMI) will be used study the energetic charged particle enviroment of Saturn's space envirnment, or magnetosphere, using novel techniques . Charged particles are measured with energies between 7 keV/nucleon to > 152 MeV/ nucleon. It will obtain the first remote global images of Saturn's hot plasmas using the new technique of "Energetic Neutral Atom Imaging". It will also perform comprehensive in situ hot plasma measurements, including charge state, elemental compostion, and angular distrubutions. The new "Energetic Neutral Atom Imaging" technique utilized by MIMI will also allow the MIMI team to make sensitive measurments of the neutral exospheric densities of Titan, and possibly also of the icy satellites.

    The MIMI Instumentation consists of a Main Electronics Unit MEU and the three sensor heads: The Low Energy Magnetosheric Measurment System, or LEMMS, the The Charge Energy Mass Spectrometer, or CHEMS, and The Ion and Neutral Camera , or INCA. The Low Energy Magnetospheric Measurment System (LEMMS) mesures high energy ion and electron energy and angular distributions from 20 keV to ~130 MeV. To obtain angular distributions it is mounted on a rotating platform which permits motor driven rotations of the sensor head by 360 deg. about the spacecraft -Y axis The CHarge Energy Mass Spectrometer (CHEMS), provided by the University of Maryland, measures the charge state, compostion, and energy of ions with energies between about 10 to 220 keV/charge. The Ion and Neutral Camera (INCA) images of the global distribution of energetic ions for energies from 7 keV/nucleon to 8 MeV/nucleon, discriminated according to energy and mass species (Oxygen and Hydrogen). To obtain these images INCA measures the arrival directions, energy, and mass species of Energetic Neutral Atoms (ENA's) using the new technique of ENA imaging.

    The MIMI Key Parameter file contains minute averaged particle flux counts in the various detectors of the different sub-systems. The data files include: LEMMS channels A0-8, C0-7, P1-5, E0-4 and the calculated anisotropy for C5 and A5; CHEMS ion counts for H+, He+, He++, and O+ in four averaged energy bands; and INCA time-of-flight (TOF) counts in 7 channels averaged over the field of view for either ions or neutrals depending on the operating mode.





    MIMI Engineering Technical Write-up
    PI: Dr. Stamatios M. Krimigis

    MIMI General Description:

    The Magnetospheric Imaging Instrument (MIMI) is designed to: (1) measure the composition, charge state and energy distribution of energetic ions and electrons; (2) detect fast neutral species; and, (3) conduct remote imaging of the Saturn's magnetosphere. This information will be used to study the overall configuration and dynamics of the magnetosphere and its interactions with the solar wind, Saturn's atmosphere, Titan, rings, and icy satellites.

    MIMI Scientific Objectives:

    • To determine the global configuration and dynamics of hot plasma in the magnetosphere of Saturn.
    • To monitor and model magnetospheric substorm-like activity and correlate this activity with Saturn Kilometric Radiation (SKR) observations.
    • To study magnetosphere/ionosphere coupling through remote sensing of aurora and measurements of energetic ions and electrons.
    • To investigate plasma energization and circulation processes in the magnetotail of Saturn.
    • To determine through imaging and composition studies the magnetosphere/satellite interactions at Saturn and understand the formation of clouds of neutral hydrogen, nitrogen, and water products.
    • To measure electron losses due to interactions with whistler waves.
    • To study the global structure and temporal variability of Titan's atmosphere.
    • Monitor the loss rate and composition of particles lost from Titan's atmosphere due to ionization and pickup.
    • To study Titan's interaction with the magnetosphere of Saturn and and the solar wind.
    • To determine the importance of Titan's exosphere as a source for the atomic hydrogen torus in Saturn's outer magnetosphere.
    • To investigate the absorption of energetic ions an electrons by Saturn's rings and icy satellites.
    • To analyze Dione's exosphere.

    MIMI Instrument Characteristics:

    • Mass (current best estimate) = 16.00 kg
    • Average Operating Power (current best estimate) = 14.00 W
    • Average Data Rate (current best estimate) = 7.00 kilobits/s

    The Magnetospheric Imaging Instrument (MIMI) will provide global images of Saturnian hot plasmas remotely and will perform comprehensive direct measurements of hot plasma, including charge state and elemental composition.

    The MIMI instrument consists of one set of electronics, the MIMI electronics box, servicing three detector heads that perform the various measurements: the low-energy magnetospheric measurements system (LEMMS), the charge-energy-mass spectrometer (CHEMS), and the ion and neutral camera (INCA). For information on these components, click on their names.

    (MIMI Links)

    The MIMI electronics box contains the data processing unit (DPU) and the digital processing electronics for all three detector heads.

    The low-energy magnetospheric measurements system (LEMMS) detector head will measure low- and high-energy proton, ion, and electron angular distributions. The LEMMS head is mounted on a scan platform capable of 180-degree rotations. The platform is mounted so that the rotation axis is oriented perpendicular to the spacecraft X axis and so that its extrapolation intersects the spacecraft Z axis.

    The charge-energy-mass spectrometer (CHEMS) head will measure the charge state and composition of ions in the most energetically important portion of the Saturnian magnetospheric plasma.

    The ion and neutral camera (INCA) will make two different types of measurements. It will obtain with very high sensitivity the three-dimensional distribution, velocities, and rough composition of magnetospheric and interplanetary ions for those regions in which the energetic ion fluxes are very low. The INCA instrument will also obtain remote images of the global distribution of the energetic neutral emission of hot plasmas in the Saturnian magnetosphere, measuring the composition and velocities of those energetic neutrals for each image pixel.

    General


    The MIMI Key Parameter file contains minute averaged particle flux counts in the various detectors of the different sub-systems. The data files include: LEMMS channels A0-8, C0-7, P1-5, E0-4 and the calculated anisotropy for C5 and A5; CHEMS ion counts for H+, He+, He++, and O+ in four averaged energy bands; and INCA time-of-flight (TOF) counts in 7 channels averaged over the field of view for either ions or neutrals depending on the operating mode.


    KEY: MIMI Key Parameters


    Definitions:

    LEMMS_A =
    LEMMS_C =
    LEMMS_P =
    LEMMS_E =
    LEMMS_??_anisotropy = (LEMMS_??_ANI) =
    LEMMS_scanning =
    CHEMS_?_DPPS =
    INCA_H_TOF =
    INCA_Mode =

    All data columns have units of ...


    Column Definitions:

    Time(UTC) LEMMS_A0 A1 A2 A3 A4 A5 A6 A7 A8 LEMMS_C0 C1 C2 C3 C4 C5 C6 C7 LEMMS_P1 P2 P3 P4 P5 LEMMS_E0 E1 E2 E3 E4 LEMMS_C5_ANI A5_ANI LEMMS_SCANNING CHEMS_H+_DPPS0-7 8-15 16-23 24-13 CHEMS_He+_DPPS0-7 8-15 16-23 24-13 CHEMS_He++_DPPS0-7 8-15 16-23 24-13 CHEMS_O+_DPPS0-7 8-15 16-23 24-13 INCA_H_TOF_0 1 2 3 4 5 6 7 INCA_MODE

    Units:

    yyyy-dddThh:mm:ss.sss (...)*27columns (...)*2columns String (...)*16columns (...)*8columns String

    Sample:

    2004-182T00:00:00.000   58.74243        18.32098        2.70684         1.17325         0.25212         0.15926         0.02995         0.01682         0.00000         0.89825         7.74853         4.00916         1.87409         1.51137         1.40637         0.43600         0.05642         0.00167         0.00033         0.00000         0.00022         0.00000         0.19612         0.00798         0.00104         0.00002         0.00248         1.00000         1.00000         yes             0.00000         0.87712         0.00000         0.00000         0.00000         0.00000         0.15207         0.00000         0.00000         0.00000         0.00000         0.00000         0.00000         0.00000         0.00000         0.00000         0.22325         0.05121         0.17927         0.51493         1.14478         3.48130         10.12023        44.16069        ion             
    2004-182T00:01:00.000   40.80641        11.33794        2.69422         1.64417         0.28458         0.15926         0.02995         0.01253         0.00000         0.76702         6.86737         4.02369         1.79755         1.34805         1.27421         0.46803         0.06447         0.00222         0.00011         0.00000         0.00011         0.00000         0.22527         0.00737         0.00110         0.00002         0.00313         1.00000         1.00000         yes             0.87711         0.45623         0.87711         0.00000         0.00000         0.00000         0.00000         0.00000         0.00000         0.00000         0.00000         0.00000         0.00000         0.00000         0.00000         0.00000         0.18224         0.03474         0.12497         0.36588         0.85914         2.64863         7.93489         32.03806        ion 
    

    More Detailed Information:


    Data Availability: (less detail)
    MIMI_KEY

    1999 001 - 365   
    2000 001 - 366   
    2001 001 - 365   
    2002 001 - 365   
    2003 001 - 365   
    2004 001 - 366   
    2005 001 - 365   
    2006 001 - 365   
    2007 001 - 218   

    Cassini RPWS home: http://www-pw.physics.uiowa.edu/plasma-wave/cassini/home.html

    The Cassini Radio and Plasma Wave Science instrument consists of three electric field sensors, three search coil magnetometers, and a Langmuir probe as well as an array of receivers covering the frequency range from 1 Hz to 16 MHz with varying degrees of spectral and temporal resolution.

    The Cassini Radio and Plasma Wave Science (RPWS) calibrated summary key parameter data set includes reduced temporal and spectral resolution spectral information calibrated in units of spectral density for the entire Cassini mission. This data set includes calibrated values binned and averaged within 1 minute by 0.1 decade spectral channels. Data for this data set are acquired by the RPWS Low Frequency Receiver (LFR), Medium Frequency Receiver (MFR), and High Frequency Receiver (HFR). This data set is intended to provide numerical summary data which can be used in conjunction with other Cassini fields and particles key parameter data sets to establish trends, select events, or simply as a browse data set for the Cassini RPWS archive. This data set should be among the first used by a user of any of the RPWS archive as it will lead one to information required to search for more detailed or highly specialized products.

    PDS_VERSION_ID          = PDS3
    LABEL_REVISION_NOTE     = "W. Kurth, June 2003;"
    RECORD_TYPE             = STREAM
    
    OBJECT                  = INSTRUMENT
      INSTRUMENT_HOST_ID      = CO
      INSTRUMENT_ID           = RPWS
    
      OBJECT                  = INSTRUMENT_INFORMATION
        INSTRUMENT_NAME         = "RADIO AND PLASMA WAVE SCIENCE"
        INSTRUMENT_TYPE         = "PLASMA WAVE SPECTROMETER"
        INSTRUMENT_DESC         = "
    
    
      Abstract
      ========
        The Cassini Radio and Plasma Wave Science instrument consists of
        three electric field sensors, three search coil magnetometers, and a
        Langmuir probe as well as an array of receivers covering the
        frequency range from 1 Hz to 16 MHz with varying degrees of spectral
        and temporal resolution.
    
        The text of this instrument description has been abstracted from the
        instrument paper [GURNETTETAL2003]:
    
        Gurnett, D. A., W. S. Kurth, D. L. Kirchner, G. B. Hospodarsky, T.
        F. Averkamp, P. Zarka, A. Lecacheux, R. Manning, A. Roux, P. Canu,
        N. Cornilleau-Wehrlin, P. Galopeau, A. Meyer, R. Bostrom, G.
        Gustafsson, J.-E. Wahlund, L. Aahlen, H. O. Rucker, H. P. Ladreiter,
        W. Macher, L. J. C. Woolliscroft, H. Alleyne, M. L. Kaiser, M. D.
        Desch, W. M.  Farrell, C. C. Harvey, P. Louarn, P. J. Kellogg, K.
        Goetz, and A.  Pedersen, The Cassini Radio and Plasma Wave Science
        Investigation, Space Sci. Rev., in press, 2002.
    
    
      Scientific Objectives
      =====================
        The primary objectives of the Cassini Radio and Plasma Wave
        investigation are to study radio emissions, plasma waves, thermal
        plasma, and dust in the vicinity of Saturn.
    
        Objectives concerning radio emissions include:
    
          Improve our knowledge of the rotational modulation of Saturn's
          radio sources, and hence of Saturn's rotation rate.
    
          Determine the location of the SKR source as a function of
          frequency, and investigate the mechanisms involved in generating
          the radiation.
    
          Obtain a quantitative evaluation of the anomalies in Saturn's
          magnetic field by performing direction-finding measurements of the
          SKR source.
    
          Establish if gaseous ejections from the moons Rhea, Dione, and
          Tethys are responsible for the low frequency narrow-band radio
          emissions.
    
          Determine if SKR is controlled by Dione's orbital position.
    
          Establish the nature of the solar wind-magnetosphere interaction
          by using SKR as a remote indicator of magnetospheric processes.
    
          Investigate the relationship between SKR and the occurrence of
          spokes and other time dependent phenomena in the rings.
    
          Study the fine structure in the SKR spectrum, and compare with the
          fine structure of terrestrial and Jovian radio emissions in order
          to understand the origin of this fine structure.
    
        Objectives concerning plasma waves include:
    
          Establish the spectrum and types of plasma waves associated with
          gaseous emissions from Titan, the rings, and the icy satellites.
    
          Determine the role of plasma waves in the interaction of Saturn's
          magnetospheric plasma (and the solar wind) with the ionosphere of
          Titan.
    
          Establish the spectrum and types of plasma waves that exist in the
          radiation belt of Saturn.
    
          Determine the wave-particle interactions responsible for the loss
          of radiation belt particles.
    
          Establish the spectrum and types of waves that exist in the
          magnetotail and polar regions of Saturn's magnetosphere.
    
          Determine if waves driven by field-aligned currents along the
          auroral field lines play a significant role in the auroral charged
          particle acceleration.
    
          Determine the electron density in the magnetosphere of Saturn,
          near the icy moons, and in the ionosphere of Titan.
    
        Objectives concerning lightning include:
    
          Establish the long-term morphology and temporal variability of
          lightning in the atmosphere of Saturn.
    
          Determine the spatial and temporal variation of the electron
          density in Saturn's ionosphere from the low frequency cutoff and
          absorption of lightning signals.
    
          Carry out a definitive search for lightning in Titan's atmosphere
          during the numerous close flybys of Titan.
    
          Perform high-resolution studies of the waveform and spectrum of
          lightning in the atmosphere of Saturn, and compare with
          terrestrial lightning.
    
        Objectives concerning thermal plasma include:
    
          Determine the spatial and temporal distribution of the electron
          density and temperature in Titan's ionosphere.
    
          Characterize the escape of thermal plasma from Titan's ionosphere
          in the downstream wake region.
    
          Constrain and, when possible, measure the electron density and
          temperature in other regions of Saturn's magnetosphere.
    
        Objectives concerning dust include:
    
          Determine the spatial distribution of micron-sized dust particles
          through out the Saturnian system.
    
          Measure the mass distribution of the impacting particles from
          pulse heightanalyses of the impact waveforms.
    
          Determine the possible role of charged dust particles as a source
          of field-aligned currents.
    
    
      Calibration
      ===========
        An extensive series of amplitude calibrations, frequency responses,
        phase calibrations, and instrument performance checks were carried
        out on the RPWS prior to launch, both before and after integration
        on the spacecraft. These tests and calibrations were performed at
        room temperature (25øC), -20øC, and 40øC. While there are
        calibration signals available in the instrument for in-flight
        calibration purposes, these are mainly used to check for drifts due
        to aging or radiation exposure. The primary calibration information
        to derive physical units (spectral density, etc.) is derived from
        the prelaunch tests.
    
    
      Operational Considerations
      ==========================
        The different types of receivers used to cover the spectral and
        temporal range covered by the RPWS does not lend itself to a
        monolithic, synchronous mode of operation. Nevertheless, to reduce
        the magnitude of the in-flight operations to an acceptable level
        requires that many of the measurements be scheduled in a systematic
        way. The approach is to attempt to acquire survey information in the
        form of uniform spectral and temporal observations at a low enough
        data rate, ~1 kbps, to ensure that such coverage is available for
        the entire Saturnian tour and for a large portion of the cruise and
        approach to Saturn. The survey data set will support spatial
        mapping, statistical studies, and studies of dynamical effects in
        the magnetosphere and their possible correlation with solar wind
        variations. In addition to the survey information, special
        observations will be added (sometimes at greatly increased data
        rates) at specific locations or times to provide enhanced
        information required by several of the science objectives. The
        special observations may include full polarization and
        direction-finding capability or high spectral or temporal resolution
        observations by the high frequency receiver, wideband measurements
        at one of the possible bandwidths, acquisition of delta-ne/ne
        measurements, or intensive wave-normal analysis afforded by
        acquiring five-channel waveforms on an accelerated schedule. While
        minimizing the number of different modes in which the instrument is
        operated both simplifies operations and yields a more manageable
        data set, flexibility (for example in the duty cycle of wideband
        measurements) increases the likelihood that enhanced measurements
        can be integrated successfully with the resource requirements of the
        other instruments. One of the resources which will be most limited
        on Cassini is the overall data volume; RPWS requires large data
        volumes for some of its measurements.
    
    
      Detectors
      =========
        The RPWS utilizes three 10-m electric antennas, three magnetic
        antennas, and a Langmuir probe for detectors.  Three monopole
        electric field antennas, labeled Eu, Ev, and Ew, are used to provide
        electric field signals to the various receivers. The physical
        orientations of these three antennas relative to the x, y, and z
        axes of the spacecraft are given below. However, the electrical
        orientations of these are strongly affected by the asymmetric nature
        of the ground plane of the spacecraft chassis.  These electrical
        orientations are incorporated into the calibrations, primarily of
        the High Frequency Reciever.  By electronically taking the
        difference between the voltages on the Eu and Ev monopoles, these
        two antennas can be used as a dipole, Ex, aligned along the x axis
        of the spacecraft.
    
        Physical orientations of the electric monopole antennas:
         Antenna 	theta (degrees)	phi (degrees)
            Eu        107.5           24.8
            Ev        107.5          155.2
            Ew         37.0           90.0
    
        The angle theta is the polar angle measured from the spacecraft +z
        axis.  The angle phi is the azimuthal angle, measured from the
        spacecraf +x axis.
    
        The tri-axial search coil magnetic antennas, labeled Bx, By, and Bz,
        are used to detect three orthogonal magnetic components of
        electromagnetic waves. The search coil axes are aligned along the x,
        y, and z axes of the spacecraft.
    
        The spherical Langmuir probe is used for electron density and
        temperature measurements.  This is extended from the spacecraft in
        approximately the -x direction, in spacecraft coordinates.
    
    
      Electronics
      ===========
        The electronics consists of five receivers. These receivers are
        connected to the antennas described above by a network of switches.
        The high frequency receiver (HFR) provides simultaneous auto- and
        cross-correlation measurements from two selected antennas over a
        frequency range from 3.5 kHz and 16 MHz. By switching the two inputs
        of this receiver between the three monopole electric antennas, this
        receiver can provide direction-of-arrival measurements, plus a full
        determination of the four Stokes parameters. The high frequency
        receiver includes a processor that performs all of its digital
        signal processing, including data compression. The high frequency
        receiver also includes a sounder transmitter that can be used to
        transmit short square wave pulses from 3.6 to 115.2 kHz. When used
        in conjunction with the high frequency receiver, the sounder can
        stimulate resonances in the plasma, most notably at the electron
        plasma frequency, thereby providing a direct measurement of the
        electron number density.  The medium frequency receiver (MFR)
        provides intensity measurements from a single selected antenna over
        a frequency range from 24 Hz to 12 kHz. This receiver is usually
        operated in a mode that toggles every 32 seconds between the Ex
        electric dipole antenna and the Bx magnetic search coil, thereby
        providing spectral information for both the electric and magnetic
        components of plasma waves. The low frequency receiver (LFR)
        provides intensity measurements from 1 Hz to 26 Hz, typically from
        the Ex electric dipole antenna and the Bx magnetic antenna. The
        five-channel waveform receiver (WFR) collects simultaneous waveforms
        from up to five sensors for short intervals in one of two frequency
        bands, either 1 to 26 Hz, or 3 Hz to 2.5 kHz. When connected to two
        electric and three magnetic antennas, this receiver provides wave
        normal measurements of electromagnetic plasma waves. The wideband
        receiver is designed to provide nearly continuous wideband waveform
        measurements over a bandwidth of either 60 Hz to 10.5 kHz, or 800 Hz
        to 75 kHz. These waveforms can be analyzed on the ground in either
        the temporal domain, or in the frequency domain (Fourier
        transformed) to provide high-resolution frequency-time spectrograms.
        In a special frequency-conversion mode of operation, the high
        frequency receiver can provide waveforms to the wideband receiver in
        a 25-kHz bandwidth that is tuneable to any frequency between 125 kHz
        and 16 MHz.
    
        The Langmuir probe controller is used to sweep the bias voltage of
        the probe over a range from -32 to +32 V in order to obtain the
        current-voltage characteristics of the probe, and thereby the
        electron density and temperature. The controller can also set the
        bias voltage on the Eu and Ev monopoles over a range from -10 to +10
        V in order to operate them in a current collection mode for
        delta-ne/ne measurements.
    
        The RPWS data processing unit consists of three processors. The
        first processor, called the low-rate processor, controls all
        instrument functions, collects data from the high frequency
        receiver, the medium frequency receiver, the low frequency receiver,
        and the Langmuir probe, and carries out all communications with the
        spacecraft Command and Data System (CDS). The second processor,
        called the highrate processor, handles data from the wideband and
        five-channel waveform receivers and passes the data along to the
        low-rate processor for transmission to the CDS. The third processor,
        called the data compression processor, is primarily used for data
        compression, but can also perform specialized operations such as
        on-board dust detection by using waveforms from the wideband
        receiver."
    
      END_OBJECT              = INSTRUMENT_INFORMATION
    
      OBJECT                  = INSTRUMENT_REFERENCE_INFO
        REFERENCE_KEY_ID        = "GURNETTETAL2003"
      END_OBJECT              = INSTRUMENT_REFERENCE_INFO
    
    END_OBJECT              = INSTRUMENT
    
    END
    

    General


    The Cassini Radio and Plasma Wave Science (RPWS) calibrated summary key parameter data set includes reduced temporal and spectral resolution spectral information calibrated in units of spectral density for the entire Cassini mission. This data set includes calibrated values binned and averaged within 1 minute by 0.1 decade spectral channels. Data for this data set are acquired by the RPWS Low Frequency Receiver (LFR), Medium Frequency Receiver (MFR), and High Frequency Receiver (HFR). This data set is intended to provide numerical summary data which can be used in conjunction with other Cassini fields and particles key parameter data sets to establish trends, select events, or simply as a browse data set for the Cassini RPWS archive. This data set should be among the first used by a user of any of the RPWS archive as it will lead one to information required to search for more detailed or highly specialized products.


    KEY: RPWS Electric and Magnetic Spectral Densities


    Definitions:

    The first column following the time is a quality flag (0=good, 9=bad). The remaining columns contain spectral densities for 73 electric frequency ranges and 42 magnetic frequency ranges. The frequencies are given as the first line in the file (tagged at time 0). Units are: electric (V**2/M**2/HZ), magnetic (nT**2/HZ).

    Sample:

    1998-364T00:00:00.000 0 1.000e+00 1.259e+00 1.585e+00 1.995e+00 2.512e+00 3.162e+00 3.981e+00 5.012e+00 6.310e+00 7.943e+00 1.000e+01 1.259e+01 1.585e+01 1.995e+01 2.512e+01 3.162e+01 3.981e+01 5.012e+01 6.310e+01 7.943e+01 1.000e+02 1.259e+02 1.585e+02 1.995e+02 2.512e+02 3.162e+02 3.981e+02 5.012e+02 6.310e+02 7.943e+02 1.000e+03 1.259e+03 1.585e+03 1.995e+03 2.512e+03 3.162e+03 3.981e+03 5.012e+03 6.310e+03 7.943e+03 1.000e+04 1.259e+04 1.585e+04 1.995e+04 2.512e+04 3.162e+04 3.981e+04 5.012e+04 6.310e+04 7.943e+04 1.000e+05 1.259e+05 1.585e+05 1.995e+05 2.512e+05 3.162e+05 3.981e+05 5.012e+05 6.310e+05 7.943e+05 1.000e+06 1.259e+06 1.585e+06 1.995e+06 2.512e+06 3.162e+06 3.981e+06 5.012e+06 6.310e+06 7.943e+06 1.000e+07 1.259e+07 1.585e+07 1.000e+00 1.259e+00 1.585e+00 1.995e+00 2.512e+00 3.162e+00 3.981e+00 5.012e+00 6.310e+00 7.943e+00 1.000e+01 1.259e+01 1.585e+01 1.995e+01 2.512e+01 3.162e+01 3.981e+01 5.012e+01 6.310e+01 7.943e+01 1.000e+02 1.259e+02 1.585e+02 1.995e+02 2.512e+02 3.162e+02 3.981e+02 5.012e+02 6.310e+02 7.943e+02 1.000e+03 1.259e+03 1.585e+03 1.995e+03 2.512e+03 3.162e+03 3.981e+03 5.012e+03 6.310e+03 7.943e+03 1.000e+04 1.259e+04
    1998-364T09:29:30.000 0 1.289e-10 4.974e-10 6.656e-11 5.014e-11 3.239e-11 7.604e-11 3.407e-11 1.991e-11 3.144e-11 1.334e-11 1.193e-11 1.137e-11 1.252e-11 3.991e-12 7.630e-12 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 2.561e-15 1.710e-15 1.447e-15 8.533e-16 6.752e-16 5.361e-16 4.415e-16 3.811e-16 2.814e-16 2.243e-16 1.375e-16 9.883e-17 7.919e-17 7.469e-17 5.498e-17 2.769e-17 1.904e-17 2.791e-17 1.492e-17 4.438e-17 3.695e-17 3.278e-17 3.338e-17 3.839e-17 4.947e-17 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 0.000e+00 1.614e-02 1.681e-03 8.961e-06 8.776e-05 1.460e-05 8.238e-06 6.509e-06 2.456e-06 2.626e-06 4.472e-06 6.485e-07 3.800e-07 1.867e-06 3.414e-07 5.901e-07 2.485e-07 1.171e-07 5.882e-08 4.623e-08 4.499e-08 7.515e-08 0.000e+00 0.000e+00 3.387e-09 3.054e-09 1.979e-09 2.528e-09 1.535e-09 2.167e-09 6.983e-10 0.000e+00 0.000e+00 1.772e-09 1.895e-09 1.094e-09 1.422e-09 1.001e-09 1.458e-09 2.011e-09 2.776e-09 3.483e-09 6.085e-09
    1998-364T09:30:30.000 0 1.487e-10 2.024e-10 2.072e-10 1.618e-10 3.382e-11 4.090e-11 1.943e-11 3.065e-11 1.508e-11 1.444e-11 8.073e-12 9.119e-12 5.161e-12 3.744e-12 2.915e-12 1.416e-12 8.641e-13 8.899e-13 7.453e-13 2.950e-13 4.877e-13 4.549e-13 3.418e-13 3.468e-13 1.690e-13 1.280e-13 1.024e-13 7.251e-14 8.583e-14 2.393e-14 1.988e-14 1.482e-14 1.163e-14 1.245e-14 6.842e-15 6.230e-15 2.812e-15 1.913e-15 1.231e-15 9.328e-16 6.966e-16 5.090e-16 4.476e-16 3.655e-16 2.642e-16 1.967e-16 1.380e-16 1.006e-16 7.925e-17 6.612e-17 5.643e-17 2.763e-17 1.906e-17 2.682e-17 1.406e-17 4.151e-17 3.695e-17 3.392e-17 3.338e-17 3.789e-17 5.421e-17 4.591e-17 3.263e-17 3.515e-17 3.343e-17 3.532e-17 3.352e-17 3.163e-17 3.186e-17 3.605e-17 3.720e-17 4.568e-17 6.305e-17 2.522e-03 7.767e-04 5.252e-05 3.082e-05 2.962e-05 9.035e-06 4.844e-06 1.583e-06 2.443e-06 5.390e-06 5.220e-07 3.524e-07 2.088e-06 3.468e-07 5.481e-07 2.738e-07 1.509e-07 1.042e-07 3.284e-08 3.221e-08 4.472e-08 1.131e-08 2.559e-08 4.076e-09 2.721e-09 1.310e-09 1.580e-09 1.475e-09 1.250e-09 8.723e-10 9.935e-10 7.127e-10 1.163e-09 1.843e-09 1.135e-09 1.390e-09 1.232e-09 1.545e-09 1.661e-09 2.193e-09 2.856e-09 3.279e-09
    

    More Detailed Information:


    DSKEY.CAT

    PDS_VERSION_ID          = PDS3
    LABEL_REVISION_NOTE     = "
      2003-01-12, William Kurth (U. IOWA), initial;
      2003-06-26, William Kurth (U. IOWA), general revision;"
    RECORD_TYPE             = STREAM
    
    OBJECT                  = DATA_SET
      DATA_SET_ID             = "CO-V/E/J/S/SS-RPWS-4-SUMM-KEY60S-V1.0"
    
      OBJECT                  = DATA_SET_INFORMATION
        DATA_SET_NAME           = "
          CASSINI V/E/J/S/SS RPWS SUMMARY KEY PARAMETER 60S V1.0"
        DATA_SET_COLLECTION_MEMBER_FLG = "N"
        DATA_OBJECT_TYPE        = TABLE
        ARCHIVE_STATUS          = IN_QUEUE
        START_TIME              = 1997-10-25T00:00:00.000Z
        STOP_TIME               = NULL
        DATA_SET_RELEASE_DATE   = 2003-06-30
        PRODUCER_FULL_NAME      = "DR. WILLIAM S. KURTH"
        DETAILED_CATALOG_FLAG   = "N"
        DATA_SET_TERSE_DESC     = "
          The Cassini Radio and Plasma Wave Science (RPWS) resampled
          summary key parameter data set includes summary spectral
          information calibrated in units of spectral density for the
          entire Cassini mission."
    
        DATA_SET_DESC           = "
    
    
      Data Set Overview
      =================
        The Cassini Radio and Plasma Wave Science (RPWS) calibrated summary
        key parameter data set includes reduced temporal and spectral
        resolution spectral information calibrated in units of spectral
        density for the entire Cassini mission.  This data set includes
        calibrated values binned and averaged within 1 minute by 0.1 decade
        spectral channels for all times during the mission including the two
        Venus flybys, the Earth flyby, the Jupiter flyby, interplanetary
        cruise, and the entire Saturn tour.  Data for this data set are
        acquired by the RPWS Low Frequency Receiver (LFR), Medium Frequency
        Receiver (MFR), and High Frequency Receiver (HFR).  Data are
        presented in a set of fixed-record-length tables.  This data set is
        intended to provide numerical summary data which can be used in
        conjunction with other Cassini fields and particles key parameter
        data sets to establish trends, select events, or simply as a browse
        data set for the Cassini RPWS archive.  This data set should be
        among the first used by a user of any of the RPWS archive as it will
        lead one to information required to search for more detailed or
        highly specialized products.
    
    
      Parameters
      ==========
        This data set comprises electric and magnetic field spectral
        densities for each sensor, binned and averaged into moderate
        resolution frequency and time bins.  We use 10 spectral channels per
        decade logarithmically spaced in frequency, usually from 1 Hz to 16
        MHz, and a 1-minute time step.
    
    
      Processing
      ==========
        Data in this data set were processed by the use of a number of
        software programs which assemble segmented mini-packets in the raw
        telemetry packets into complete sets, de-compress the data that were
        compressed by one of a number of compression algorithms by the RPWS
        flight software onboard, apply conversion lookup tables or
        algorithms to convert telemetry data numbers into physical units,
        make any corrections required for antenna capacitive loading or
        other effects, bin the measurements into frequency and time bins,
        and then determine the median of all measurements within a bin.
        These data are calibrated using the best calibration tables and
        algorithms available at the time the data were archived.  See
        chapters 5 - 11 of the RPWSCAL document in the DOCUMENT directory
        for details on how the data included in this data set were
        calibrated.  Should a significant improvement in calibration become
        available, an erratum will be noted in the erratum section.  Later
        versions of this data set may contain better calibrations.  It
        should be noted, however, that since measurements from different
        sensors are binned (via finding the median measurement in the bin)
        the resulting spectrum is an amalgamation of different sensors
        oriented in different directions.  Hence, the detailed
        interpretation of this data set is not necessarily straight-
        forward.  If the user is interested in the best calibrated value
        with a minimum of interpretational issues, the Low Rate Full
        resolution data product would be the best source of information.
    
    
      Data
      ====
        The RPWS key parameter data set includes tables of wave spectra as a
        function of time using measurements from each of the various
        receivers of the RPWS, including the LFR, MFR, and HFR.  Each table
        will contain fixed-length records including columns for time and
        spectral densities for each channel.
    
    
      Ancillary Data
      ==============
        Ancillary data included with this data set collection include a
        series of files that describe the modes of the RPWS as a function of
        time and provide a time-ordered listing of Instrument Expanded Block
        (IEB) trigger commands (the mode by which the RPWS is reconfigured).
        Also a detailed description of each of the modes (or IEBs) is
        provided.
    
        Other data which are ancillary to this data set but which are
        archived separately from this collection are the Navigation and
        Ancillary Information Facility's SPICE kernels describing the
        position and attitude of Cassini and various solar system bodies as
        a function of time.
    
    
      Coordinate System
      =================
        The data in this data set are measurements of wave electric and
        magnetic fields measured by the RPWS electric and magnetic sensors.
        These fields are presented as detected by the sensors and are not
        rotated into any other coordinate system.  If desired the SPICE
        kernels can be used with the SPICE toolkit to convert from the
        spacecraft frame to virtually any frame which may be of use in
        analyzing these data.  However, for many purposes, the wave
        amplitudes are extremely useful and may be entirely adequate with no
        coordinate transformations at all.
    
    
      Software
      ========
        Since the data are provided in text files as fully calibrated
        amplitudes, no example software is provided for reading these data.
        However, a platform-independent Java (TM) application is provided in
        EXTRAS/SOFTWARE/KEY_BROWSE.JAR which can read these data and produce
        spectrograms with user-selectable options.  See README.TXT in the
        same directory for further information.
    
    
      Media/Format
      ============
        These data are supplied to the Planetary Data System on DVD-R media
        using formats and standards of the PDS for such media."
    
        CONFIDENCE_LEVEL_NOTE   = "
    
    
      Confidence Level Overview
      =========================
        This data set contains all low rate key parameter data for the
        Cassini RPWS instrument for the intervals described In the product
        label files.  Every effort has been made to ensure that all data
        returned to JPL from the spacecraft are included and that the
        calibration is accurate. A column in each record indicates whether
        the confidence in the data in that record is high (0) or not (9).
    
    
      Review
      ======
        The RPWS calibrated summary key parameter data will be reviewed
        internally by the Cassini RPWS team prior to release to the PDS.
        The data set will also be peer reviewed by the PDS.
    
    
      Data Coverage and Quality
      =========================
        All data in the intervals described in the product label files are
        included, to the best of our knowledge and attempts to determine
        completeness.  In general, the instrument was operated only briefly
        during early tour for the following intervals:
    
        1.  Antenna deployment   1997-10-25T00:00 - 1997-10-26T05:30
        2.  Venus 1 flyby        1998-04-26T12:54 - 1998-05-08T19:21*
        3.  Instrument Checkout  1998-12-30T09:10 - 1999-01-19T05:40
        4.  Venus 2 flyby        1999-06-24T09:08 - 1999-06-24T21:20
        5.  Earth flyby          1999-08-13T17:39 - 1999-09-14T22:20
    
        *Actual interval for science data is much shorter than this.
    
        Beginning in February of 2000 the instrument was operated
        more-or-less continuously; two gaps of the order of six weeks were
        incurred for the purposes of loading new attitude control and
        command and data system flight software, gaps of a few days each
        were incurred approximately twice per year because of Huygens Probe
        testing, and gaps of several days in duration occurred during solar
        conjunction periods prior to 2002. Remaining gaps are due to
        spacecraft anomaly resolution or simply to downlink gaps, some of
        which were imposed by limitations on DSN station availability.
    
    
      Limitations
      ===========
        The only known measurement quality issue is occasional elevated
        noise levels (by a few to 10 dB) in the second band of the MFR.
        During tour, it is anticipated that data from the Waveform Receiver
        (WFR) sometimes refered to as the medium frequency digital receiver
        (MFDR) can be substituted for these in the full resolution data
        product (RPWS LOW RATE FULL)."
    
      END_OBJECT              = DATA_SET_INFORMATION
    
      OBJECT                  = DATA_SET_TARGET
        TARGET_NAME             = VENUS
      END_OBJECT              = DATA_SET_TARGET
    
      OBJECT                  = DATA_SET_TARGET
        TARGET_NAME             = EARTH
      END_OBJECT              = DATA_SET_TARGET
    
      OBJECT                  = DATA_SET_TARGET
        TARGET_NAME             = JUPITER
      END_OBJECT              = DATA_SET_TARGET
    
      OBJECT                  = DATA_SET_TARGET
        TARGET_NAME             = SATURN
      END_OBJECT              = DATA_SET_TARGET
    
      OBJECT                  = DATA_SET_TARGET
        TARGET_NAME             = SOLAR_SYSTEM
      END_OBJECT              = DATA_SET_TARGET
    
      OBJECT                  = DATA_SET_HOST
        INSTRUMENT_HOST_ID      = CO
        INSTRUMENT_ID           = RPWS
      END_OBJECT              = DATA_SET_HOST
    
      OBJECT                  = DATA_SET_REFERENCE_INFORMATION
        REFERENCE_KEY_ID        = "GURNETTETAL2003"
      END_OBJECT              = DATA_SET_REFERENCE_INFORMATION
    
    END_OBJECT              = DATA_SET
    END
    
    
    Data Availability: (less detail)
    RPWS_KEY

    1997 298 - 299   
    1998 116 - 116   
    1998 364 - 365   
    1999 001 - 011   
    1999 015 - 019   
    1999 175 - 175   
    1999 227 - 257   
    2000 037 - 065   
    2000 113 - 116   
    2000 118 - 120   
    2000 123 - 125   
    2000 127 - 127   
    2000 129 - 137   
    2000 141 - 145   
    2000 153 - 209   
    2000 248 - 251   
    2000 253 - 366   
    2001 001 - 031   
    2001 036 - 130   
    2001 138 - 155   
    2001 162 - 209   
    2001 211 - 213   
    2001 217 - 242   
    2001 244 - 265   
    2001 268 - 278   
    2001 280 - 318   
    2001 325 - 365   
    2002 001 - 019   
    2002 021 - 049   
    2002 051 - 105   
    2002 107 - 118   
    2002 121 - 138   
    2002 140 - 144   
    2002 146 - 219   
    2002 223 - 240   
    2002 244 - 249   
    2002 251 - 257   
    2002 259 - 271   
    2002 274 - 328   
    2002 332 - 365   
    2003 001 - 039   
    2003 105 - 106   
    2003 109 - 132   
    2003 136 - 142   
    2003 144 - 271   
    2003 273 - 336   
    2003 338 - 338   
    2003 340 - 341   
    2003 343 - 365   
    2004 001 - 060   
    2004 064 - 186   
    2004 194 - 366   
    2005 001 - 006   
    2005 015 - 365   
    2006 001 - 365   
    2007 001 - 093   
    2007 095 - 254   
    2007 258 - 279   
    2007 291 - 365   
    2008 001 - 366   
    2009 001 - 071   
    2009 077 - 123   
    2009 125 - 365   
    2010 001 - 306   
    2010 319 - 337   
    2010 339 - 365   
    2011 001 - 365   
    2012 001 - 293   
    2012 303 - 315   
    2012 317 - 343   
    2012 345 - 366   
    2013 001 - 365   
    2014 001 - 127   
    2014 129 - 365   
    2015 001 - 365   
    2016 001 - 066   
    2016 068 - 357   
    2017 027 - 027   
    2017 035 - 117   
    2017 120 - 258   

    Cassini TRAJ home: http://saturn.jpl.nasa.gov/home/index.cfm

    Cassini Trajectory Information at JPL: http://saturn.jpl.nasa.gov/operations/saturn-tour.cfm

    The TRAJ Key Parameters file contain information related to the position of Cassini and Titan in different coordinate systems. The CASS data file contains the position and velocity of the Cassini spacecraft in both Saturn centered (KSM and KG) and Titan centered (IAU Titan) coordinate systems. The TITN key parameter file contains the location of Titan relative to Saturn in two different coordinate system (KSM and KG).

    DATA Types: CASS TITN

    More Detailed Information

    General


    The TRAJ Key Parameters file contain information related to the position of Cassini and Titan in different coordinate systems. The CASS data file contains the position and velocity of the Cassini spacecraft in both Saturn centered (KSM and KG) and Titan centered (IAU Titan) coordinate systems. The TITN key parameter file contains the location of Titan relative to Saturn in two different coordinate system (KSM and KG).


    CASS: Trajectory of the Cassini Spacecraft


    Definitions:

    KG = KronoGraphic (IAU2000 Saturn Fixed)
    KSM = Kronocentric Solar Magnetic
    T = Titan centered coordinate system (IAU2000 Titan Fixed)

    Column Definitions:

    Time(UTC) X(KG) Y(KG) Z(KG) Vx(KG) Vy(KG) Vz(KG) X(KSM) Y(KSM) Z(KSM) Vx(KSM) Vy(KSM) Vz(KSM) X(T) Y(T) Z(T) Vx(T) Vy(T) Vz(T)

    Units:

    yyyy-dddThh:mm:ss.sss km km km km/s km/s km/s km km km km/s km/s km/s km km km km/s km/s km/s

    Sample:

    2003-244T00:00:30.000  -130267660.000004   -42565535.066882   -40428334.459688       -6966.853507       21337.508167           1.510746    75727920.636334  -120910930.112086    -7859214.981039          -2.836920           4.389266           0.290210    26985668.213380  -134604306.408065   -40140266.599779        -615.186070        -112.720408           1.500482
    2003-244T00:01:30.000  -130679373.489513   -41283252.682989   -40428243.815117       -6756.819201       21404.893976           1.510746    75727695.613691  -120910699.121409    -7859227.741065          -2.836918           4.389268           0.290212    26948756.170174  -134611064.571971   -40140176.577045        -615.215512        -112.551812           1.500482
     

    TITN: Trajectory of the Titan


    Definitions:

    KG = KronoGraphic (IAU2000 Saturn Fixed)
    KSM = Kronocentric Solar Magnetic

    Column Definitions:

    Time(UTC) X(KG) Y(KG) Z(KG) Vx(KG) Vy(KG) Vz(KG) X(KSM) Y(KSM) Z(KSM) Vx(KSM) Vy(KSM) Vz(KSM)

    Units:

    yyyy-dddThh:mm:ss.sss km km km km/s km/s km/s km km km km/s km/s km/s

    Sample:

    2003-245T00:00:30.000     1063372.793758      667556.455523        6903.216333         106.489834        -169.550743          -0.020491     -829214.914363     -854029.827198     -399345.282012           3.290819          -4.002582           1.592532
    2003-245T00:01:30.000     1069713.424333      657352.987754        6901.986627         104.862905        -170.562255          -0.020499     -829017.839510     -854269.491034     -399249.867362           3.291771          -4.001601           1.592990
    

    More Detailed Information:


    Data Availability: (less detail)
    TRAJ_CASS

    2003 244 - 365   
    2004 001 - 366   
    2005 001 - 365   
    2006 001 - 365   
    2007 001 - 365   
    2008 001 - 366   
    2009 001 - 365   
    2010 001 - 365   
    2011 001 - 365   
    2012 001 - 366   
    2013 001 - 365   
    2014 001 - 365   
    2015 001 - 365   
    2016 001 - 366   
    2017 001 - 270   
    TRAJ_TITN

    2003 244 - 365   
    2004 001 - 366   
    2005 001 - 365   
    2006 001 - 365   
    2007 001 - 365   
    2008 001 - 366   
    2009 001 - 365   
    2010 001 - 365   
    2011 001 - 365   
    2012 001 - 366   
    2013 001 - 365   
    2014 001 - 365   
    2015 001 - 365   
    2016 001 - 366   
    2017 001 - 270   

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