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Galileo Probe Raw Data Sets (PDS)

NSSDCA ID: PSPA-00499

Availability: Archived at NSSDC, accessible from elsewhere

Description

This description was generated automatically using input from the Planetary Data System.

Data Set Overview

From [SEIFFETAL1996]: The Galileo Probe Atmospheric Structure Instrument (ASI) measured state properties of Jupiter's atmosphere from nanobar pressure levels to a final pressure of ~24 bars. The depth reached in the probe's parachute descent, calculated from measured temperatures and pressures assuming hydrostatic equilibrium, was ~160 km or 0.22% of the radius of Jupiter. Velocities during descent decreased from ~400 m/s at parachute deployment to 156 m/s in the first 100 s, to ~48 m/s at the 3-bar level, and to ~30 m/s at loss of signal. Temperatures measured in parachute descent had an accuracy of ~1 K and a dispersion on the order of the digital resolution (0.12 K). Comparison with the Orton model indicates that the atmosphere is close to a dry adiabat over this pressure range. Water condensation, expected above the 5-bar level if the oxygen mole fraction is solar (0.0017) and above the 4-bar level for the low water abundance detected by the neutral mass spectrometer (~0.2 of the solar abundance value), has major effects on the temperature variation. Temperatures following the dry adiabat at these levels confirm the low water abundance and are consistent with the absence of a detectable water cloud. Deviations from the adiabat between 1 and 3 bars, which were initially interpreted as a stable layer in the tenuous cloud above 1.6 bars and an unstable layer below the cloud, now are believed to reflect departures from preflight pressure sensor calibrations resulting from unanticipated variations in the probe's internal temperature.

Data Set Overview

A total of seven data sets are used to derive the wind profile. These include two trajectory data files (probe and orbiter), three frequency data files including the 'quicklook' data set comprising 1/2 resolution frequency data from the orbiter CDS, and two data files containing the full tape recorder (SDR) data. Additionally, the probe descent trajectory data are supplemented with probe descent velocity/altitude/pressure/time data from the Atmospheric Structure Instrument. Finally, the Jovian atmospheric structure, based on measurements by the Atmospheric Structure Instrument, is included in ASI4ATM.TAB. Reference Times --------------time of entry (UT): 22:04:43.752 time of Minor Frame Zero (UT at the probe): 22:07:30.265 time of Minor Frame Zero (UT at the orbiter): 22:07:30.965 time of Lock (UT at the orbiter): 22:08:30.693 time of Loss of Lock (UT at the orbiter): 23:06:09 time between entry and Minor Frame Zero at the probe: 166.513 seconds time between entry and lock at the orbiter: 226.941 seconds time between Minor Frame Zero and lock at the orbiter: 59.728 seconds time between entry and loss of lock at the orbiter: 3,685.25 seconds total data (total time of lock): 57 minutes, 38.31 seconds = 3,458.31 seconds Total data points (frequencies): 5,015 out of a possible 5,174 total missing frequencies: 5,174 - 5,015 = 159 Note 1: Minor Frame Zero is the start time of the first minor frame of data in probe descent mode. This is the probe mission reference time. It differs between the probe and orbiter due to the propagation time between the probe and orbiter of about 0.7 seconds. The use of one time or the other (relative to the probe or the orbiter) depends on whether the instantaneous times of each frequency measurement and the trajectory parameters are referenced to times at the probe or the orbiter. Since the probe/orbiter trajectories, as well as the winds, are referenced to times at the probe, Minor Frame Zero at the probe is used rather than at the orbiter. Note 2: Lock is the time (UT) at which the orbiter locks onto the probe signal and starts recording probe science data. Data ==== Data files: CRS (Orbiter trajectory, ASCII): orbtrtrj.tab PSTF (Probe trajectory, ASCII): probetrj.tab CDS (Tape Recorder, half resolution frequency, ASCII): rsf0117a.adj SDR (Probe frequency data, ASCII): sdr0530a.tab SDR (Probe frequency data, ASCII): radio.tab ASI (Probe trajectory data from ASI, ASCII): asi2ref.tab Atmospheric Structure Data (ASCII): asi4atm.tab Frequency data: The frequency data sets come in two different forms. The 'Quick-Look' data are half-resolution and comprise probe radio link frequencies stored in the orbiter CDS every 4/3 seconds. These data files, designated as rsf (radio science frequencies) are described in more detail below. The System Data Record (SDR) data are from the tape recorder with a sampling frequency of 1.5 Hz (one sample every 2/3 seconds). The SDR data are described below. The probe and orbiter data files (PSTF and CRS, respectively) provide the probe and orbiter trajectories in time from entry. The PSTF file lists the probe position and velocity as a function of time from probe entry (defined to be the time of probe altitude equal to 450 km above the one bar reference surface). The probe descent trajectory is given in x,y,z,xdot,ydot,zdot in EME50 coordinates (defined below). The orbiter trajectory is also listed as x,y,z,xdot,ydot,zdot in EME50 coordinates as a function of time past 1950 in ephemeris time. CRS - Orbiter Trajectory Data File, ASCII The orbiter trajectory, provided by the Galileo Navigation team at the Jet Propulsion Laboratory, is contained in a data file called a CRS file. The CRS data set provides the EME50 coordinates (x,y,z;xdot,ydot,zdot) of the center of Jupiter in an orbiter-centered system. The CRS file also provides auxiliary data such as GM, and the equatorial and polar radii for Jupiter. The times for the orbiter trajectory are given in year, day, hour, minute, second, and millisecond past 1950 in ephemeris time. The orbiter trajectory is converted from the spacecraft-centered EME50 coordinates to a Jupiter-centered JPPM (Jupiter Pole and Prime Meridian) frame. To make this conversion, the unit vectors in the direction of Jupiter's rotation axis (x_pole,y_pole,z_pole) and prime meridian (x_pm,y_pm,z_pm) in EME50 coordinates must be known. These are provided in the probe trajectory file PSTF. PSTF - Probe Trajectory Data File, ASCII The Probe System Trajectory File (PSTF) provides the nominal descent profile of the probe from entry to the end of the descent mission. The PSTF file is generated by the ATMINT program, a key element of JPL's RLINK program set. The PSTF file is an ASCII file that contains 1) a header containing run identification information; 2) a listing of major program parameter values, including a table of probe aerodynamic coefficients, and 3) a descent trajectory profile which lists the probe's inertial and atmosphere relative motion in Jupiter's atmosphere as a function of time after entry. At the time of parachute deployment the profile is interrupted by a second aerodynamic characteristics table. This is followed by a listing of the probe positional and velocity vectors, the unit vectors in the vertical, west, and north directions at the probe, and the probe altitude relative to the one bar level, all as a function of time (seconds after entry). The probe position and velocity components are given in Jupiter-centered EME50 coordinates. Auxiliary data supplied in the PSTF file include 1) the probe entry time both in year, day of year, hour, minutes, and seconds in ephemeris time, and the number of seconds past 1950 again in ephemeris time; 2) the unit vectors in the direction of Jupiter's pole (z-axis), and the intersection between the prime meridian and Jupiter's equator (y-axis) in EME50 coordinates; 3) the atmosphere model (nominal Orton III); 4) Gravitational parameters (GM, J_2, J_4); 5) the polar and equatorial radii; 6) the planetary flattening; and 7) the system III rotation period of Jupiter. An x-axis is generated by standard techniques to complete the right-handed coordinate system. It should be noted that, although the probe entry time is provided in the PSTF file, for purposes of the wind retrieval the entry time is input separately, and can therefore be altered without the need for regenerating an entirely new PSTF data set. The PSTF file used (PSTF-OD126_1s) provides the probe descent trajectory in 1 second increments and includes the effect of the late parachute deployment. Once the probe trajectory is converted from the Jupiter-centered EME50 coordinates to the JPPM reference frame, the probe positions and velocities are generated as a function of time after entry in a radius, latitude, longitude coordinate system. CDS (RSF) Frequency Data, ASCII Due to the failure of the high gain antenna to deploy and concerns about the possible failure of the orbiter tape recorder, the probe data were stored in the memory of the orbiter Command and Data Subsystem as a backup. The CDS data stored in the CDS were at half resolution (every other time point) and therefore provided a frequency measurement every 4/3 seconds. The CDS data are an ASCII file of NCO frequency vs. time from lock and were used for the early wind analysis. The CDS (half-resolution) data are contained within the data file rsf0117a.adj. The 'adj' indicates that the data set is adjusted by removal of spurious frequency measurements and missing data. The first several lines of rsf0117a.adj are given below: 0.000 95:341:22: 8:30.693 1 30 96 C8 432029.71 1.333 95:341:22: 8:32. 26 1 30 96 75 432018.45 2.667 95:341:22: 8:33.360 1 30 96 1B 432006.24 4.000 95:341:22: 8:34.693 1 30 95 BE 431993.62 5.333 95:341:22: 8:36. 26 1 30 95 68 431981.95 Column one gives the time after lock (seconds) and the last column gives the NCO frequency in Hz. SDR Frequency Data (Tape Recorder) There are two SDR data sets presented in this archive. The first, designated sdr0530a.tab, is the probe frequency raw data as an ASCII data file. This file has several data outages of varying lengths, and several individual missing frequency measurements. Many of these missing measurements were filled in using the CDS data set. Including housekeeping and radioscience, the probe data were stored on the orbiter tape recorder for later playback to the ground. The probe signal frequency, measured every 2/3 seconds, as well as the other probe science and engineering data measured throughout the probe mission, was delivered in the form of binary System Data Records. The data file sdr0530a.tab is an ASCII file that was converted from binary for further analysis. Although the probe signal frequencies were measured every 2/3 seconds, some gaps existed in the data due to corrupted data, DSN outages, and possibly several bad spots on the tape recorder tape. Many of these gaps were filled by the CDS data. Out of 5,174 possible frequency measurements there are only 159 missing points, none consecutive. The SDR (tape-recorder) data are contained within data file radio.tab and include (where necessary) half-resolution data from the CDS file rsf0117a.adj to fill gaps in the data, and corrections for the timing errors. radio.tab is an ASCII file that lists NCO frequency vs. time from lock (seconds). The first several lines of radio.tab are given below. The columns are time from lock (seconds) and NCO frequency (Hz): .000 432029.712 .667 432024.013 1.334 432018.451 2.000 432012.481 Ancillary Data ============== Data from the probe Atmospheric Structure Instrument are used to supplement the Doppler wind analysis. Of primary importance are the probe descent velocity, and radius/altitude (above/below the one bar reference surface at the given latitude) vs. pressure/time. These data are included in the file asi2ref.tab. The first several lines of asi2ref.tab are provided below. The columns are column 1: time from minor frame zero (seconds) column 2: unused column 3: probe altitude (km above 1 bar) column 4: probe radial velocity (m/s) column 5: unused column 6: unused column 7: unused column 8: Probe latitude (planet-centered) column 9: Probe longitude at initial time point only column 10: unused column 11: unused column 12: unused 30.1600 0.0 16.000 98.747 0.0 0.0 0.0 6.41 359.468 0.0 0.0 0.0 50.4700 0.0 14.031 95.168 0.0 0.0 0.0 6.41 0.0 0.0 0.0 0.0 71.1400 0.0 12.098 91.866 0.0 0.0 0.0 6.41 0.0 0.0 0.0 0.0 91.2600 0.0 10.281 88.709 0.0 0.0 0.0 6.41 0.0 0.0 0.0 0.0 112.200 0.0 8.4539 85.822 0.0 0.0 0.0 6.41 0.0 0.0 0.0 0.0 134.400 0.0 6.5777 83.206 0.0 0.0 0.0 6.41 0.0 0.0 0.0 0.0 157.460 0.0 4.6867 80.797 0.0 0.0 0.0 6.41 0.0 0.0 0.0 0.0 The initial time point is 30.60 seconds after Minor Frame Zero, and the final time point is 3,422.44 seconds after Minor Frame Zero. Note: The total data used in the Doppler Wind Analysis is limited by the duration of the ASI data. Therefore, although the total time of lock is 3,458.31 seconds, only 3,361.33 seconds of data are used for the wind retrieval due to the lack of ASI data beyond 3,422.44 seconds after Minor Frame Zero. Other Data Sets Provided ======================== FRED.TAB This ASCII file contains the frequency residuals for the Galileo Probe Doppler Wind Experiment prior to the wind measurements. The columns are Time from Entry in seconds Pressure at probe location (bar) Frequency Residuals before the wind retrieval (Hz) This file contains 5043 rows. The initial time point is 1995-12-07 22:08:31 (UT), corresponding to the initial Time from Entry of 227.3333 seconds. The final time point is 23:04:32 (UT), corresponding to Time from Entry of 3,588.6667 seconds. Note: the total time in this file (5043 time points) is 3,588.6667 - 227.3333 seconds = 3,361.33 seconds. This is less than the total time of lock provided above (3,458.31 seconds) and is due to the fact that data from the Atmospheric Structure Instrument was used to generate the probe descent profile (asi2ref.tab). Therefore, the total data are limited not by the time of loss of lock, but by the time at which the data provided by the ASI instrument team ended. The first several rows are shown below: 227.3333 0.5648 0.0000 228.0000 0.5664 0.3178 228.6667 0.5680 0.4498 229.3333 0.5696 0.2558 RESID.TAB This ASCII file contains data for the Galileo Probe Doppler Wind Experiment, including time from entry, time from link lock, altitude, pressure, and frequency residuals after the wind retrieval. The columns are Time from entry (seconds) Time from link lock (seconds) Altitude above 1 bar (km) Pressure at probe location (bar) Frequency Residuals after the wind retrieval (Hz) This file contains 5043 rows. The initial time point is 1995-12-07 22:08:31 (UT), corresponding to the initial Time from Entry of 227.3333 seconds. The final time point is 23:04:32 (UT), corresponding to Time from Entry of 3,588.6667 seconds. Note: the total time in this file (5043 time points) is 3,588.6667 - 227.3333 seconds = 3,361.33 seconds. This is less than the total time of lock provided above (3,458.31 seconds) and is due to the fact that data from the Atmospheric Structure Instrument was used to generate the probe descent profile (asi2ref.tab). Therefore, the total data are limited not by the time of loss of lock, but by the time at which the data provided by the ASI instrument team ended. The first several rows are shown below: 227.3330 0.392330 13.3990 0.5648 0.00000 228.0000 1.05900 13.3380 0.5664 0.37720 228.6670 1.72567 13.2770 0.5680 0.56510 229.3330 2.39233 13.2160 0.5696 0.42640 WIND.TAB This ASCII file contains wind data from the Galileo Probe Doppler Wind Experiment, including time from entry, time from lock, temperature, pressure and wind. The columns are Time from entry (seconds) Time from link lock (seconds) Temperature (K) Pressure at probe location (bar) Wind (m/s) This file contains 5043 rows. The initial time point is 1995-12-07 22:08:31 (UT), corresponding to the initial Time from Entry of 227.3333 seconds. The final time point is 23:04:32 (UT), corresponding to Time from Entry of 3,588.6667 seconds. Note: the total time in this file (5043 time points) is 3,588.6667 - 227.3333 seconds = 3,361.33 seconds. This is less than the total time of lock provided above (3,458.31 seconds) and is due to the fact that data from the Atmospheric Structure Instrument was used to generate the probe descent profile (asi2ref.tab). Therefore, the total data are limited not by the time of loss of lock, but by the time at which the data provided by the ASI instrument team ended. The first several rows are shown below: 227.3330 0.39200 138.1107 0.5648 86.54214 228.0000 1.05900 138.2380 0.5664 86.52588 228.6670 1.72600 138.3654 0.5680 86.51108 229.3330 2.39200 138.4927 0.5696 86.49774 Coordinate System ================= EME50 - Earth Mean Equator and Equinox of 1950 Coordinates The EME50 coordinate system is an inertial (non-rotating) cartesian coordinate frame. It is defined by the Earth's mean equator, Earth's vernal equinox, and Earth's rotation axis. The positive x-axis is directed towards the Earth's mean vernal equinox of date; the z-axis is aligned with Earth's mean rotation axis, and the y-axis is made to complete the right-handed coordinate frame. The epoch is 1950 (December 21, 1949 at 22:09:07 UT). Planetographic/Planetocentric Latitudes Planetographic/planetocentric latitudes are measured north (positive) and south (negative) of the equator. The planetographic latitude of a point on the reference surface is the angle between the equatorial plane and the normal to the surface at that point. The planetocentric latitude of a point is the angle between the line connecting the point to the center of mass and the equator [DAVIESETAL1983]. System III Longitudes The Jupiter System III longitudes are defined by the rotation of Jovian decimetric and decametric radio noise, presumably co-rotating with Jupiter's magnetic field and core. [RIDDLE&WARWICK1976]. JPPM - Jupiter Pole and Prime Meridian Coordinates The Jupiter Pole/Prime Meridian system is an inertial cartesian coordinate system centered on Jupiter's center. The z-axis is along Jupiter's rotation axis, the y-axis is defined by the unit vector through the intersection of the system III (1965) Prime Meridian and the Jovian equator in EME50 at the epoch of probe entry, and the x-axis completes the right-handed coordinate system.

Data Set Overview

The Galileo Probe Energetic Particles Investigation (EPI) Raw Data Set contains two tables of the EPI raw data values sorted by sampling time. The counter table contains the raw counter values as measured and the countrate table contains the countrates as derived from counter values, but without any correction. The tables are split into omnidirectional and sectorized data. The distance to Jupiter is given in Jupiter radii, Rj, and was derived from the Probe trajectory data. The time of probe entry is taken to be 1995-12-07T22:04:44Z when the probe reached an altitude of 450 km above the 1 bar pressure level. Parameters ========== The counter values are numbers without unit, while the countrates are given in counts per second. The sampling time for the omnidirectional channels E12, E22, E32, P12, P31, P32 was 17.145 s, for the omnidirectional HE2 channel it was 46.72 s, for the omnidirectional channel HVY in sample 1 - 4 it was 128 s and for the omnidirectional channels HVY1-HVY4 in sample 5-15 it was 64 s. For the sectorized channels E11S, E21S, E31S, P11S, P21S, P22S the sampling time was 2.143 s and for the sectorized HE1S channel it was 11.43 s. 1 Rj = 71372 km. This value for Rj was selected to be consistent with the value used by the Pioneer 10 and 11 investigations. The Pioneers were the only other spacecraft to fly to low jovian altitudes. Users should be cautioned when comparing data sets organized by distance when the units provided are jovian radii. Many different values have been selected by the Pioneer, Voyager, Ulysses, and Galileo teams. In particular, the value used here is inconsistent with the value widely adopted by orbiter scientists who use the value 71492 km. Data ==== The EPI RAW DATA SET comprises five tables: (1) Counter Table - Omnidirectional (2) Counter Table - Sector (3) Countrate Table - Omnidirectional (4) Countrate Table - Sector (5) Housekeeping Table (1-2) Counter Tables These tables contain the raw counter values as measured. The data are sorted by their distance to Jupiter given in Jupiter radii, Rj. (3-4) Countrate Tables These tables contain the raw countrates derived from the counter values. The data are sorted by their distance to Jupiter given in Jupiter radii, Rj. (5) Housekeeping Table This table contains the detector leakage currents and the temperature of the EPI sensor. The data are sorted by their distance to Jupiter given in Jupiter radii, Rj. Ancillary Data ============== Trajectory and timing information were obtained from the Galileo Project. Coordinate System ================= The data are presented according to the radial distance of the probe to Jupiter as given by the project office.

Data Set Overview

From [VONZAHN&HUNTEN1996]: More than 99.5 mole percent of the jovian atmosphere consists of H2 and He. Hence, to a first approximation, this atmosphere can be considered to be a binary gas mixture, for which the mole fraction q(He) can be derived from the ratio of refractive indices q(He) = (n(H2) - n(s)) / (n(H2) - n(He)) where n(He) is the refractive index of He, n(H2) is the refractive index of H, and n(s) is the refractive index of the sample gas (jovian gas). The word 'sample' is used because the refractive index of this jovian gas is measured inside the HAD instrument and at sample gas pressures and temperatures that differ from conditions in the ambient jovian atmosphere. Parameters ========== From [VONZAHN&HUNTEN1992]: Definitions for abundance measures ----------------------------------------------------------------------------- 'Mass fraction' N_Hm_H + 2N_H2m_H Hydrogen mass fraction X is equivalent to --------------------------SUM of (N_jm_j) for all j's N_Hem_He Helium mass fraction Y is equivalent to --------------------------SUM of (N_jm_j) for all j's Mass fraction of all other elements Z is equivalent to 1 - X - Y with N_i the number density of particles of type i; m_i mass of a particle of type i 'Mole fraction' N_i (mixing ratio) q_i is equivalent to -----------------------SUM of (N_j) for all j's with SUM of (q_j) for all j's = 1 N_He In particular at Jupiter q_He is approximately -----------------------N_H2 + N_He 'Abundance ratio' of N_He helium/hydrogen R_He is equivalent to -----------------------N_H2 ----------------------------------------------------------------------------- Processing ========== Details can be found in [VONZAHN&HUNTEN1996]. Data ==== The data included here were provided to the PDS by Ulf Von Zahn as a one page FAX. No attempt was made by the instrument team to provide any other data or information such as the interference fringe count.

Data Set Overview

Data from this instrument appear to have been lost due to the death of Co-Investigator Klaus Rinnert. Please refer to the publications below for results from this instrument.

Data Set Overview

Description of nephelometer files in the data bank: This file describes the data obtained by the Galileo Probe Nephelometer during the descent into the Jupiter atmosphere on December 7, 1995. The total time of data acquisition was less than two hours before the destruction of the probe in the Jupiter atmosphere. The Nephelometer measured light scattering at 900 nm wavelength at five angles in order to determine properties of aerosol particles and clouds encountered during descent. References describing the instrument include 1. Ragent, B., C. A. Privette, P. Avrin, J. G. Waring, C. E. Carlston, T. C. D. Knight and J. P. Martin, Galileo Probe Nephelometer Experiment, Space Science Reviews, 60, 179-201, 1992. [RAGENTETAL1992] 2. Ragent, B., D. S. Colburn, P. Avrin and K. A. Rages, Results of the Galileo Probe Nephelometer Experiment, Science, 272, 854-856, 1996. [RAGENTETAL1996] 3. Ragent, B., D. S. Colburn, K. A. Rages, T. C. D. Knight, P. Avrin, G. S. Orton, P. A. Yanamandra-Fisher and G. W. Grams, The Clouds of Jupiter: Results of the Galileo Jupiter Mission Probe Nephelometer Experiment, Journal of Geophysical Research, 103, 22891-22909, 1998. [RAGENTETAL1998] The data are in tabular form in ASCII format, and thus can be read easily by FORTRAN (or similar) programs. There are 21 files. Each starts out with a header in ASCII which describes the content of the columns and which a FORTRAN program should skip over before reading the data. The following are the 24 data files in the volume: File 1 - raw.dat Raw data. This is the hexadecimal information from the probe. A description of this file follows this table of contents. File 2 - ptz.dat Probe Descent Data. Pressure, temperature and altitude. File 3 - elecoffs.dat Electronic Offsets, Counts. An offset measurement made periodically. File 4 - srcalign.dat Source Monitors and Alignment Detector Readings, Counts. File 5 - tempvolt.dat Forward, Backward and Electronics Temperature Sensor Readings, in Degrees C, and Voltage Monitor, in Counts. File 6 - gain.dat Gain of 16 Degree Channel Electronics. File 7 - contam.dat Contamination Channel Readings, Counts. File 8 - scatter.dat Scatter Data, Counts. File 9 - fittemp.dat Fitted Temperature Profiles, Fitted to a Ninth Order Polynomial File 10 - xsec11.dat Cross Sections with No Adjustment of Baseline and Using Pre-Launch Calibration Data Extrapolated to Cover Out-of-Range Temperatures. File 11 - xsec12.dat Cross Sections with No Adjustment of Baseline and Using Both Pre-Launch Calibration Data and Post-Encounter Test Data to Cover Out-of-Range Temperatures Experienced during Probe Descent. File 12 - xsec21.dat Cross Sections with Adjustment of Baseline to Zero at Measurement Number 14 (p = 0.510 bars) and Using Pre-Launch Calibration Data Extrapolated to Cover Outof-Range Temperatures Experienced during Probe Descent. File 13 - xsec22.dat Cross Sections with Adjustment of Baseline to Zero at Measurement Number N=14 (p=0.510 bars) and Using Both Pre-Launch Calibration Data and Post-Encounter Test Data to Cover Out-of-Range Temperatures Experienced during Probe Descent. File 14 - xsec31.dat Cross Sections with Adjustment of Baseline to Zero at Measurement Number 24 (p = 0.627 bars) and Using Pre-Launch Calibration Data Extrapolated to Cover Outof-Range Temperatures Experienced during Probe Descent. File 15 - xsec32.dat Cross Sections with Adjustment of Baseline to Zero at Measurement Number N=24 (p=0.627 bars) and Using Both Pre-Launch Calibration Data and Post-Encounter Test Data to Cover Out-of-Range Temperatures Experienced during Probe Descent. File 16 - xsec41.dat Cross Sections with Adjustment of Baseline to Zero at Measurement Number 60 (p = 1.345 bars) and Using Pre-Launch Calibration Data Extrapolated to Cover Out-of-Range Temperatures Experienced during Probe Descent. File 17 - xsec42.dat Cross Sections with Adjustment of Baseline to Zero at Measurement Number N=60 (p=1.345 bars) and Using Both Pre-Launch Calibration Data and Post-Encounter Test Data to Cover Out-of-Range Temperatures Experienced during Probe Descent. File 18 - xsec51.dat Cross Sections with Adjustment of Baseline to Zero at Measurement Number 69 (p = 1.621 bars) and Using Pre-Launch Calibration Data Extrapolated to Cover Out-of-Range Temperatures Experienced during Probe Descent. File 19 - xsec52.dat Cross Sections with Adjustment of Baseline to Zero Both at Measurement Number N=69 (p=1.621 bars) and Using Pre-Launch Calibration Data and Post-Encounter Data Test to Cover Out-of-Range Temperatures Experienced during Probe Descent. File 20 - xsec61.dat Cross Sections with Adjustment of Baseline to Zero at Measurement Number 117 (p = 3.603 bars) and Using Pre-Launch Calibration Data Extrapolated to Cover Out-of-Range Temperatures Experienced during Probe Descent. File 21 - xsec62.dat Cross Sections with Adjustment of Baseline to Zero at Measurement Number N=117 (p=3.603 bars) and Using Both Pre-Launch Calibration Data and Post-Encounter Test Data to Cover Out-of-Range Temperatures Experienced during Probe Descent. File 22 - senstemp1.dat Sensitivities for each scatter channel, normalized to 1.000 at 15C, and extrapolated from pre-launch tests on the Flight Unit. File 23 - senstemp2.dat Sensitivities from pre-launch tests on the Flight Unit, normalized to 1.000 at 15 C, and modified using post-encounter data. File 24 - baseoffs.dat Baseline offsets versus temperature measured with the flight unit in the laboratory. File 1 description File 1 contains all of the Nephelometer data transmitted back during the encounter, in hexadecimal form. They were taken directly from the file NEP0701A.SDM, sent from the project office in July 1996. Column 1 has the line number. Each nephelometer frame is identified by a block of 20 lines beginning with the sync word EB 90 followed by the nephelometer frame number in hexadecimal format. Since a nephelometer frame is composed of data from 20 consecutive spacecraft frames, frame number zero contains data from lines 1 through 20, and the frame number for later data is obtained by the integer division of ( line number - 1 ) by 20. Useful data ended at line number 878, and two lines of zeros have been added to complete nephelometer frame 43. As an aid to understanding hexadecimal format, the following examples are shown: Hexadecimal frame numbers 9, A, F, 10, 1A, and 20 have the decimal equivalent 9, 10, 15, 16, 26, and 32. Column 3 contains the number 5 for A string data and 6 for B string data. The file NEP0701A.SDM contains both, and where they overlap, the data is identical, except for a few lines where it is obvious which choice should be made. This data set contains only A string data, because it is a complete set and where B string data exists there is no reason for preferring it over the A string data. Column 2 shows in decimal notation the probe minor frame number transmitted by the probe, cycling from 0 through 63. The minor frame number, and the date and time of transmission, are not essential to interpreting the nephelometer data, since the timing of the measurements is asynchronous with the time of transmission. The first minor frame with nephelometer data is minor frame number 1. Columns 5 through 10 are the Universal Time and date assigned to each minor frame. Columns 5 and 6 represent December 7, 1995. Columns 7 and 8 give the minute and hour, in that order, so that for example the numbers 7, 16 represent 2207 U.T. Columns 9 and 10 give the seconds and milliseconds. The first digit of column 10 generally increases by 1 for each line because the minor frames were transmitted at intervals of very nearly 4 seconds. After every 15 lines, column 7 is expected to increase by one, representing an addition of one minute. The remaining columns (11 through 15) contain the nephelometer data. Every twenty lines contains one nephelometer frame, the start of which is identified by a code word EB 90. The next two digits comprise the nephelometer frame number, supplied by the nephelometer clock, beginning with frame 0 at startup and ending at frame 43 (hexadecimal notation 2B). Since the data set is complete, the frame numbers are found where the index is 1, 21, 41, etc., with the frame number equaling (index - 1)/20. The first several words comprise the engineering data for the frame and they are followed by the words for the nephelometer measurements. In the hexadecimal printout, a frame contains 100 words of 8 bit length. To unpack the data, we have strung the words together to recover the original group of 800 binary bits, and then extracted the 10 bit nephelometer words along with the 8 and 2 bit housekeeping data. Rollover corrections had to be applied to some of the housekeeping data when the analog signals representing temperature, etc., exceeded the expected range of the analog to digital converter. The unpacked data, in counts, are shown in Files 3 through 8. File 2 relates the time of each measurement to the atmospheric pressure and temperature and the probe altitude as determined by the ASI experiment. Thus the data in the remaining files are labelled by atmospheric pressure in order to relate nephelometer findings to the atmospheric environment. Files 9 through 21 are cross sections computed according to the parameters described in the headings. (See reference 3)

Data Set Overview

The Galileo Probe Net Flux Radiometer (NFR) measured net and upward radiation fluxes in Jupiter's atmosphere between about 0.44 bars and 14 bars, using five spectral channels to separate solar and thermal components. The instrument used an optical head extending through the probe wall to obtain views of the Jovian atmosphere. It sampled upward and downward radiation fluxes with a single 40 degree (full angle) conical field of view chopped between directions +/- 45 degrees from horizontal. Parameters ========== This data set includes the Experimental Data Record (EDR) file, raw instrument counts, engineering data, corrected fluxes, calibration information, and some ancillary data (specifically time to pressure and altitude correspondence). Processing ========== In the engineering data, corrections were applied to thermistor sensor data. This correction was the product of analysis of discrepancies between Ambient Wall temperatures and Probe Atmospheric Structure Instrument Experiment temperatures. Details can be found in [SROMOVSKYETAL1998]. Fluxes computed from counts included corrections for detector temperature dependence, thermal perturbations, and correlated noise. Details can be found in [SROMOVSKYETAL1998]. Data ==== A concise description of each file in the archive follows, segregated by subdirectory. nfr/calib: nfrfovX.lbl -- header labels for field-of-view data for channel X, where X is channel name, A-F nfrfovX.dat -- data files for field-of-view data for channel X tdepresp.tab -- temperature dependent absolute responsivity data tdsrX.tab -- temperature dependent spectral response for channel X nfr/edr: nfr0528x.sdm -- final merged Experimental Data Record (EDR) file nfr/engnring: nfra1.tab -- ambient wall temperature, high range nfra1vv.tab -- ambient wall temp., high range, corrected drive voltage nfra2.tab -- ambient wall temp., low range nfra2vv.tab -- ambient wall temp., low range, corrected drive voltage nfrbi.tab -- hot blackbody heater current nfrdt.tab -- detector temp. nfret.tab -- electronics module temp. nfrhb.tab -- hot blackbody temp. nfrhbvv.tab -- hot blackbody temp., corrected drive voltage nfrv1.tab -- A/D converter reference voltage (+10V, V1) nfrv2.tab -- preamp module voltage (+7V, V2) nfrwi.tab -- diamond window heater current nfrwt.tab -- diamond window temp. nfrwtvv.tab -- diamond window temp., corrected drive voltage nfr/fluxes: mctcnf.tab -- m-corrected, temperature-corrected net fluxes mctcnfdn.tab -- m-corr., temp-corr. net fluxes, correlated noise removed mctcuf.tab -- m-corr., temp-corr up fluxes rawnf.tab -- uncorrected net fluxes rawnfdn.tab -- uncorrected net fluxes, correlated noise removed rawuf.tab -- uncorrected up fluxes tcnf.tab -- temp-corrected net fluxes tcnfdn.tab -- temp-corrected net fluxes, correlated noise removed tcuf.tab -- temp-corrected up fluxes nfr/fluxes/calib: bbamb.tab -- computed flux from ambient wall blackbody bbhot.tab -- computed flux from hot blackbody bcflux.tab -- computed Blackbody Cal mode flux (bbhot - bbamb) nfr/raw: nfraz.tab -- Analog Zero (AZ) mode counts, short-cycled nfrbc.tab -- Blackbody Cal (BC) mode counts nfrerr.tab -- position error bit counts nfrgsa.tab -- Gain Select Amplitude (GSA) counts nfrnf.tab -- Net Flux (NF) mode counts, non-short-cycled data nfrrXX.tab -- raw counts for engineering data in nfr/engnring nfrsc.tab -- Net Flux (NF) mode counts, short-cycled data nfruf.tab -- Up Flux (UF) mode counts nfr/raw/denoised: nfrnfdn.tab -- NF mode counts, non-short-cycled, correlated noise removed nfrscdn.tab -- NF mode counts, short-cycled, correlated noise removed nfr/catalog: nfrinst.cat -- instrument description file referenc.cat -- document reference file dataset.cat -- this file software: nfredr41.c -- C program for reading EDR file nfredr4.h -- include file for nfredr41.c read_flux.pro -- example IDL program for reading flux file and interpolating pressure from ASI data readfile.pro -- IDL file reading function called by read_flux.pro Data Reduction Example ====================== The following example is to aid in applying the slowly varying offset correction to the temperature-corrected, correlated-noise-removed net fluxes in /data/nfr/fluxes/tcnfdn.tab. Slowly Varying Offset Correction Equation 15 in [SROMOVSKYETAL1998]. F_nc = F_nr - m_n*C_F*(G_n/G_F)*(R_F_Tr/(R_F_T*R_n_Tr)) Where: F_nc Net flux in channel n [A,B,C,D,E,F] m-corrected, temp-corrected net fluxes, correlated-noise-removed. (W/m^2) Corrected fluxes in /data/nfr/fluxes/mctcnfdn.tab F_nr Net flux in channel n [A,B,C,D,E,F] temperature-corrected net fluxes, correlated-noise-removed. (W/m^2) Fluxes in /data/nfr/fluxes/tcnfdn.tab m_n Multiplier factor, m-factor. Adapted values for channels [A,B,C,D,E,F], uncertainties are (xx) [SROMOVSKYETAL1998] Table 2): [1.05 (0.15),0.70 (0.1),3.90 (0.2),2.10 (0.05),1.35 (0.05),1.00] C_F Channel F temperature-corrected net flux counts, correlated-noiseremoved. Counts in /data/nfr/raw/denoised/nfrnfdn.tab or nfrscdn.tab NOTE: These counts should be smoothed. [SROMOVSKYETAL1998] used a sliding quadratic fit over 19 successive points. G_n,G_F Gain for channel n and F respectively. G_n = [127,218,408,321,403,127] ([SROMOVSKYETAL1998] Table 2) G_F = 127 R_F_Tr Responsivity of channel F at the reference temperature of 25 degrees C. R_F_Tr = [255.7,771.9,1399.6,953.0,1364.9,255.7] Responsivity in /data/nfr/calib/tdepresp.tab. R_F_T Responsivity of channel F at the respective detector temperature of TD_temp. Responsivity in /data/nfr/calib/tdepresp.tab. Detector temperature in /data/nfr/engnring/nfrdt.tab R_n_Tr Responsivity of channel n at the reference temperature of 25 degrees C. Responsivity in /data/nfr/calib/tdepresp.tab. For the pressure nearest the 5 bar level, time = 1161.75, Major frame = 9, minor frame = 12, time = 1158.75, TD_temp = -17.79 F_nr = [3.573,0.029,5.191,2.380,1.037,1.331] m_n = [1.05,0.70,3.90,2.10,1.35,1.00] C_F = 324.3 (uncorrected = 318, average of 5 = 320.78) G_n = [127,218,408,321,403,127] R_n_Tr = [255.7,771.9,1399.6,953.0,1364.9,255.7] R_F_t = 239.0 Inserting the values above into Equation 15 of [SROMOVSKYETAL1998] F_nc = F_nr - m_n*C_F*(G_n/G_F)*(R_F_Tr(5)/(R_F_T*R_n_Tr)) Gives the corrected flux values: 2.148 -0.511 2.085 0.448 -0.052 -0.026 Corresponding values from /data/nfr/fluxes/mctcnfdn.tab: 2.148 -0.511 2.084 0.447 -0.056 0.000 Ancillary Data ============== This includes data from the ASI team which contains correspondence between time, altitude, and pressure. This file is based on ASI data received 28 May 1997; please retrieve the most recent data from the ASI experiment archive. Coordinate System ================= The NFR data files include time (specifically time after Minor Frame Zero), which can be used to compare results to those of other Probe instruments, and to associate altitude and pressure information to the NFR data points (using the ancillary information described above). Software ======== Software include in the data set includes: nfredr41.c: Software for decoding the NFR EDR file and writing files of instrument counts.

Data Set Overview

This Galileo Probe Mass Spectrometer (GPMS) data set includes: 1. Jupiter atmospheric entry data from December 7, 1995. 2. Instrument characterization data; March - April, 1985. 3. Residual background data from Earth testing; 1985 - 1989. 4. Residual background data from space; 1989, 1990, 1992. 5. Characterization data from the refurbished Engineering Unit. NOT YET AVAILABLE - December, 1998 6. Sequence and conversion tables necessary to process the data. This data set contains the Mass Spectrometer instrument data from the Galileo Probe mission that entered the atmosphere of Jupiter on December 7, 1995. The GPMS instrument operated for approximately 58 minutes (7000 steps). Approximately 50 minutes of the data are of high quality. Also included are data files necessary to characterize the operation and behavior of this instrument and data files needed to demonstrate the integrity of the GPMS instrument over the lengthy duration of the mission. Additionally, the Engineering Unit was refurbished to flight quality and has yielded data that help understand the results from the mission and these data are included with this data set. The data tables and conversion files required to process the raw data are also included. Documentation reviewing the steps necessary to go from telemetry to more useful (meaningful) data formats are included. Finally, in the entry data set Probe time and Probe descent pressure data are included. The pressure data are from the Atmosphere Structure Instrument. These last two data items will not be detailed further in this work. In 'real' time (i.e., on December 7, 1995) the data were telemetered from the Galileo Probe to the Galileo Orbiter. These data were redundantly stored both in 'excess' orbiter memory and on a tape recorder. The initial data sent to Earth, beginning on December 10, 1995, were those stored in the Orbiter's memory. Following this, the data stored on the tape recorder were sent to Earth. Between December 1995 and July 1996, 37 files containing mission data were delivered to us. Some of these files contained unprocessed telemetry data (i.e., as it was received.) Other files contained data that had been checked and 'bested'. (Bested indicates data where error corrections have been applied.) In most instances each 'new' data file contained the existing data plus some new data. Effectively the data were 'redundantly' telemetered to the Earth *2?* times. The most useful (complete) data files are tagged with dates of February 5, April 16, and July 1, 1996. The reasons for this method of data return include: 1. The failure of the Orbiter high gain antenna. 2. The problems with the Orbiter's (sticking) tape recorder. 3. Time use allocations with the Deep Space Antenna Network. 4. The fact that Jupiter and Earth were located on opposite sides of the Sun in early 1996 resulting in a poor signal to noise ratio. The Galileo Probe Mass Spectrometer instrument steps through a pre-programmed sampling sequence. Each measurement results in a count rate related to the mass programmed for that step. The nominal integration period for each step was 0.5 second. The data also yield a data bit indicating a detector sensitivity mode (LOW or HIGH) for that measurement. (At large count rates the instrument automatically switches to a LOW sensitivity mode so as to not overload and damage the detector.) Also returned with each measurement are two data bits of instrument 'housekeeping' information. Each GPMS Instrument minor frame (8 steps) yields two (2) housekeeping parameter values. - - - - - - - - - A short mass spectrometer informational interlude. The GPMS instrument is also referred to as a Neutral Mass Spectrometer (NMS). Such an instrument is composed of an inlet system, an ionizer, ion optics (lenses), a mass filter and a detector. All of this is inside of a high-vacuum chamber. The function of the inlet system is to channel your sample to the mass spectrometer (ms). Because the ms requires a good vacuum, you must allow only a fraction of the incoming sample into the vacuum system. Calibrated leaks are used for this purpose. The mass filter allows only those ions with the proper mass to charge ratio (generally referred to as mass or Daltons or AMU) to pass. A mass filter 'works' because in the presence of electromagnetic fields in a vacuum, the trajectories of ions are predictable. The ionizer is often a heated filament designed to emit electrons with a defined energy (voltage). These electrons collide with gases entering the ionizer and a small fraction of the species acquire a charge. The larger the ionization energy, the more violent the effects. When all is working nicely, the ion acquires a unit charge. When the species is a molecule, it will usually break up into fragments; the exact fragmentation pattern is determined by bond energies and the ionization energy. Ion lenses are useful for directing the ions toward a specific target. A good detector of ions is an electron multiplier. The GPMS Instrument: 1. Two inlets with larger leaks used on Inlet 1 than on Inlet 2. (Because the pressure is lower up high where Inlet 1 is used.) Micron sized (7 channel) capillary leaks are used. 2. Vacuum maintained by the use of ion and chemical getter pumps. 3. Quadrupole Mass Filter 4. Electron bombardment ionizer with 3 ionization energy options. 5. Several lenses are used to 'steer' the ions. 6. Electron multiplier is used as the detector. - - - - - - - - - In order to translate the housekeeping data returned by the GPMS instrument, a table of conversion coefficients is required. The application of these conversion coefficients yields parameters in meaningful units (Volts, Amperes) instead of 'telemetry mystery units'. Also needed is a table indicating the GPMS parameters (mass, ionizer energy) associated with each step of the sampling sequence. These tables are parts of this data set. Contained in the instrument's housekeeping parameters are a GPMS SYNC PATTERN. These parameters are necessary to 'lock' the programmed sequence with the returned data. Most of the GPMS data are in the form of standard mass sweeps. During these sequences the mass is incremented in integral (1) Atomic Mass Unit (amu) steps between sample integrations. Typically the sweep steps over a mass range from 2 to 150 amu with the ionizer set to operate at 75 volts. The circuitry associated with the electron multiplier (detector) normally starts its measurement in the HIGH sensitivity mode. When the count rate exceeds a defined threshold, (excessive signal yielding too much current in the multiplier) the system switches the detector to the LOW sensitivity mode. Occasionally measurements are made where the GPMS instrument is incrementing in 0.125 amu steps, is operating using ionization energies of 25 or 15 Volts, is set to measure specific mass values at chosen ionization energies, has been forced to use the LOW sensitivity detection mode of operation and such. The overall GPMS sequence includes the following subsequences: 1. Instrument Background: Selected residual gases (masses) in the instrument are monitored as soon as power is applied and until Inlet 1 and Outlet 1 are opened to the atmosphere. 2. Photochemical Region: The molecules most likely to exist in the upper atmosphere probably evolved as a result of photochemical processes. Masses corresponding to the anticipated molecules are monitored. Selected masses are monitored at least once every 30 seconds. The collection of a sample by Enrichment Cell 1 was initiated. The enrichment cells work by pulling a large volume of sample across a sorbent material ('Carbosieve'). The hydrogen that dominates the Jovian atmosphere is pumped away using chemical getter pumps. 3. Below the Ammonia Clouds: It was believed that the uppermost clouds visible on Jupiter were composed of Ammonia and possibly including Hydrogen Sulfide. In this region a slightly modified sampling scheme was used. The inlet to the Enrichment Cell was closed and processing of this sample started. 4. Instrument Background: At this phase of the mission, the atmospheric entry models predicted the presence of a water cloud. To avoid problems that can arise if a drop of water entered the inlet of the mass spectrometer, it was decided to terminate direct atmospheric measurements and prepare the GPMS instrument for important special sequences. At this time, in the sequence, valves were closed to isolate the mass spectrometer from the Jovian atmosphere and instrument background measurements were obtained. 5. Rare Gas Measurements: Following the charging of Enrichment Cell 1, a valve was opened to allow those gases not sorbed by the enrichment cell material to (volume expand) enter the Rare Gas Cell. An additional getter pump helps remove any remaining hydrogen from the gas mixture. The gases remaining were expected to be primarily the Rare (Noble) gases. Following the completion of the instrument background measurements, valves were opened to allow these gases into the mass spectrometer for analysis. 6. Enrichment Cell 1 Measurements: The processing of the gases in the enrichment cell consists of heating the cell to drive off those volatile materials sorbed on the 'Carbosieve' material. These gases were added to those already in the Rare Gas Cell and analyzed by the mass spectrometer. 7. Instrument Background: Following the evaluation of the contents from the special cells, additional instrument background scans were done. 8. Inlet 2: Inlet and Outlet 2 were opened to monitor samples directly from the deeper Jovian atmosphere. Most of the sequences done in this region consist of full mass scans because it was expected that more complicated molecules would exist at these higher pressures. In a similar fashion to that previously noted, Enrichment Cell 2 was charged with sample. 9. Enrichment Cell 2: Following sample processing, the contents from the second enrichment cell were analyzed by the mass spectrometer. These samples were superposed on the sample entering from the direct atmosphere. 10. High Resolution Scans: A single 0.125 amu per step mass scan was multiplexed into the sequence. Parameters ========== The GPMS measurements yield a count rate for the sampling integration time; here nominally 0.5 second. The resulting count rate as a function of mass is a measure of qualitative and quantitative information about the atomic and molecular species entering the instrument. The actual integration period for each step is 0.48375 seconds. The observed count rate must also be corrected for the limitations of the detector circuitry. One well documented problem at higher count rates is pulse pile up where the events occurring at the detector are happening faster than the circuitry can recover. Data corrected for this effect are part of the data set. Data - Atmospheric Entry ======================== The operation of the GPMS instrument was expected to begin at an ambient pressure of 0.1 Bars. As the result of a probe problem, the actual start of the instrument's sequence began at a pressure of ca. 0.5 Bars. The data included in the file, GPMSDATA.DAT, include Column 1: Sequence Step Column 2: Probe Time (Seconds after Major Frame/Minor Frame 0/0.) Column 3: Ambient Pressure (millibars) (from ASI measurements) Column 4: Ionization (electron) Energy (electron Volts) Column 5: Mass being sampled (amu) Column 6: Detector Sensitivity (HI or LO) Column 7: Uncorrected Count Data (counts per period) Column 8: Corrected Count Data (counts per period) Column 9: (Where present) Inlet System Operation Steps The initial telemetry data forwarded by the project, in the form of System Data Manager (*.SDM) files, contained errors. (Note: *.SDM files are not included in the PDS data set.) The GPMS data were redundantly sent on both the 'A' and 'B' telemetry data systems. The Probe data were also stored both in the (excess) Orbiter's memory and on the Orbiter's tape recorder. The data from each of these were independently telemetered to the Deep Space Network antennas on Earth. As new batches of data were received on Earth and the Jupiter-SunEarth geometry improved, the quality of the telemetry data plus the error correction and besting procedures yielded a high quality raw data product. Eventually we identified and rejected only 2 readings from the final 7000+ values as being in error. The data files (*.SDM files) consist of data records sized at 100 (8-bit) words. (The first data word is indexed (numbered) as zero.) These records are recorded as BINARY data (often referred to as a DIRECT ACCESS format.) The first 36 of these data words contain data system identification plus counter and time information. The remaining 64 (8-bit) words contain the telemetry for 1 minor frame of Galileo Probe data. All data not related to the GPMS instrument were 'zeroed' by the Galileo Probe Project office before we received a file. Extracting the Probe telemetry yields Probe data records. The GPMS data occupy positions numbered 6, 7, 14, 15, 22, 23, 30, 31, 38, 39, 46, 47, 54, 55, 62 and 63. Two of the data records, from the data file nms0701a.sdm (July 1, 1996), are shown next. These data records are tagged with the mission date 12/07/95 and the time tag shown. Word 0 indicates the data system used (A or B). Words 36, 37 and 38 (Probe words 0, 1 and 2) show the Probe SYNC pattern. Word 40 (Probe word 4) is a counter. ------------------------------------- Comments 6 0 92 0 1 0 64 0 0 Header (36 entries) 0 0 0 7 252 46 22 171 49 Data Stream >B< 7 252 46 22 171 33 7 252 46 22:46:08.247 22 171 33 134 5 48 22 82 227 248 197 73 0 66 100 0 39 Probe Data (64 Entries) 0 0 0 0 0 0 1 252 125 7 0 0 0 167 0 32 0 0 0 0 0 0 192 41 Multana = 3 168 125 93 156 0 0 64 26 0 0 0 0 0 0 0 29 81 228 205 83 0 123 0 25 0 0 0 0 0 0 192 24 Housekeeping = 67 ------------------------------------- Comments 5 0 92 0 1 0 64 0 0 Header (36 entries) 0 0 0 7 252 46 22 93 36 Data Stream >A< 7 252 46 22 93 36 7 252 46 22:48:09.093 22 93 36 134 5 48 22 116 228 248 197 73 0 65 73 0 31 Probe Data (64 Entries) 0 0 0 0 0 0 1 252 0 7 0 0 0 245 0 32 0 0 0 0 0 0 192 41 Multana = 3 14 125 93 156 122 0 64 26 0 0 0 0 0 0 0 29 0 228 206 83 204 7 0 25 0 0 0 0 0 0 192 24 Housekeeping = 67 Fortunately the Probe and GPMS minor frames are synchronized. Each Probe minor frame yields one minor frame of GPMS data. This GPMS minor frame of data yields 8 count rates and associated detector sensitivities plus two housekeeping parameters. These data are extracted from the data as indicated next. | HIGH (Even No. Word) | LOW (Odd No. Word) | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | 7| 6| 5| 4| 3| 2| 1| 0| 7| 6| 5| 4| 3| 2| 1| 0| 8-bit +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |<-HK>| S|<Exponent->|<--------Mantissa-------->| +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |15|14|13|12|11|10| 9| 8| 7| 6| 5| 4| 3| 2| 1| 0| 16-bit +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ msb lsb where: msb = most significant bit lsb = least significant bit HK = GPMS Housekeeping bits (0 - 3) S = GPMS Sensitivity Bit (0 = HI, 1 = LO) Exponent = Count Exponent (0 - 7) Mantissa = Count mantissa (0 - 511) Note: The GPMS data are log compressed. The success of this method requires that the counter always starts at 1. The combination: Mantissa = Exponent = 0 can NEVER occur! To determine the uncorrected count data, the following rules apply: If Exponent = 0 COUNT = Mantissa - 1 If Exponent > 0 COUNT = (512 + Mantissa) * 2 ^ (Exponent - 1) + 2 ^ (Exponent - 2) As long as the count is less than, approximately, 1. E+7, the CORRECTED count rate is derived from the following relationship: OBSERVED = TRUE * exp(-TRUE / z) where: OBSERVED = Raw (Observed, Uncorrected) Count data TRUE = Actual (Real, Corrected) Count data z = Constant value determined for this specific instrument z = 2.933 E+7 The housekeeping parameter values are derived as follows: MULTANA = 64 * W(6) + 16 * W(14) + 4 * W(22) + W(30) HK = 64 * W(38) + 16 * W(46) + 4 * W(54) + W(62) where: MULTANA = Multiplier Analog Current: A measure of the current from the electron multiplier. HK = One of 32 repeating GPMS 'health' parameters. W(6)...W(62) = The value from the two data bits into which these housekeeping parameters are coded. Data - GPMS Instrument Characterization ======================================= THESE DATA ARE NOT CONSIDERED TO BE QUANTITATIVE! The GPMS instrument's capabilities were tested in March and April of 1985 in the laboratory at GSFC. These tests were performed using selected pure gases and gas mixtures to demonstrate that the instrument could detect these species. These tests were NOT meant to be quantitative! During these tests the leaks used with the enrichment cells were several hundred to a thousand times smaller than those used during the actual Jovian atmospheric entry. (This was done to prevent damage to the fragile components in the mass spectrometer's ionization source that would occur in the event of an air leak or a pressure surge.) The characterization gas handling system shown in the diagram NMSCLBR.GIF was used. This system is a recirculating system where the pressures and temperatures of the gas sample can be controlled. The data file names indicate the GPMS instrument inlet (I1 indicates Inlet 1 and I2 indicates Inlet 2) by which the gas sample was introduced as well as the identity of the gas sample. The data files include the following: File Name Inlet Gas Sample i1_h2s 1 Hydrogen Sulfide i1_hcn 1 Hydrogen Cyanide i1_hydr 1 Mixture of inorganic Hydrides i1_ph3 1 Phosphine i1_rg 1 Rare Gas Mixture i1_rgp 1 Rare Gas Mixture at selected pressures i2_alkan 2 Mixture of saturated alkanes i2_chmx 2 Mixture of saturated and unsaturated hydrocarbons i2_h2nh3 2 Ammonia plus hydrogen mixture i2_h2o 2 Water sample i2_h2s 2 Hydrogen Sulfide i2_hcn 2 Hydrogen Cyanide i2_hydr 2 Mixture of inorganic Hydrides i2_nh3 2 Ammonia i2_ph3 2 Phosphine i2_rg 2 Mixture of Rare Gases i2_unsat 2 Mixture of Unsaturated Hydrocarbons pfusim 1 & 2 90% hydrogen 10% helium mixture introduced using a pressure profile simulating the expected entry. Data - Waiting for Launch ========================= NMS85183, NMS88201 A89MY15, A89MY15A, A89JL19, A89SE14, A89SE14A B89MY15, B89MY15A, B89JL19, B89SE14, B89SE14A These data are an important monitors of the 'history' and handling of the instrument. The data in these files indicates the cleanness of the instrument and that it remained (vacuum) leak free. (Note: files A89MY15A, B89MY15A and B89SE14A contain no data, and are not included in this archive.) The data files are included for both the 'A' and the 'B' data streams and include: July 2, 1985 instrument test at GSFC. This test was done immediately after the 'final' processing and sealing of the GPMS vacuum system. July 19, 1988 test at GSFC. This is the last test with the instrument prior to its final delivery for processing and launch. The GPMS was allowed to perform a full sampling sequence with the enrichment cell heaters operational during this test. May 15, 1989 ground MST testing at KSC (This Mission Sequence Test is intended to simulate the timeline and events expected at entry.) July 19, 1989 'ground' Probe Baseline testing at KSC. September 14, 1989 'onboard shuttle' Probe Baseline testing at KSC. Data - Cruising in Space ======================== A89OC26, A89OC27, A90DE04, A90DE04A, A92NO20, A92NO21 B89OC26, B89OC27, B90DE04, B90DE04A, B92NO20, B92NO21 The GPMS instrument was tested three times following its launch from the space shuttle. The data from both the 'A' and 'B' data streams is included with this data set. (Note: files B89OC27 and B90DE04 contain no data, and are not included in this archive.) The data files include: October 26, 1989 first turn on data from space December 4, 1990 Probe Baseline test (SFT) from space November 20, 1992 MST (full sequence) test from space Data - Entry ======================== A95DE07 B95DE07 Also included are the 'A' and 'B' string data from the entry on December 7, 1995. These data files are formatted identically to the files noted (above) that present the ground and space GPMS instrument testing results. The instrument's housekeeping data is also included in these data files. Data - Refurbished Engineering Unit =================================== *** NOT YET AVAILABLE at the beginning of 1999. *** The Galileo Probe Engineering Unit was refurbished to 'Flight Quality' following launch. This instrument is in the laboratory at GSFC and is being used in attempts to simulate the observations from the mission. *** NOT YET AVAILABLE at the beginning of 1999. *** Data - Miscellaneous ==================== NMSCOEFF, NMSSTEPS The file NMSCOEFF.TAB contains the coefficients necessary to convert the GPMS raw housekeeping data into real world Engineering units. The file NMSSTEPS.TAB contains all of the details that have been programmed into the GPMS instrument's sampling sequence such as the mass, electron energy, and sensitivity conditions used for each step. This file also documents the instrument's inlet system operations and other parameters as programmed. Software ======== The (IBM PC/Clone) executable program NMSSEQ.EXE is a self-extracting program that creates a set of files that display a cartoon of the GPMS instrument's operation. This file will create 3 files in the subdirectory from which it is run.

These data are available on-line from the Planetary Data System (PDS) at: http://pds-atmospheres.nmsu.edu/PDS/data/gp_0001/

Alternate Names

  • Galileo Probe Rawa Data from PDS
  • GP-J-ASI-3-ENTRY-V1.0
  • GP-J-DWE-3-ENTRY-V1.0
  • GP-J-EPI-3-ENTRY-V1.0
  • GP-J-HAD-3-ENTRY-V1.0
  • GP-J-LRD-3-ENTRY-V1.0
  • GP-J-NEP-3-ENTRY-V1.0
  • GP-J-NFR-3-ENTRY-V1.0
  • GP-J-NMS-3-ENTRY-V1.0
  • Galileo Probe ASI Raw Data Set
  • Galileo Probe Doppler Wind Experiment Data V1.0
  • Galileo Probe EPI Raw Data Set
  • Galileo Probe Helium Abundance Detector Data V1.0
  • Galileo Probe LRD Raw Data Set
  • Galileo Probe NEP Raw Data Set
  • Galileo Probe NMS Raw Data Set
  • Galileo Probe Net Flux Radiometer Data V1.0

Discipline

  • Planetary Science: Atmospheres

Additional Information

Spacecraft

Experiments

Questions and comments about this data collection can be directed to: Dr. Edwin V. Bell, II

 

Personnel

NameRoleOriginal AffiliationE-mail
Dr. Harald M. FischerData ProviderUniversitat Kielhfischer@physik.uni-kiel.de
Dr. Louis J. LanzerottiGeneral ContactNew Jersey Institute of Technologylouis.j.lanzerotti@njit.edu
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