Data Set Overview : This data set contains raw radio tracking data from the Ulysses (ULY) Solar Corona Experiment (SCE) obtained during the ULY Jupiter flyby. The data target the Io Plasma Torus (IPT) and cover the period 1992-02-04 20:28 to 1992-02-09 15:44. The data set includes 10 NASA Deep Space Network (DSN) Archival Tracking Data Files (ATDF or TDF), and documentation. The data are obtained from the Radio Science Support group at JPL. There are basically two types of data: ranging and Doppler (Frequency), recorded as a function of UT Ground Received Time. These ranging and Doppler data are obtained from the standard DSN tracking receivers. Doppler data are often used to infer spacecraft radial motion relative to the tracking antenna. The radio downlinks from Ulysses were monitored during the passage of the spacecraft through the IPT shortly after closest approach to Jupiter. The electron content of the Io torus was derived from the dispersive phase shift of the S-band (2.3 GHz) signal with respect to the X-band (8.4 GHz) signal. Corrections were applied for non-Jovian contributions to the change in electron content arising from the interplanetary medium and the terrestrial ionosphere. Ulysses' North-to-South encounter trajectory was well suited for investigating the global structure of the Jovian plasma environment near Io's orbit, especially its latitudinal extent and azimuthal variations. (IPT investigation description adapted from [BIRDETAL1993]. For more information please refer to the complete paper.) Parameters : Each ATDF data record contains 117 parameters, stored in records of 288 bytes. A physical record (8064 bytes) consists of 28 logical records. Among these parameters are signal levels ('AGC' : automatic gain control in dBm), antenna pointing angles, frequency (often referred to simply as 'Doppler'), range, and residuals. Data values are reported at rates no higher than 10 per second. For the Ulysses Jupiter encounter the received frequencies at S-Band and X-band were recorded at a sample time of one per second. The ATDF is described in section TRK-2-25 of the JPL Document 820-13 [TRK-2-25]. An ASCII copy of this document (TRK_2_25.TXT) is included in the DOCUMENT/SCE directory of this volume. Processing : ATDFs are files of radiometric data produced by the Network Operations Control Center (NOCC) Navigation Subsystem (NAV). They are derived from Intermediate Data Records by NAV and contain all radiometric measurements received from the DSN station. Data : ATDFs contain precise radio range and Doppler measurements made between DSN ground stations and a spacecraft. During the Ulysses Jupiter encounter, coded waveforms were transmitted from the Earth, relayed by the on-board Ulysses telecommunications system, and received back on Earth. Cross correlation between the transmitted and received waveforms yielded a measurement of the round trip distance, which could then be related to the Earth-Venus distance during the flyby. Doppler shift from the same measurements could be interpreted as relative velocity along the propagation path. An ATDF has a file name of the form 'ydddeeeX.TDF' where 'y' is the least significant digit of the year and 'ddd' is the day-of-year for the first ATDF record. The 'eee' gives day-of-year for the last data record in the ATDF. 'X' indicates file sequence when there are multiple files per start/stop day-of-year ('A' for the first file, 'B' for the second, etc.). Each ATDF is accompanied by a full PDS detached label with name ydddeeeX.LBL which completely describes the contents of the ATDF. The format and contents are also described in TRK_2_25.TXT in the DOCUMENT/SCE directory this volume. Both the ATDF and its label are stored in the TDF directory of an archival volume. Ancillary Data : Observing Geometry ------------------ A NAIF (PDS Navigation and Ancillary Information) 'transfer' format SPK file is provided for the period 1992-01-05 to 1995-10-31. This file contains the positions of Ulysses, Jupiter Earth, the Sun, and Jupiter's four Galilean satellites (Io, Europa, Ganymede, and Callisto) in data modules that can be read with software from the NAIF Toolkit. This 'transfer' format SPK file (ULY92106.XSP) is located in the GEOMETRY directory. It is accompanied by a detached PDS label (ULY92106.LBL) which describes some of the SPK file's characteristics. Before using 'transfer' NAIF files, the user should convert the ASCII carriage-return line-feed delimiters on each record to the default delimiter for text files on the local system, then use the NAIF utility SPACIT to convert the archival file to local binary. An overview of the SPICE data system can be found in SPICE.TXT located in the DOCUMENT directory of this volume. For additional information on acquiring, installing, and using SPICE data or software please contact the PDS NAIF node: Address: Jet Propulsion Laboratory Mail Stop 301-125L Pasadena, California 91109-8099 Phone: (818) 354-3869 E-mail: Charles.Acton@jpl.nasa.gov or pds_operator@naif.jpl.nasa.gov Documentation ------------- Included in the DOCUMENT directory is an ASCII version (TRK_2_25.TXT) a document [TRK-2-25] describing the format of the ATDF data files contained on this volume. Coordinate System : Most data types are not dependent on definition of a coordinate system; for those that are, the user should consult the SIS for information. Software : Software for parsing, reducing, and analyzing these data has been developed at the University of Bonn (Germany), the Jet Propulsion Laboratory, and other institutions. Because parsing must be done at the bit level, adaptation of the software to other platforms is not always easy. No software has been prepared for general distribution, and none is included with this archive. Users should refer to the PDS labels and Software Interface Specifications (/DOCUMENT/TRK_2_25.TXT) for detailed information on file formats before writing their own software. Media/Format : This archival data set is written on DVD-R media on a Pioneer DVR-A03 recorder (a DVD-R for General, 650 nm wavelength). The DVD-R volume conforms to ISO 9660 standards.

Overview : There are no known limitations to use of these data, subject to signal-to-noise considerations which would be typical for systems of this type. Review : Prior to creation of the final version of the archival data set, the archive was distributed to both PDS and non-PDS personnel, including the PDS Radio Science advisor, for preliminary review. Data Coverage and Quality : The data cover the Jupiter encounter period from 1992-02-04 to 1992-02-09. Data coverage is as follows: File bytes start time stop time ------------ -------- ---------------- ---------------- 2035036A.TDF 31522176 1992-02-04 20:28 1992-02-05 17:00 2036037A.TDF 30119040 1992-02-05 15:45 1992-02-06 05:05 2037037A.TDF 30119040 1992-02-06 03:35 1992-02-06 14:08 2037038A.TDF 33755904 1992-02-06 12:53 1992-02-07 03:44 2038038A.TDF 32578560 1992-02-07 02:30 1992-02-07 16:15 2038039A.TDF 30989952 1992-02-07 15:00 1992-02-08 04:30 2039039A.TDF 26038656 1992-02-08 03:15 1992-02-08 12:00 2039040A.TDF 33763968 1992-02-08 11:45 1992-02-09 00:00 2039040B.TDF 33626880 1992-02-08 22:45 1992-02-09 10:15 2040040A.TDF 32812416 1992-02-09 09:00 1992-02-09 15:44 In addition to the normal signal-to-noise constraints, the following known data quality issues apply to this data set: S-band coverage commences at 1992-02-05 19:44 (DOY 36) and terminates 1992-02-09 19:16 (DOY 40). Limitations : None.