Aerospace Agency Tapes The Aerospace Agency Tapes contain subsets of the data collected by the CRRES satellite [1] from 25 July 1990 to 11 October 1991. The subset is the data processed by a set of three data processing units (DPUs) provided by The Aerospace Corporation, which also provided most of the instruments for a set of 8 experiments. Each of the instruments interfaced with one of the three DPUs, DPUA [2,5], DPUB [3,5], and DPU57 [4,5]. DPUA controlled the AFGL-701-11A instrument, the Magnetospheric Ion Composit- ion Spectrometer (MICS) provided by the Max Planck Institut fur Aeronomie, Lindau, Germany. A complete description of the MICS is given in [2,6]. DPUB controlled AFGL-701-11A which consisted of two instruments, the Heavy Ion Telescope (HIT) [3,7] and the Low Energy Magnetospheric Ion Composition Sensor (LOMICS) [3,8], both provided by the Los Alamos Scientific Laboratory. DPU57 controlled AFGL701-5A, the Medium Electrons A spectrometer (MEA) [4,9], -5B, the Electron and Proton Wide-Angle Spectrometer (EPAS) [4,10], -7A, the Relativistic Proton Detector (RP) [4], and a 4-band photometer used during chemical releases [4], and -7B1 and -7B2, the Proton Swithches (PS1 and PS2, which were omnidirectional proton sensors) [4,11]. The CRRES Aerospace Agency Tapes [12,13,14] on these disks are organized as follows: data from each orbit of the CRRES satellite during which the Aerospace complement of experiments was active are presented as a set of 5 files, A HEADER file, an EPHEMERIS file, an ATTITUDE file, a MAGNETIC FIELD file, and the instrument raw data file. The instruments were turned on during Orbit 6, turned off at Orbit 365, and back on during Orbit 416. The instruments remained on for the remainder of the mission (which terminated with a battery failure on Orbit 1067). Operations were such that the LASSII complement of instruments [15] were given 20-minute or 1-hour periods at low altitude on a regular schedule. When the LASSII instruments had access to telemetry, the RADSAT complement [16] which included the Aerospace Corporation instruments was off. This resulted in frequent small gaps in the data. Occasionally, telemetry tapes were not processed (due to loss or unreadablity of the analog tapes), resulting in a partial orbit. Each orbit is represented by 5 files: CRnnnn.HED Header file identifying the orbit, date, etc., 120 bytes CRnnnn.EPH Ephemeris file, blocked in 240-byte records CRnnnn.ATT Attitude coefficients file, blocked in 80-byte records CRnnnn.FPM Magnetic field file, blocked in 32000-byte records CRnnnn.DAT Aerospace raw data, blocked in 8160-byte records where nnnn is the orbit number. HEADER FILES: Descriptions of the header files are given in [12,13,14]. The format is provided in file HEDFORMT.TXT in the subdirectory DOCUMENT on CD-35. A PC program, HEADER, is provided on CD-35 which reads the CRnnnn.HED files and dumps them to screen. When using HEADER, the header file to be dumped must be provided as an argument in the call. The FORTRAN source code is provided for those who wish to run the program on another platform. This source code may be examined to obtain precise detail about the format of the .HED files. CD-35 includes a file, HED.ZIP, which is a ZIPped compilation of all of the header files from the 35-CD set. To extract a header file, PKUNZIP.EXE must be used. It is provided on CD-35. This is a distributable version of the PKWARE PC unpacking program. The call is: PKUNZIP HED.ZIP CRxxxx.HED where xxxx can be any discriptor, including wild cards. NOTE: The order of bytes in a 32-bit integer is different on different platforms (header file data items are coded as 32-bit positive integers with offsets). The software provided on CD-35 is appropriate for use on a PC, but if it is to be used on another platform, byte order may have to be changed. EPHEMERIS FILES Descriptions of the EPHEMERIS files are given in [12,13,14]. The format is provided in file EPHFORMT.TXT in the subdirectory FORMAT on CD-35. An interactive PC program, EPHEMER, which reads the CRnnnn.EPH files and dumps them to screen or a file, is provided on CD-35. It is called without an argument and asks for the file name. If the corresponding CRnnnn.HED file is in the same directory with the CRnnnn.EPH file, it will automatically provide a dump of the .HED file. The listing of the file includes UT, altitude, latitude, longitude, B, L, and B0. The FORTRAN source code is provided for those who wish to run the program on another platform. As with the header files, a ZIPped file containing all of the ephemeris files is available on CD-35. Again, be aware that a PC stores bytes in a different order from that of other platforms. ATTITUDE FILES Descriptions of the ATTITUDE files are given in [12,14]. The format is provided in file ATTFORMT.TXT in the subdirectory FORMAT on CD-35. The source code for the program, AGMOD.FOR, which reads the CRnnnn.ATT files and processes them, is provided in the same subdirectory. This FORTRAN source code is provided for those who wish to determine attitude for the CRRES satellite. As with the header files, a ZIPped file containing all of the attitude files is available on CD-35. A manual for using AGMOD is provided in the file AGMOD.TXT in the FORMAT subdirectory. MAGNETIC FIELD FILES The magnetic field files (CRnnnn.FPM) provided on these CDs are not the original files provided on the Aerospace agency tapes. The experimenter magnetic field files (which had neither the full time resolution nor the magnetic field intensity resolution of the original magnetometer outputs) were converted to field components in magnetometer sensor coordinates using the software and final calibration coefficient files provided by the magnetometer PI (Dr. Howard Singer, SEL). The original magnetic field files for orbits 6-350 were not readilly available, but the converted files were, so for the sake of uniformity, it was decided to provide the converted files instead of the originals. For those who might wish to get back to the original data, the source code (MAGMPC5.FOR) and calibration files (MAGnn.CAL) which were used to generate the .FPM files are provided. The original CR0237.MAG file is available on CD-8 for comparison with any results of an inversion program written by the user. A program which dumps the CRnnnn.FPM files is also provided on CD-35 (FPMTEST.EXE). This program prints out the UT, three magnetic field components in magnetometer coordinates, total B, and the pitch-angle calculated for the MEA (or a user-selected set of direction cosines). The source code, FPMTEST.FOR, is also provided. DATA FILES The data files have a complex format due to the fact that they are the outputs from three separate data processing units which worked independently. A program which extracts the data from all of the sensors processed by the DPU57 is provided on CD-35 (DPU57PLT.FOR) as an example of how to access the data and for those who might wish to look at data from the instruments controlled by DPU57 and the subcom data. The user is strongly cautioned to contact the individual PIs for information about their instrument which became available after the written documentation provided with these CDs [2,3,4,5,6,8,9,10,11] was printed. [1] Johnson, M. H. and J. Keirein "Combined Release and Radiation Effects Satellite (CRRES) Spacecraft and Mission," J. Spacecraft and Rockets, 29, No. 4, July-August 1992, pp.556-563. [2] Koga, R., S. D. Pinkerton and J. F. Fennell, "CRRES AFGL-701-11A (DPUA/MICS) Experiment Handbook, The Aerospace Corporation, P. O. Box 92957, Los Angeles, CA 90009, July 1990. [3] Koga, R., and S. D. Pinkerton, "CRRES AFGL-701-11B (DPUA/HMSB) Experiment Handbook, Report No. ATR-91(7216)-1, The Aerospace Corporation, P. O. Box 92957, Los Angeles, CA 90009, March 1992. [4] Koga, R., and S. D. Pinkerton, "CRRES AFGL-701-5,7 (DPU57) Experiment Handbook, The Aerospace Corporation, P. O. Box 92957, Los Angeles, CA 90009, July 1990. [5] Koga, R., S. S. Imamoto, N. Katz, and S. D. Pinkerton, "Data Processing Units for Eight Magnetospheric Particle and Field Sensors," J. Spacecraft and Rockets, 29, No. 4, July-August 1992, pp.574-579. [6] Wilken, B., W. Weiss, D. Hall, M. Grande, F. Soraas, and J. F. Fennell, "Magnetospheric Ion Composition Spectrometer Onboard the CRRES Spacecraft", J. Spacecraft and Rockets, 29, No. 4, July-August 1992, pp.585-591. [7] This instrument was abandoned by the PI (T. Fritz, Boston U.) on the basis that the penetrating electron background component produced so many false starts and stops of the timing circuitry in the instrument that no valid analysis was possible. Prior to attempting to use data from this instrument, contact the PI. [8] Young, D. T., B. L. Baraclough, D. J. McComas, M. F. Thomsen, K. McCabe and R. Vigil, "CRRES Low-Energy Magnetospheric Ion Composition Sensor", J. Spacecraft and Rockets, 29, No. 4, July-August 1992, pp.596-598. [9] Vampola, A., J. V. Osborn, and B. M. Johnson, "CRRES Magnetic Electron Spectrometer AFGL-701-5A (MEA)", J. Spacecraft and Rockets, 29, No. 4, July-August 1992, pp.592-595. [10] Korth, A., G. Kremser, B. Wilken, W. Guttler, S. L. Ullaland, and R. Koga, "Electron and Proton Wide-Angle Spectrometer (EPAS) on the CRRES Spacecraft", J. Spacecraft and Rockets, 29, No. 4, July-August 1992, pp.609-614. [11] Blake, J. B., and S. S. Imamoto, "Proton Switches", J. Spacecraft and Rockets, 29, No. 4, July-August 1992, pp.595-596. [12] Griffin, A., D. Delorey, and R. MacInerney, "CRRES Agency Tape Generation," GL TM No. 174, Air Force Geophysics Laboratory, Hanscom AFB, MA, October 1989. [13] MacInerney, R., R. Raistrick, E. Robinson, and A. Griffin, "CRRES Data Management Plan Data Processing Task," GL TM No. 130, Air Force Geophysics Laboratory, Hanscom AFB, MA, June 1986. [14] "CRRES Project Orbital Data Processing Task Aggency Tape Support Information," RMS Technologies, Inc., 70 Westview Street, Lexington, MA 02173, 8 August 1988. [15] Rodriguez, P., "Overview of the LASSII Experiment on the Combined Release and Radiation Effects Satellite," J. Spacecraft and Rockets, 29, No. 4, July-August 1992, pp.564-565. [16] Vampola, A., "Combined Release and Radiation Effects Satellite", J. Spacecraft and Rockets, 29, No. 4, July-August 1992, p.555. Copies of [2], [3], [4], [12], [13], and [14] are provided with the CDs.