PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 46 FILE_RECORDS = 4500 ^TABLE = "GREOL.TAB" DATA_SET_ID = "GIO-C-GRE-3-RDR-GRIGG-SKJELL-V1.0" PRODUCT_ID = "GRE-GREOL-199512" PRODUCT_NAME = "Giotto Extended Mission GRE Open-Loop Results" PRODUCT_CREATION_TIME = 1995-12 TARGET_NAME = "26P/GRIGG-SKJELLERUP 1 (1922 K1)" INSTRUMENT_HOST_NAME = "GIOTTO" INSTRUMENT_NAME = "GIOTTO RADIOSCIENCE EXPERIMENT" START_TIME = 1992-07-10T15:27:30.00 STOP_TIME = 1992-07-10T15:33:30.00 SPACECRAFT_CLOCK_START_COUNT = "UNK" SPACECRAFT_CLOCK_STOP_COUNT = "UNK" DESCRIPTION = "This file contains open-loop data from the Giotto Radio Science Experiment (GRE) flown aboard the Giotto spacecraft during the flyby of comet P/Grigg-Skjellerup. The time span cover the range +/- 3 minutes around closest approach. The data were received by station 63 in Madrid." RECORD_FORMAT = "I2,1X,I2,1X,F5.2,1X,F9.3,1X,F6.3,1X,F7.5,1X,F7.2" OBJECT = TABLE NAME = "OPEN-LOOP RESULTS" INTERCHANGE_FORMAT = ASCII COLUMNS = 7 ROW_BYTES = 46 ROWS = 4500 DESCRIPTION = "This table lists time, frequency and signal information every 0.08 seconds for a period +/- 3 minutes around closest approach. The time indicated is UTC, tagged at the instant of ground reception (i.e., GRT). The time of closest approach corresponds to 15:30:36 GRT or 15:18:44 SCET (spacecraft event time)." OBJECT = COLUMN NAME = HOURS BYTES = 2 DATA_TYPE = ASCII_INTEGER START_BYTE = 1 FORMAT = "I2" UNIT = "HOURS" DESCRIPTION = "Hour at the end of the measurement (GRT)" END_OBJECT OBJECT = COLUMN NAME = MINUTES BYTES = 2 DATA_TYPE = ASCII_INTEGER START_BYTE = 4 FORMAT = "I2" UNIT = MINUTES DESCRIPTION = "Minutes at the end of the measurement (GRT)" END_OBJECT OBJECT = COLUMN NAME = SECONDS BYTES = 5 DATA_TYPE = ASCII_REAL START_BYTE = 7 FORMAT = "F5.2" UNIT = SECONDS DESCRIPTION ="Seconds at the end of the measurement (GRT)" END_OBJECT OBJECT = COLUMN NAME = FREQUENCY BYTES = 9 DATA_TYPE = ASCII_REAL START_BYTE = 13 FORMAT = "F9.3" UNIT = "HERTZ" DESCRIPTION = "Bandpass center frequency. Dr. Martin Paetzold writes (private communication): The predicted received frequencies are generated from the knowledge of the transmitted frequency and the topological doppler frequency which depends on the radial velocity between spacecraft and ground station. Unfortunately the transmitted frequency is generated by a rather noisy oscillator on board Giotto, which drifts in frequency. These drifts are unpredictable, but are at least close to linear for short time segments, including the time of close approach. The ground station provides already the residual frequency. This means that the absolute downlink frequency measurement really doesn't give us any additional information about the comet/spacecraft interaction. It is only the CHANGE of frequency during the flyby that is used in the scientific analysis. No baselines were subtracted in these data." END_OBJECT OBJECT = COLUMN NAME = SNR BYTES = 6 DATA_TYPE = ASCII_REAL START_BYTE = 23 FORMAT = "F6.3" UNIT = "dB" DESCRIPTION = "Signal-to-noise ratio" END_OBJECT OBJECT = COLUMN NAME = NOISE BYTES = 7 DATA_TYPE = ASCII_REAL START_BYTE = 30 FORMAT = "F7.5" UNIT = "VOLTS*VOLTS/HERTS" DESCRIPTION = "Noise level" END_OBJECT OBJECT = COLUMN NAME = POWER BYTES = 7 DATA_TYPE = ASCII_REAL START_BYTE = 38 FORMAT = "F7.2" UNIT = "dBm" DESCRIPTION = "Received signal power" END_OBJECT END_OBJECT = TABLE END