PDS_VERSION_ID = PDS3 /* FILE: C10_FANS01_02.LOOK */ /* VERSION 1.0: Fri Oct 27 16:53:55 2000 SIMMONS */ RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 80 FILE_RECORDS = 462 PRODUCT_ID = "C10_FANS01_02.LBL" PRODUCT_NAME = "GALILEO EUV LOOK VECTOR DATA" OBSERVATION_ID = "C10_FANS01_0" PRODUCT_CREATION_DATE = 2000-10-26 SPACECRAFT_NAME = "GALILEO ORBITER" INSTRUMENT_NAME = "EXTREME ULTRAVIOLET SPECTROMETER" MISSION_PHASE_NAME = "JUPITER ORBIT OPERATIONS" TARGET_NAME = "IO-TORUS" START_TIME = 1997-304T08:20:48.692Z SPACECRAFT_CLOCK_START_COUNT = 1/04196991:00:0:0 ^TABLE = "E17A_MANS01_01.LOOK" DESCRIPTION = " This file was produced by the Galileo UVS/EUV team at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado at Boulder. Refer to the Galileo UVS/EUV instrument paper 'Galileo Ultraviolet Spectrometer Experiment', Vol 60, Space Science Reviews, pages 503-530, by C.W. Hord et al, for hardware and calibration information. Also see the EUV instrument template. This file contains position vectors utilized by the CITEP Io Torus software package. The Colorado Io Torus Emissions Package, or CITEP, is a computer package designed to simulate emissions from the Io plasma torus surrounding Jupiter. Specific information on the CITEP package can be found at: http://dosxx.colorado.edu/torus/citep.html. The data file associated with this geometry file gives the fixed pattern noise table in use during this observation, and the sequence information file gives the EUV command which specifies the number of scans per sector. The data contained in this file are position vectors based on the spacecraft's location relative to the torus at a specific time and the EUV instrument's field of view. The offset tilted dipole (OTD) used is based on Dessler, A. J., ed., Physics of the Jovian Magnetosphere, New York, Cambridge University Press, 1983, from his table on page 7. (The following is extracted from the Galileo Geometry and Graphics Software, GGGS, vector generation code: Model |M| Tilt Sys. III Long. Offset Offset Lat. Long. (deg) (deg) (Rj) (deg) (deg) D4 4.225 10.8 200.8 0.101 5.1 155.6 OTD 4.35 9.5 208.8 0.068 -12.6 174.2 O4 4.28 9.6 201.7 0.131 -8.0 148.57 P11A 4.208 10.0 198.8 0.108 4.8 143.07 |M| = magnetic field strength (?) Tilt & Sys. III Long. = the magnetic field axis Tilt towards the Sys. III Long. of Jupiter wrt Jupiter spin axis Offset (Rj, Lat., Long.) = the offset of the torus axis wrt magnetic field axis Note that the the O4 & P11A models are actually spherical harmonic models with the equivalent System III OTD values as listed above. The D4 and OTD values listed above are "true" OTD models. The code in this routine makes use of the O4 model offset values as shown above. However, the values for the Tilt and Sys. III Long. differ.) The beginning of the file gives the UTC time, SCLK time and the spacecraft's position relative to the center of the torus. The time used to determine the vectors is the approximate midpoint of the EUV integration summation period. Cross-check the summation packet time with the time given in the LOOK file. Each vector contains the following data: Vector = [radius (km), theta (deg), z (km)] The radius is the perpendicular distance (km) from the Io torus center to the intersection of the EUV look vector with the torus. Theta is the corresponding Jupiter W. Longitude (deg) of the intersection of the EUV look vector and the torus point. 'z' is the altitude (km) that the intersection point lies above or below the plane of the torus. Each data entry in the file represents one EUV detector scan of one EUV sky-sector. Each entry gives the four corner vectors for the EUV sky-sector boundary and the sector's boresight. The following is an example from the E15_MANS01_09.LOOK;1 file: UTC Time : 1998-154 // 00:14:30.288 SCLK Time : 1/04502708:00:0:0 Spacecraft position = (-383215.02, 1640355.2, 765540.09) (km) Aft - Engine side Forward - Antennae side Columns go from Aft to Forward Rows go from first to second BEGIN-OF-DATA --- Sector 1, Scan 1, Vector = [radius (km), theta (deg), z (km)] Aft (first) = ( 577384.51, 124.72968, -141727.03 ) Forward (first) = ( 550564.88, 123.89970, -141106.73 ) Aft (second) = ( 577976.12, 124.55295, -129475.83 ) Forward (second) = ( 551174.03, 123.71477, -128794.08 ) Boresight = ( 564289.57, 124.22163, -135289.03 ) Col: 1, Row: 1 = ( 573219.62, 124.49988, -135501.61 ) Col: 2, Row: 1 = ( 564289.57, 124.22163, -135289.03 ) Col: 3, Row: 1 = ( 555345.39, 123.94373, -135067.57 ) --- Sector 2, Scan 1, Vector = [radius (km), theta (deg), z (km)] Aft (first) = ( 577976.12, 124.55295, -129475.83 ) Forward (first) = ( 551174.03, 123.71477, -128794.08 ) Aft (second) = ( 578576.97, 124.39377, -117200.86 ) Forward (second) = ( 551791.41, 123.54832, -116457.72 ) Boresight = ( 564894.58, 124.04990, -122994.22 ) Col: 1, Row: 1 = ( 573818.93, 124.33069, -123227.59 ) Col: 2, Row: 1 = ( 564894.58, 124.04990, -122994.22 ) Col: 3, Row: 1 = ( 555956.06, 123.76938, -122752.60 ) --- Sector 3, Scan 1, Vector = [radius (km), theta (deg), z (km)] . . repeats until the end of the file: --- Sector 24, Scan 1, Vector = [radius (km), theta (deg), z (km)] Aft (first) = ( 591930.88, 125.03528, 141698.23 ) Forward (first) = ( 565210.89, 124.24026, 143717.54 ) Aft (second) = ( 592614.47, 125.25032, 153872.44 ) Forward (second) = ( 565886.12, 124.46684, 155951.63 ) Boresight = ( 578926.20, 124.74518, 148820.30 ) Col: 1, Row: 1 = ( 587826.87, 125.00872, 148134.35 ) Col: 2, Row: 1 = ( 578926.20, 124.74518, 148820.30 ) Col: 3, Row: 1 = ( 570010.41, 124.48246, 149500.58 ) END-OF-DATA Data computed on : Tue May 2 15:48:42 2000 SP Kernels loaded: TORUS1:[GLL_RAW.SPICE_KERNELS.SPK]SPK_PLANETS_DE202.BSP_1;1 TORUS1:[GLL_RAW.SPICE_KERNELS.SPK]SPK_S971125A.BSP_1;1 TORUS1:[GLL_RAW.SPICE_KERNELS.SPK]SPK_S970401A.BSP_1;1 TORUS1:[GLL_RAW.SPICE_KERNELS.SPK]SPK_S980602A.BSP;1 TORUS1:[GLL_RAW.SPICE_KERNELS.SPK]SPK_S980723A.BSP;1 TORUS1:[GLL_RAW.SPICE_KERNELS.SPK]SPK_S990706A.BSP;1 TORUS1:[GLL_RAW.SPICE_KERNELS.SPK]SPK_S991014A.BSP;1 Rotation Rate : 3.1500000 rev/min Spacecraft distance to body center : 1850316.4 km Body center Ra : 103.14944 deg Body Center Dec : 24.439660 deg end of file example Aft refers to the engine side position of the EUV sector being scanned. Forward refers to the antennae side of the sector. The boresight is the center of the EUV sector. 'First' and 'second' refer to the relative 'top' and 'bottom' of the sector (see diagram below) where the 'top' is the edge toward the North Pole crossing (defined as 0 sky degrees) as the EUV sky-sectors sweep down through the sky. A single EUV Sky-sector: Each of the 5 points are marked with an 'x' Aft First x------------------------x Forward First | Boresight | | x | | | Aft Second x------------------------x Forward Second A diagram of the EUV instrument's field of view (FOV) is shown below: Begins at a commanded angle after the North Pole Crossing AFT Forward Column # ------------------------- | | Sector 1 | 1 2 3 | ------------------------- | | Sector 2 | 1 2 3 | ------------------------- | | Sector 3 | 1 2 3 | ------------------------- | | . . (repeats) . | | ------------------------- | | Sector 24 | 1 2 3 | ------------------------- If more than one EUV 'scan per sector' is commanded then the second scan data is presented after the Scan 1 data and within the same Sector set. The number of scans per sector and the number of sectors are commandable (see the EUV instrument template); increasing the number of scans per sector increases the size of the sector on the sky. ............................................................." OBJECT = TABLE NAME = "EUV LOOK VECTOR GEOMETRY" INTERCHANGE_FORMAT = ASCII ROWS = 462 COLUMNS = 10 ROW_BYTES = 80 ^STRUCTURE = "EUV_LOOK.FMT" DESCRIPTION = " The data table consists of position vectors based on the spacecraft's position relative to the torus at a specific time. There are three position vectors for each EUV scan and sector. Each vector provides distance, longitude and altitude information." END_OBJECT = TABLE END