;file: GLLUVS2:[MARINER9.PDS_ARCHIVE.GEN_TEMPLATES]UVSINST.CAT ; ; Constructed July-August, 2000 - KES ; ; Edited April, 2002 - kes ; PDS_VERSION_ID = PDS3 LABEL_REVISION_NOTE = "Karen Simmons, April, 2002" RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 80 OBJECT = INSTRUMENT INSTRUMENT_HOST_ID = MR9 INSTRUMENT_ID = UVS OBJECT = INSTRUMENT_INFORMATION INSTRUMENT_NAME = "ULTRAVIOLET SPECTROMETER" INSTRUMENT_TYPE = "ULTRAVIOLET SPECTROMETER" INSTRUMENT_DESC = " This file was produced by the Mariner 9 (MM71 and M9) Ultraviolet Spectrometer (UVS) team at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado at Boulder. The UVS Principle Investigator (PI) is Dr. Charles A. Barth. Refer to the Mariner 1971 UVS instrument paper 'Ultraviolet Spectrometer Experiment',Vol 60, Space Science Reviews, pages 503-530, by C.W. Hord et al, for hardware and calibration information. See the instrument template and the science paper references in the publications template for additional information. The Mariner 9 Mars Ultraviolet Spectrometer (UVS) is an Ebert-Fastie design with an f/5 250mm slit occulting telescope. The telescope provides extensive (10^6 ) off-axis light rejection. Photomultiplier tubes (PMT's) are used for detectors. An electronic drive rotates the grating to sweep successive monochromatic spectral features across the exit slits and thus onto the PMT's each 3 seconds, so that spectra are obtained. During this 3 second period, 2.82 seconds are spent scanning the spectrum and 0.18 seconds are spent in the grating flyback, during which houskeeping data are placed on the telemetry stream; these measurements include a zero check, a gain calib- ration, a temperature, a 15 volt monitor (in the g channel) or a gain calib- ration (in the f channnel), and a high voltage monitor. The UVS used in Mariner 9 had two exit slits each equipped with its own PMT, each of which covered a specific wavelength region. The PMT current outputs reflect the light level observed by the UVS. The shorter wavelength channel, known as the G-channel, used a Cesium Iodide photocathode on its PMT to detect radiation from 1100-3383 Angstroms in first order and 1100-1692 A in second order. Similarly, the long wavelength device, known as the F-channel, used a Cesium Telluride photocathode (EMR-541 F) with a sapphire window to detect radiation in the first order bandpass from 1450-3528 Ang- stroms and in second order from 1450-1764 A. Both devices exhibit linear electronics, but the F-channel was equipped with an automatic gain-state control loop, which made it possible to handle the full dynamic range encountered in flight. Gain control was determined by a 40-ms integration of F-channel signal at 2890 A; this measurement fed a feedback control loop capable of selecting one of eight gain states ranging approximately in factors of three from 1 to ~2187 times the base gain. Gain changes were effected by increasing F-channel PMT voltage in proportion to the gain. The UVS produced 15 Angstrom resolution spectra, with fiducial marks and the F-channel gain state encoded in the telemetry. In addition to full spectra, the UVS also possessed the capability to sample only the 1216 Lyman-alpha feature; this capability was used during low data rate periods for the study of escape processes acting in the Mars atmosphere. Mariner Mars '71 was designed to place two spacecraft in orbit around Mars for the purpose of mapping, atmospheric studies, and surface thermal measurements. Mariner 8 failed to reach earth orbit. Mariner 9 succeeded in its mission goals, and produced Mars data during the period December 1971 through November 1972. The scientific objectives of the Mariner 9 UVS experiment were: (1) Ultraviolet cartography to measure local atmospheric pressure variations, local ozone variations, the UV wave of darkening, surface feature UV albedo variations with time and the yellow clouds, blue haze, and blue UV clearings observed in the Mars atmosphere. (2) Ultraviolet aeronomy to measure the composition and structure of the Mars upper atmosphere, the variability in atmospheric, ionospheric composition, and Hydrogen escape rates, and the distribution and variability of UV aurora. TABLE 1 Summary of Mariner 9 UVS characteristics ------------------------------------------------------------------------- Location UVS instrument Scan Platform Field of view Orientation Long axis of slit perpendicular to the camera scan lines Size (See comments below.) G-channel 0.19 by 1.9 deg F-channel 0.17 by 0.48 deg Optical configuration Ebert-Fastie grating spectrograph with f/5 250mm slit occulting telescope Detectors Photomultipliers G-channel EMR G with a Cesium Iodide photocathode and a Lithium Floride window F-channel EMR-541F with a Cesium Telluride photcathode and a Sapphire window Grating diffraction ?? lines / mm ?? coated Wavelength range G-channel 1100-1700 Angstroms F-channel 1700-3400 Angstroms Resolution 15 Angstroms Integration time 2.82 seconds for fiducial and spectrum Instrument UVS mass Logic module mass Total mass Power consumption Instrument Optics focal-length: 250 mm Principal Investigator: Charles A. Barth LASP, Campus box 392 University of Colorado, Boulder, CO 80309 (303)492-7502 Technical Notes The following information comes from a JPL Tech. Memorandum 33-569, written by John Farrar (the JPL instrument representative) on Oct 15 1972, which describes the development and testing of the UVS instrument: * 'The output of each PMT is integrated, sampled, stored, amplified, and converted into a pulsewidth every 5ms in response to the UVS 'read' pulse from the Data Automation System (DAS). * The total grating excursion of 16.5 deg requires 2.82s of the 3-sec period. The remaining 0.18s is used for grating flyback. * The G-channel FOV is 0.19 x 1.9 degrees; the F-channel is 0.19 x 0.55 degrees. * The F-channel views the spectrum in the first order from 1450 to 3528A and in the second order from 1450 to 1764A. The G-channel uses first order from 1100 to 3383 and 2nd order from 1100-1692. ' (End of Farrar's comments.) * The Icarus Vol 17, No.2, Oct,1972 paper by Hord, Barth,Stewart and Lane (on Mariner 9 UVS Photometry and Topography of Mars) states that the FOV is 0.17 x 0.48 deg. That's pretty close to Farrar's F-channel value. * The sensitivity of the F-channel was controlled by a count sampling technique which would decrease the sensitivity on the next spectrum if the count rates exceeded the 255 data counter maximum. This 'Gain State' level is registered in the engineering fiducial. (See the Fiducial table below and the MMRD.PRO software.) Calibration Description ======================= Besides the extensive ground pre-flight caibration, flight calibration consisted of stellar calibrations before Mars orbit insertion. Analysis of these data was published by R.C. Bohlin and others and incorporated into the calibration files available in the Calibration directory. Stellar flight calibrations were done during cruise; none of the raw data appear to have been archived in file format. The final calibration files are given in the calibration directory. Instrument Modes ================ The M9 UVS instrument obtained all data in the same operating mode resulting in identical records for the entire mission. A single wavelength photometer mode was available for Lyman-alpha studies but no data in this archive used that mode. ............................................................" END_OBJECT = INSTRUMENT_INFORMATION OBJECT = INSTRUMENT_REFERENCE_INFO REFERENCE_KEY_ID = "" END_OBJECT = INSTRUMENT_REFERENCE_INFO END_OBJECT = INSTRUMENT END