PDS_VERSION_ID = PDS3 RECORD_TYPE = "STREAM" LABEL_REVISION_NOTE = " 2010-12-09 A.C.Raugh Extracted from the dataset.lbl file of the PDS1 test volume PHB_1001 for safing under PDS3. " OBJECT = DATA_SET DATA_SET_ID = "PHB2-M-TS-2-THERM/VIS-IMGEDR-V1.0" OBJECT = DATA_SET_INFORMATION DATA_SET_NAME = "PHOBOS 2 MARS TERMOSCAN THERMAL/VISIBLE IMAGING EDR V1.0" DATA_SET_TERSE_DESC = "Visible and IR thermal flux images from the Termosan instrument aboard the Phobos-2 spacecraft. These data are saved for historical reasons." ABSTRACT_DESC = " In February and March, 1989, the Termoskan instrument on board the Phobos '88 spacecraft of the USSR acquired a limited set of very high resolution simultaneous observations of the reflected solar flux (hereafter referred to as the visible channel) and emitted thermal flux (thermal infrared (IR)) from Mars's equatorial region. These are, so far, the highest spatial resolution thermal data ever obtained for Mars. Four slightly overlapping thermal panoramas (also called scans or swaths) cover a large portion of the equatorial region from 30 deg.S to 6 deg.N latitude. Simultaneous visible panoramas were taken during each of the four observing sessions; due to spacecraft memory limitations, visible channel processing was stopped early relative to the thermal channel for 2 of the sessions (2 and 4). Thus, the visible channel panoramas are shorter than the thermal panoramas for these sessions. These data are saved for historical reasons; they are not considered to be of archival quality. " CITATION_DESC = "UNK" START_TIME = 1989-02-11T10:55:00 STOP_TIME = 1989-03-26T17:49:50 DATA_SET_RELEASE_DATE = 1992 PRODUCER_FULL_NAME = "Yuri Gektin" DATA_OBJECT_TYPE = "IMAGE" DATA_SET_COLLECTION_MEMBER_FLG = "N" DETAILED_CATALOG_FLAG = "N" DATA_SET_DESC = " N.B.: These data are saved for historical reasons; they are not considered to be of archival quality. The 'edited data' referenced here are in the PDS data set PHB2-M-TS-2-EDITED-THRM/VIS-IMG-EDR-V1.0. Data Set Overview ================= In February and March, 1989, the Termoskan instrument on board the Phobos '88 spacecraft of the USSR acquired a limited set of very high resolution simultaneous observations of the reflected solar flux (hereafter referred to as the visible channel) and emitted thermal flux (thermal infrared (IR)) from Mars's equatorial region. These are, so far, the highest spatial resolution thermal data ever obtained for Mars. Four slightly overlapping thermal panoramas (also called scans or swaths) cover a large portion of the equatorial region from 30 deg.S to 6 deg.N latitude. Simultaneous visible panoramas were taken during each of the four observing sessions; due to spacecraft memory limitations, visible channel processing was stopped early relative to the thermal channel for 2 of the sessions (2 and 4). Thus, the visible channel panoramas are shorter than the thermal panoramas for these sessions. The instrument was fixed to the spacecraft with the optical axis pointing in the anti-solar direction. As a consequence, all observations are at approximately zero degrees phase angle and only daytime observations were acquired. Scan lines were acquired approximately going from North to South on the planet at a rate of 1 line per second. In the first session (taken Feb 11, 1989), the periapse altitude of the spacecraft's elliptical orbit was 1150 km and the resolution at nadir was approximately 300 m per pixel. The thermal and visible channel panoramas from this session exhibit longitudinal gaps of varying size between scan lines. Within each scan line (acquired in the North-South direction), however, full resolution and coverage were maintained. In the remaining three sessions (one taken on March 1, 1989 and two on March 26, 1989), the panoramas were acquired from a circular orbit of altitude 6300 km with a resolution at nadir of approximately 1.8 km per pixel. In these panoramas, line and frame scanning correspond; therefore, there are not significant gaps between scan lines and geometrical distortions primarily occur only because of the sphericity of the planet. Each image consists of 384 samples. The number of lines varies depending upon how long the instrument was on in any given panorama. The data is 8 bit data with dn values ranging from 0 to 255 for both the thermal and the visible channels. West is towards the top of each image file and North is to the right. All of the Termoskan data is contained in the 23 files of this data set. These files were delivered by the Institute of Space Devices Engineering (ISDE) (Moscow) to Caltech (Pasadena) in April, 1990 (except for session 1 which was delivered a few months earlier). The only difference between the files included here and those delivered from the Institute of Space Devices is that I have mirror flipped some of the files (resulting files all with the extension img: pan1irr1, pan1irr2, pan1vir1, pan1vir2, pan3irr1, pan3irr2, pan3irr3, pan3irr4, pan4vir1, and pan4vir2) as necessary. This was needed because some, but not all, of the image files were delivered from ISDE with the images appearing as Mars would appear if you saw it in a mirror. Each of the thermal channel files in this data set has 512 samples because in addition to the 384 data pixels per line there are also 126 pixels on one side of the image used for temperature stripes - each stripe representing the dn level for an additional 10 K. The visible channel files each have 384 pixels (except for session 1 which has filler pixels to 512 samples). Each of these files are fragments of larger panoramas. The pixels in the thermal channel files and visible channel files are not aligned (do not correspond to the same location on Mars) in this data set. See confidence level notes for more details and see the edited data set for complete panoramas that have been corrected so as to have the thermal data aligned geometrically with the visible channel data. PDS1 Data Set Parameters ======================== SAMPLING_PARAMETER_NAME = PIXEL SAMPLING_PARAMETER_RESOLUTION = 1 MINIMUM_SAMPLING_PARAMETER = N/A MAXIMUM_SAMPLING_PARAMETER = 384 SAMPLING_PARAMETER_INTERVAL = 1 MINIMUM_AVAILABLE_SAMPLING_INT = N/A SAMPLING_PARAMETER_UNIT = N/A DATA_SET_PARAMETER_NAME = DN NOISE_LEVEL = N/A DATA_SET_PARAMETER_UNIT = DIMENSIONLESS " CONFIDENCE_LEVEL_NOTE = " Confidence Level Overview ========================= A given line and sample in the raw thermal files will not correspond to the same location on Mars as the same line and sample in any of the visible channel files. Various quirks within the data and the raw data files that cause misalignment of the thermal and visible images are taken into account in the edited data set (file names ending in ed) but not in this raw data set. These include the following. Part of the misalignment problem is just due to the different raw files being of different length. In addition there are: offsets at the beginning of the scans, probably caused by data lines added to the files on Earth; dropped (missing) data lines in some of the thermal data and in some of the visible data (in most of the raw data no gaps are left to distinguish these missing lines); 2 to 3 pixel offsets in the N-S direction between the thermal and visible channels (caused at the spacecraft), i.e., pixels need to be added to the beginning of each thermal line to make the thermal samples line up with the visible channel samples. In addition to the alignment problems, the following occur in the data: noise in every eighth sample of the thermal channel amounting to a positive 1 or 2 dn increase (probably tied somehow into the calibration that was going on at a similar rate); sporadic single pixel spikes that occur occasionally within the data; occasional partial lines which appear corrupted; occasional whole lines with single dn values that appear to preserve geometry, but have no value as data; depending upon the panorama either the first or last of the 384 sample pixels is corrupted in the thermal channel, leaving at most 383 good samples per line; and two bright West-East lines (affecting the same samples in each line) in visible panorama 1 (possibly caused by reflections off the spacecraft?). The thermal channel appears to be very well calibrated to at least 3 K (Murray, et al. 1991). " END_OBJECT = DATA_SET_INFORMATION OBJECT = DATA_SET_HOST INSTRUMENT_HOST_ID = "PHB2" INSTRUMENT_ID = "TS" END_OBJECT = DATA_SET_HOST OBJECT = DATA_SET_MISSION MISSION_NAME = "PHOBOS 2" END_OBJECT = DATA_SET_MISSION OBJECT = DATA_SET_TARGET TARGET_NAME = "MARS" END_OBJECT = DATA_SET_TARGET OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "MURRAYETAL1991" END_OBJECT = DATA_SET_REFERENCE_INFORMATION END_OBJECT = DATA_SET END