Data Set Information
DATA_SET_NAME DEEP IMPACT PREFLIGHT THERMAL-VACUUM 2 HRII/HRIV DATA
DATA_SET_ID DIF-CAL-HRII/HRIV-2-GROUND-TV2-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION This data set description was provided by Stephanie McLaughlin and Dennis Wellnitz (University of Maryland), who participated in the ground calibration tests of the Deep Impact instruments. Data Set Overview: This data set contains image and temperature data acquired during the preflight thermal-vacuum test (TV2) of High Resolution Instrument's Infrared Spectrometer (HRII) and Visible CCD (HRIV) for Deep Impact. The experiments performed during TV2 were designed by the Ball Aerospace team with input from the Deep Impact science team. TV2 was conducted by Don Hampton of Ball Aerospace. Several science team members were present at all times to assist with the experiments and perform real-time analysis of the data. The main objective of TV2 was to obtain calibration data for the HRII instrument: - Perform tests at the 3 nominal operating temperatures of the optical bench: 128K, 135K, and 141K. - Determine best focus at the nominal operating temperatures. - Obtain flat fields from various blackbody sources to measure the response of the FPA at different wavelengths. - Determine the non-linearity of the FPA. - Activate the internal calibration lamp. - Check for stray light. - Check for spectral motion caused by motion of the HRIV filter wheel. - Check adjustments made to the FPA spectral and spatial registrations based on TV1 results. - Check the spatial and spectral dispersion of the FPA. Also, during TV2, several calibration experiments were performed for the HRIV instrument: - Check focus. - Check co-alignment and co-focus with the HRII instrument. - Check registration of the parallel overclock columns and the serial overclock rows. - Test the photo-response of the CCD by using several calibrated blackbody sources and obtain flats. - Measure dark current as the CCD cools. - Measure bias. To meet these objectives, the instruments were tested in the Ball 8 thermal-vacuum chamber. A test bench was setup outside the chamber to direct light from external sources through the window of the chamber. TV2 activities are summarized in the following chart. FPA IR Opt. Date/(DOY) Temp(K) Bench(K) Tests ---------- ------- ------- ------------------------------------ 2002-08-15 N/A N/A HRII: Level check (227) HRIV: Level check 2002-08-17 120 104 HRII: Alignment check, Darks (229) 2002-08-18 ~88 ~136 HRII: Alignment, Focus, Internal (230) stimulator, Darks 2002-08-19 ~88 ~136 HRII: Alignment, Focus, Argon and (231) Krypton sources, Blackbody sources for flats, Darks 2002-08-20 ~88 ~136 HRII: Blackbody sources for flats, (232) Darks 2002-08-21 ~88 ~136 HRII: Tungsten lamp with various (233) filters and integrating spheres for flats, CO and CH4 gas cells, Darks 2002-08-22 ~88 ~136 HRII: Blackbody sources for flats, (234) Tungsten lamp for flats, Linearity, Various darks 2002-08-23 N/A N/A Warmup chamber for CCD hookup, (235) No data 2002-08-24 N/A N/A Hookup the CCD, Begin cooldown, (236) HRIV: Check CCD 2002-08-25 N/A N/A HRIV: Check CCD dark current (237) every 5 minutes as chamber cools, 2002-08-26 ~91 ~142 HRII: Alignment, Focus, Krypton (238) source, Darks HRIV: Co-alignment and co-focus with HRII 2002-08-27 ~90 ~141 HRII: Argon and Krypton sources, (239) Various sources for flats, Darks 2002-08-28 ~90 ~141 HRII: Linearity, Various sources (240) for flats, CH4 and N2 gas cells, Stray light, Darks HRIV: Filter wheel in motion while taking HRII darks, Begin cooldown to coldest temp 2002-08-29 ~86 ~130 Could not cool to 128K as in TV1 (241) HRII: Focus, Argon and Krypton sources, Various sources for flats, Darks HRIV: Focus, Darks, Co-focus with HRII 2002-08-30 ~86 ~130 HRII: CO, N2 and CH4 gas cells, (242) Various sources for flats, HJLM astronomy filters, Darks 2002-08-31 ~86 ~130 HRII: Linearity, Meteorite sample, (243) Various sources for flats, Stray light, Darks HRIV: Filter wheel in motion while taking HRII darks, Focus 2002-09-01/02 N/A N/A Calibrations finished; warmup (244-245) 2002-09-03 N/A N/A HRIV: Test with calibrated (246) visible source For more information about the mission, the HRII and HRIV instruments, and the anticipated flight data, see A'Hearn, et al. (2005) [AHEARNETAL2005], Hampton, et al. (2005) [HAMPTONETAL2005], and Klaasen, et al. (2005) [KLAASENETAL2005]. Parameters: HRII ---- The HRII spectral image data are in units of raw data numbers. For TV2, all seven of the HRII's image modes were tested: Image MinExp X-Size Y-Size #Images Mode# (sec) (pix) (pix) Output Binning Comments ----- ------ ------ ------ ------- ------- --------------------- 1 2.862 512 256 1 2x2 2 1.432 512 126 1 2x2 3 0.717 512 64 1 2x2 4 2.861 1024 512 1 1x1 5 2.865 512 256 1 2x2 6 1.432 1024 512 2 1x1 Reset then data frame 7 2.864 1024 512 1 1x1 Memory check mode In this table, MinExp is the frame-to-frame minimum exposure times, X-Size is spectral dimension and Y-Size is spatial dimension of the FPA. For all image modes except 6, the reset frame is automatically subtracted, on-chip, from the data frame and the result is output. For more information about the image modes, see Hampton, et al. (2005)[HAMPTONETAL2005]. Spectral and spatial registrations for the IR FPA were adjusted after TV1. During TV2, it was determined that the adjustments were correctly made. HRIV ---- The HRIV image data are in units of raw data numbers. The following image modes were defined and tested during TV2: Image MinExp X-Size Y-Size Mode# (ms) (pix) (pix) Binning Comments ----- ------ ------ ------ ------- ------------------------- 1 3.5 1024 1024 1x1 Shuttered 2 3.5 512 512 1x1 Shuttered 3 217.8 256 256 1x1 Not shuttered 4 98.4 128 128 1x1 Not shuttered 5 47.4 64 64 1x1 Not shuttered In this table, MinExp is the minimum exposure time and the term shuttered means the light blocker in the HRIV instrument is always used (opened and closed). For all modes, additional exposure time can be commanded. For unshuttered modes, a delay time (duration to wait before the start of the CCD readout) can also be commanded. For more information about the image modes, see Hampton, et al. (2005) [HAMPTONETAL2005]. Please note that the results from TV2 indicated the need for additional image modes with shorter minimum exposure times or without serial and parallel overclock areas. Four new image modes were defined and implemented for all of the Deep Impact CCDs after TV2. Data: Images ------ The data are in the form of FITS files with attached FITS headers and detached PDS labels. One data file contains one 2-dimensional HRII spectral image or HRIV visible image. The fastest-varying axis is considered the X axis and the slowest-varying, the Y axis. TV2 data filenames have this format: Iyymmdd_hhmmss_sss_xx.FIT where the 'yymmdd_hhmmss_sss' string the date, time and subseconds stamp provided by the ground-support computer when it stored the original data file. The clock on the ground-support computer was was set to local Mountain Daylight Savings time. The 'xx' string is valued with 'A' for all HRIV data, 'B' for HRII image modes 1-5 and 7, or 'B1' and 'B2' for the reset and data frames for HRII image mode 6. For TV2, the ground-support computer stored data files in a native image format, called 'IMG'. The raw data numbers were 14-bit and and left justified. A 100-byte image header was pre-pended to each data array. The 'IMG' data were converted to FITS at the Deep Impact Science Data Center (SDC) at Cornell University, using algorithms developed by Ball Aerospace for testing of the instruments and to allow real-time analysis of data during thermal-vacuum tests. During the conversion, raw data numbers were right justified to give the actual, true data numbers. Data in the 100-byte image header are captured in the FITS header. For TV2, all HRIV image modes have several columns of serial overclocks and several rows of parallel overclocks. However, during TV2, it was determined that the registrations of these areas on the CCD were not correct. Thus, the Field Programmable Gate Array (FPGA) for the CCD was changed after TV2. Instrument Temperatures ----------------------- Temperatures of various components of the HRII and HRIV instruments were automatically recorded every 5 minutes by a thermister monitor, a computer. Temperature data, in fixed-width ASCII table format, are available in the data directory. Time stamps in the temperature file are based on local Mountain Daylight Savings time and are within several minutes of the time stamps in the FITS filenames. It is important to note that the IR FPA temperatures recorded by the thermister monitor were adjusted by -3.26K before being stored in the temperature table. After thermal-vacuum 4 (TV4), Ball Aerospace personnel analyzed all IR FPA temperatures and determined the temperatures recorded by the monitor needed to be adjusted by -3.26K because the cable connected to this temperature point included about 18 inches of manganin wire which resulted in higher temperature measurements due to its higher electrical resistance. .Ancillary Data: The DOCUMENT directory provides the image log recorded during TV2. The log contains an entry for each image acquired during TV2 and includes image parameters such as mode and experiment type. The log includes a brief description of each type of experiment performed during TV2 and a summary of the experiments performed on each test date. The DOCUMENT directory also provides daily reports written by the test leaders and distributed to the test team and the science team. The reports describe in detail the test activities as well problems and successes encountered during TV2. The DOCUMENT directory includes the local PDS data dictionary used to produce the labels as well as sample IDL code used to read and extract temperatures from the TV2 temperature table. Media/Format: This data set is released as a logical data volume.
DATA_SET_RELEASE_DATE 2004-10-15T00:00:00.000Z
START_TIME 2002-08-15T03:39:47.000Z
STOP_TIME 2002-09-03T08:07:39.000Z
MISSION_NAME DEEP IMPACT
MISSION_START_DATE 2005-01-12T12:00:00.000Z
MISSION_STOP_DATE 2005-07-13T12:00:00.000Z
TARGET_NAME CALIBRATION
TARGET_TYPE CALIBRATION
INSTRUMENT_HOST_ID DIF
INSTRUMENT_NAME DEEP IMPACT HIGH RESOLUTION INSTRUMENT - IR SPECTROMETER
DEEP IMPACT HIGH RESOLUTION INSTRUMENT - VISIBLE CCD
INSTRUMENT_ID HRII
HRIV
INSTRUMENT_TYPE INFRARED SPECTROMETER
CCD CAMERA
NODE_NAME Small Bodies
ARCHIVE_STATUS ARCHIVED
CONFIDENCE_LEVEL_NOTE 1) The time stamp in the FITS filename can vary by several tens of seconds of the actual time the image was acquired. 2) Instrument temperatures should be extracted from the temperature table provided in this archive. While some temperatures appear in the PDS labels, these values were extracted from the FITS headers and are not reliable because of uncertainties about how the measurements were being recorded by the ground-support equipment used during TV2. However, temperatures recorded by the thermister monitor and provided in the temperature table are reliable according to Ball Areospace engineers and science team members who have used these data. 3) The images in this archive were used extensively by the science team and Ball Aerospace engineers to verify the instruments were operating within requirements and to calibrate the instruments. These data were reviewed internally by the Deep Impact project before release to the planetary community.
CITATION_DESCRIPTION Hampton, D.L., D.D. Wellnitz, and S.A. McLaughlin, DEEP IMPACT PREFLIGHT THERMAL-VACUUM 2 HRII/HRIV DATA, DIF-CAL-HRII/HRIV-2-GROUND-TV2-V1.0, NASA Planetary Data System, 2004.
ABSTRACT_TEXT This data set contains image and temperature data acquired during the preflight thermal-vacuum test (TV2) of the High Resolution Instrument's Infrared Spectrometer (HRII) and Visible CCD (HRIV) for the Deep Impact Mission.
PRODUCER_FULL_NAME STEPHANIE MCLAUGHLIN
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