Data Set Overview : This dataset contains the raw and smoothed (averaged) instrument thermal telemetry for the entire EPOXI mission, from 04 October 2007 through 06 February 2011. Measurements were collected by 59 thermal sensors located in the HRII, HRIV, and MRI instruments, on the instrument platform, and on the solar wings of the Deep Impact flyby spacecraft.  Temperature Sensors : The raw and smoothed temperatures provided in this dataset are from two independent types of sensors:  1) One set is part of the spacecraft thermal subsystem which continuously control the thermal environment via the spacecraft telemetry stream, and  2) The other set records the measurements embedded in the science data image headers by the software on-board the spacecraft.  The spacecraft thermal subsystem are placed on active operating components and in critical locations on the HRI and MRI telescopes and in the HRII infrared spectrometer, the HRIV CCD, and the MRI CCD, as well as on the instrument platform and the two solar wings of the flyby spacecraft. All of these sensors, except those on the instrument platform and solar wings, are connected to side A or B of the flyby spacecraft's Thermal Interface Board (TIB). The sensors are used to monitor the thermal environment and, with the instrument heaters, provided a closed-loop temperature control via the telemetry stream. Measurements are recorded in the telemetry at various rates throughout the mission, from about once every minute to several times every hour whether the instruments were turned on or off.  The instrument thermal sensors are also placed on active operating components and in critical locations on the HRI and MRI telescopes and in the HRII infrared spectrometer, the HRIV CCD, and the MRI CCD instruments, sometimes in close proximity to sensors connected to the spacecraft thermal subsystem. However most of the instruments sensors only record measurements when an instrument is turned on. Measurements are recorded in the science image headers and in the telemetry at various rates throughout the mission, from about once every minute to several times every hour.  The Pictorial Atlas of Deep Impact and EPOXI) Instrument Thermal Telemetry document included in this dataset illustrates the location of the thermal telemetry points (sensors) are located. The thermal design of the instruments is described by Hampton, et al. (2005) [HAMPTONETAL2005]. The Deep Impact instrument calibration paper by Klaasen, et al. (2008) [KLAASENETAL2006] and the EPOXI instrument calibration paper by Klaasen, et al. (2011) describe how various temperatures affect the calibration of the HRII, HRIV, and MRI instruments. A draft of the Deep Impact document and summary of EPOXI document are included in this dataset.   Data : Raw thermal measurements received in the original telemetry stream from the flyby spacecraft were extracted, grouped by type ('T' for the spacecraft thermal subsystem and 'I' for the instrument sensors) and year of data acquisition, then formatted into fixed-width ASCII tables with filenames of {HRI,MRI}_RAW_{T,I}_YYYY.TAB and placed in the DATA/RAW/ path of this dataset. Each sensor measurement is provided as both raw data numbers and in the engineering unit (kelvin or degrees Celsius). No corrections or conversions were applied to the raw values.  The tools used to extract the measurements from the engineering telemetry have been run in a mode called 'report on change only with channel clear', such that for each sensor the tools excluded subsequent contiguous measurements that are the same as the previous measurement.  The raw thermal measurements were smoothed by averaging all measurements for each sensor within a 20-minute interval. The resulting averages were also grouped by type ('T' for the spacecraft thermal subsystem and 'I' for the instrument sensors) and year of data acquisition, formatted into fixed-width ASCII tables with filenames of {HRI,MRI}_SMOOTH_{T,I}_YYYY.TAB and placed in the DATA/SMOOTH/ path of this dataset. Each raw averaged temperature is provided in the engineering unit (kelvin or degrees Celsius), and a count of the values used to compute that average is included. No corrections or conversions were applied to the values.  This dataset contains raw and smoothed temperatures for these sensors which are illustrated in the Pictorial Atlas of Deep Impact & EPOXI Instrument Thermal Telemetry:  Spacecraft Thermal Subsystem, HRI 'T' Sensors --------------------------------------------- S/C AMMOS* Sensor# : Telem# : Sensor Description TS104 : T-0276 : HRI tele. barrel at center (first sensor) TS102 : T-0287 : HRI SIM bench at prisms (first sensor TS103 : T-0296 : HRI CCD plate assembly (first sensor) TS118 : T-0298 : HRI beam splitter TS131 : T-0302 : HRI primary mirror TS107 : T-0303 : HRI pre-amp box TS134 : T-0305 : HRI IR detector cooler (secondary radiator) TS114 : T-0306 : HRI IR focal plane array (primary radiator) TS116 : T-0327 : HRI electronics box TS110 : T-1777 : HRI tele. barrel at center (second sensor) TS108 : T-1792 : HRI SIM bench at prisms (second sensor) TS109 : T-1793 : HRI CCD plate assembly (second sensor) TS115 : T-1804 : HRI SIM bench at rear flexure TS135 : T-1806 : HRI telescope barrel baffle extension n/a : T-0339 : Panel underneath the instrument platform** TS1 : T-0275 : Back side of solar array wing 1, -Z direction** TS3 : T-0280 : Back side of solar array wing 1, +Z direction** TS2 : T-1776 : Back side of solar array wing 2, -Z direction** TS4 : T-1781 : Back side of solar array wing 2, +Z direction**  * AMMOS Advanced Multi-Mission Operations System ** Not shown in the Pictorial Atlas  Spacecraft Thermal Subsystem, MRI 'T' Sensors --------------------------------------------- S/C Sensor# : AMMOS# : Sensor Description TS132 : T-0277 : MRI optical bench at primary mirror TS106 : T-0284 : MRI CCD plate assembly (first sensor) TS105 : T-0299 : MRI telescope box at center bottom TS133 : T-1778 : MRI telescope box extension TS112 : T-1797 : MRI CCD plate assembly (second sensor) TS111 : T-1800 : MRI primary mirror TS113 : T-1805 : MRI pre-amp box TS117 : T-1819 : MRI electronics box  Instrument, HRI 'I' Sensors --------------------------- Instr Sensor# : AMMOS# : Sensor Description n/a : I-0221 : HRI instrument controller board n/a : I-0223 : HRI CCD signal processing board n/a : I-0225 : HRI IR signal processing board n/a : I-0227 : HRI mechanism and telemetry board n/a : I-0229 : HRI low voltage power supply board AD590PAMP : I-0231 : HRI pre-amp box PTS1 : I-0233 : HRI CCD plate assembly PTS2 : I-0235 : SIM bench at prism (close to prism #1) PTS3 : I-0237 : HRI primary mirror PTS4 : I-0239 : HRI secondary mirror; PTS5 : I-0241 : HRI SIM cover at motor bracket PTS6 : I-0243 : HRI SIM cover at the rear flexure PTS7 : I-0245 : HRI telescope barrel at primary mirror PTS8 : I-0247 : HRI telescope barrel baffle extension at 2nd mirror PTS9 : I-0249 : HRI SIM bench at motor bracket PTS10 : I-0251 : HRI CCD filter wheel and shutter motor bracket n/a : I-0342 : On-chip IR focal plane array  Instrument, MRI 'I' Sensors -------------------------- Instr Sensor# : AMMOS# : Sensor Description n/a : I-1221 : MRI instrument controller board n/a : I-1223 : MRI CCD signal processing board n/a : I-1227 : MRI mechanism and telemetry board n/a : I-1229 : MRI low voltage power supply board AD590PAMP : I-1231 : MRI pre-amp box PTS12 : I-1233 : MRI CCD plate assembly PTS12 : I-1235 : MRI optical bench at rear flexure PTS13 : I-1237 : MRI primary mirror PTS14 : I-1239 : MRI secondary mirror; PTS15 : I-1241 : MRI cover top plate PTS16 : I-1243 : MRI side panel radiator PTS17 : I-1245 : MRI telescope box top at primary mirror PTS18 : I-1247 : MRI telescope box top at secondary mirror PTS19 : I-1249 : MRI telescope box bottom at secondary mirror PTS20 : I-1251 : MRI CCD filter wheel and shutter motor bracket  Media Format : This data set is released in electronic format.

The EPOXI science team uses the smoothed temperatures to monitor and understand the thermal environment and its effects on the science image data. For example the HRII spectrometer is known to be very sensitive to temperature fluctuations.  Please note the HRI IR Spectral Imaging Module (SIM) bench temperatures recorded by the spacecraft thermal subsystem are known to be one to two degrees different, but more realistic, than the measurements collected by the instruments and recorded in the science data image headers. Because the HRII spectrometer is thermally sensitive, the calibration the calibration pipeline uses smoothed temperatures from the thermal telemetry when reducing IR data. See the Deep Impact instrument calibration paper by Klaasen, et al. (2008) [KLAASENETAL2006] for more information.  This dataset was peer reviewed and certified for scientific use on 15 August 2011.