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Data Set Overview
=================
This data set contains raw temperature measurements from telemetry
for the EPOXI mission from 27 sensors located in the HRII, HRIV,
and MRI instruments and on the HRI and MRI telescopes, instrument
platform, and solar wings of the Deep Impact flyby spacecraft.
The data for this version were collected from 17 December 2007
through 31 December 2008, during the first cruise and EPOCh phases
of the mission as well as the early part of the second cruise
phase. Future versions of this data set will include thermal data
from the remaining part of the second cruise phase and the
103P/Hartley 2 encounter phase (DIXI) of the mission.
Most of the sensors are part of the spacecraft thermal subsystem which
continuously control the thermal environment via the spacecraft
telemetry stream. Temperatures are recorded in the telemetry at
various rates throughout the mission from several times every hour to
as frequently as once every minute depending whether the instruments
are turned on or off. It is important to note that 1) these thermal
sensors are independent of those used to record the measurements that
are embedded in the science data image headers by the software
on-board the spacecraft and 2) the IR Spectral Imaging Module (SIM)
bench temperatures recorded in the telemetry are known to be one to
two degrees different, but more realistic, than the measurements
captured in the image headers. See the Deep Impact instrument
calibration paper by Klaasen, et al. (2008) [KLAASENETAL2006] for
more information.
These data are used by the EPOXI science team to monitor and
understand the thermal environment and to calibrate the HRII
instrument which is very sensitive to temperature fluctuations.
Data
====
Thermal measurements received in the original telemetry stream from
the flyby spacecraft were extracted and formatted into two fixed-width
ASCII tables with detached PDS labels; There is one table and label
for each thermal sensor. No corrections or conversions were applied
to the raw temperatures. The tools used to extract the measurements
from the engineering telemetry have been run in a mode called `report
on change only', i.e. for each sensor the tools excluded subsequent
contiguous measurements that are the same as the previous measurement.
Please note the HRI IR Spectral Imaging Module (SIM) bench
temperatures recorded in the telemetry are known to be one to two
degrees Celsius different than the measurements collected by the
instruments and recorded in the science data image headers.
HRI Temperatures Tables
-----------------------
Raw measurements from each of the 14 different temperature sensors
located at various points on the HRI telescope, the HRI IR
spectrometer (HRII) which includes the SIM, and the HRI visible CCD
(HRIV) are provided as separate fixed-width ASCII tables, by AMMOS
number, with detached PDS labels. Additionally raw measurements
from a sensor in the panel underneath the instrument platform and
four sensors located on the back side of the two solar wings on the
flyby spacecraft are also provided as separate fixed-width ASCII
tables, by AMMOS number, with detached PDS labels.
S/C
Sensor# : AMMOS# : Sensor Description
TS104 : T-0276 : HRI tele. barrel at center (first sensor, TIB side A)
TS102 : T-0287 : HRI SIM bench at prisms (first sensor, TIB side A)
TS103 : T-0296 : HRI CCD plate assembly (first sensor, TIB side A)
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,TIB side B)
TS108 : T-1792 : HRI SIM bench at prisms (second sensor, TIB side B)
TS109 : T-1793 : HRI CCD plate assembly (second sensor, TIB side B)
TS115 : T-1804 : HRI SIM bench at rear flexure
TS135 : T-1806 : Baffle extension on the HRI telescope barrel
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
MRI Temperatures Tables
----------------------
Raw measurements from each of the eight different temperature sensors
located at various points on the MRI telescope and the MRI visible
CCD are provided as separate fixed-width ASCII tables, by AMMOS
number, with detached PDS labels.
S/C
Sensor# : AMMOS# : Sensor Description
TS132 : T-0277 : MRI optical bench at primary mirror (TIB side A)
TS106 : T-0284 : MRI CCD plate assembly (first sensor, TIB side A)
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, TIB side B)
TS111 : T-1800 : MRI primary mirror (TIB side B)
TS113 : T-1805 : MRI pre-amp box
TS117 : T-1819 : MRI electronics box
The spacecraft sensor numbers (TSnnn) and AMMOS numbers (T-nnnn),
Advanced Multi-Mission Operations System) are provided to help
researchers locate the thermal sensors illustrated in the Pictorial
Atlas of Deep Impact (& EPOXI) Instrument Thermal Telemetry document
which included in this data set. Again, it is important to note these
temperature sensors are independent of those used to record
measurements that were embedded in the science data image headers
by the software on-board the spacecraft.
Temperature Sensors
===================
Thermal sensors 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. A ll 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.
To see where the thermal telemetry points are located, please refer
to the Pictorial Atlas of Deep Impact (& EPOXI) Instrument Thermal
Telemetry document included in this data set. For a discussion of
the thermal design of the instruments, see Hampton, et al. (2005)
[HAMPTONETAL2005]. The Deep Impact instrument calibration paper
by Klaasen, et al. (2008) [KLAASENETAL2006] describes how various
temperatures affect the calibration of the HRII, HRIV, and MRI
instruments. Drafts of these two documents are included in this
data set.
Media Format
============
This data set is released in electronic format.
This data set overview was prepared by Stephanie McLaughlin with input
from Brian Carcich, the data supplier, and Donald Hampton, the
instrument engineer. Plots in the document directory were provided
by Lori Feaga.
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