DESCRIPTION |
This catalog file contains excerpts from Kissel et al, 2003.
Refer to this paper for an in-depth description of the
instrument.
SDN: This document has been updated for the Stardust-NExT (SDN)
mission, but mostly left intact from the prime mission data sets.
The prefix 'SDN:' typically precedes updated material.
Scientific Objectives
=====================
The main objective of CIDA was the analysis of particulates in the
interstellar dust stream and the cometary coma. Important
ancillary data were expected on dust flux rate, particle size
distribution and possibly particle mass densities.
Instrument Overview
===================
Cometary and Interstellar Dust Analyzer (CIDA) was a space-
qualified time-of-flight mass-spectrometer. Each impacting
particle provided a time-of-flight spectrum that can be
transformed into a mass spectrum once at least two peaks are
found to which well-known atomic mass unit values can be assigned.
CIDA comprised a silver target and single-stage ion reflector,
followed by an open electron multiplier.
The CIDA instrument analyzed the composition of individual
grains. As each particle impacted a silver plate, the high impact
energy due to the relative velocity of the spacecraft as it flies
through the coma caused the elements and molecular compounds in
the particle to become ionized. Using a fast time-of-flight mass
spectrometer, a complete set of ions was detected for each
impact, from a mass range of 1 (atomic hydrogen) up to a few
thousand atomic mass units, encompassing all elements in the
periodic table and many molecules, such as organic compounds.
This diagram illustrates CIDA mounting on the Stardust
spacecraft:
|| Dust Collector
|| Array
Solar Array Main ||
Shield +Z .-. Shield ||
.-. ^| | o
| |==========|====o===============o===============
`-' || |-------------------. . Solar
|| | |/| Array
|| | .-----. CIDA | |
<-------o| | | ' | | Return
+X +Y . __/ | | Capsule
| | `. `. |\|
| |--- `. `.---- -----' o---------
| | `. `. \_______/
`-' `.'`. Target
------> ------> ------> .' --------
Nominal . '
Incoming Particle `. ' 40 deg
direction during `.
Encounter `. Normal to
CIDA Target Plane
Operational Modes
=================
The on-board data handling system had been optimized for two
separate operation modes: the cruise mode and the encounter mode.
In the cruise mode, the expected event rates were so low that
complete sets of data were easily transferred to ground. In the
encounter mode, to be used during comet flyby, the impact-driven
data rate would essentially saturate the instrument and the
spacecraft's allocated data storage for CIDA of 200 megabits on
STARDUST. Therefore, in this mode the instrument data handling
optimized the size of the data passed to the spacecraft and
attempted to discard all events not obviously containing
meaningful data. In order to check the performance of the
selection process, every 16th triggered event was transmitted
unaltered, regardless of its contents. Every triggering event was
counted, but only a subset of data would be transferred to the
spacecraft and thence to the ground.
References
==========
Additional information about CIDA is available in the following
article published in the Journal of Geophysical Research in 2003
[KISSELETAL2003]:
Kissel, J., A. Glasmachers, E. Grun, H. Henkel,
H. Hofner, G. Haerendel, H. von Hoener, K. Hornung, E. K.
Jessberger, F. R. Krueger, D. Mohlmann, J. M. Greenberg, Y.
Langevin, J. Silen, D. Brownlee, B. C. Clark, M. S. Hanner,
F. Hoerz, S. Sandford, Z. Sekanina, P. Tsou, N. G. Utterback,
M. E. Zolensky, and C. Heiss, Cometary and Interstellar Dust
Analyzer for comet Wild 2, J. Geophys. Res., 108, (E10),
8114, 2003.
SDN: It is also available here:
http://astrochemistry.org/docs/Kisseletal2003.pdf
An example of interpreting CIDA time-of-flight spectrum data
contained in CIDA Spectrum EDF files archived in this PDS
data set is provided in the ``CIDA/STARDUST Example of Data
Calibration' document included with this data set.
Instrument Science Lead
=======================
Stardust prime mission to 81P/Wild 2:
Dr. Jochen Kissel
Max-Planck-Institut Fur Extraterrestrische Physik
SDN: Stardust-NExT extended mission to 9P/Tempel 1:
Dr. Johan Silen
Finnish Meteorological Institute.
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REFERENCES |
Kissel, J., A. Glasmachers, E. Grun, H. Henkel, H. Hofner, G. Haerendel, H. von
Hoerner, K. Hornung, E.K. Jessberger, F.R. Krueger, D. Mohlmann, J.M.
Greenberg, Y. Langevin, J. Silen, D. Brownlee, B.C. Clark, M.S. Hanner, F.
Hoerz, S. Sandford, Z. Sekanina, P. Tsou, N.G. Utterback, M.E. Zolensky, and C.
Heiss, Cometary and Interstellar Dust Analyzer for comet Wild 2, J. Geophys.
Res., 108, (E10), 8114, 2003, doi:10.1029/2003JE002091.
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