The Cometary and Interstellar Dust Analyzer (CIDA) is a space qualified time-of flight mass spectrometer designed to study the elemental and chemical composition of the particles in the coma of comet P/Wild 2. CIDA works on the principle that dust grains hitting a target will produce ionized particles which can be influenced by magnetic fields and whose mass can be analyzed based on the time it takes them to pass through an electrostatic reflector. It can measure a mass range from 1 to a few thousand atomic mass units and can handle impact velocities of 25-55 km/s, typical for interstellar material, to 6 km/s for cometary dust.

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.

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.

extracted metadata from PDS3 catalog and
                    modified to comply with PDS4 Information Model

Stardust Cometary and Interstellar Dust Analyzer

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