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Double Star : PEACE

Key to PEACE Operations History Tables



Instrument mode example 1 (primary code)


Instrument mode example 2 (primary code)


Instrument mode example 3 (primary code)


Instrument mode example 4 (secondary code)



1. Energy Range Coverage

The sensor energy range coverage is indicated by the first two groups of characters,
e.g. in example 1 according to "88m28-60m00",  88m28-auto in example 3 etc

88m28-60m00 means that during the First Spin in each pair of spins, the sweep is covering the high end of the energy range (88 down to 28, see energy table) and during the
Second Spin in each pair of spins, the sweep is covering the low end of the energy range (60 down to 00). The symbol m implies MAR mode. This could also be l for LAR or h for HAR. The First and Second Spins may use identical energy range coverage (example 2)

88m28-auto means that the energy coverage of the Second Spin is determined
            autonomously, based on
the onboard spacecraft potential estimate and using the
            same sweep mode (e.g. MAR) as the First Spin,

        2. Data Return (DPU uses Primary Code)

The data return scheme is indicated by the remaining characters,
e.g. in example 1 according to "f-ab-15-s",  "f-aa-10-o" in example 3 etc

The DPU primary code generates 3DF data (indicated by f)  which is JPEG compressed.

            Data is always returned for the full energy range (a) for the First Spin in a pair. On the
            Second Spin it may again be retruned from the full energy range for that spin, or alternatively,
            data return may be restricted to that from the part that is non-overlapping with the energy range
            of the First Spin (b)

The telemetry data volume selected for data return is indicated by the numerical value at the
end of the string
(e.g. 10 in the example above) which can vary between 10 and 15. This is a rough measure of data compression quality.

             The character "s" or "o" indicates whether the onboard spacecraft potential estimation software is active "s" or not "o"

        3. Data Return (DPU uses Secondary Code)

            The DPU secondary code (derived from Cluster) generates PAD and 3DR data.

The PAD is not identical to the Cluster PAD, it contains 360° of pitch angle data.

          p        PAD        (pitch angle data)
          r         3DR        (reduced /8 resolution 3D data)

         The final code letter (e.g. examples 1 and 2) is used as follows

        s    indicates the spacecraft potential algorithm is on
        o    indicates the spacecraft potential algorithm is off

Return to the Operations Page

By Andrew Fazakerley
Last updated on 19/04/04  by  Andrew Fazakerley

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