PDS_VERSION_ID = PDS3

LABEL_REVISION_NOTE  = "2010-05-27, SONC, initial release "

RECORD_TYPE                       = STREAM

OBJECT     = INSTRUMENT
  INSTRUMENT_HOST_ID = RL
  INSTRUMENT_ID      = "PTOLEMY"

  OBJECT     = INSTRUMENT_INFORMATION
    INSTRUMENT_NAME = "PTOLEMY - GAS CHROMATOGRAPH ISOTOPE RATIO MASS
                       SPECTROMETER"
    INSTRUMENT_TYPE = "GAS DETECTOR"
      /* RLC was "GAS ISOTOPE RATIO ANALYSER" */
    INSTRUMENT_DESC = "

      Instrument Overview
      ===================
      Ptolemy is part of the Rosetta instrument payload and is one of
      two evolved gas analysers of the Lander space-craft Philae. It
      provides data on the chemical and isotopic composition of the
      nucleus of comet 67P/Churyumov-Gerasimenko.


      Scientific Objectives
      =====================
      The aims of Ptolemy are
      i) the determination of the chemical composition (accuracy 10%
         and mass range 10-150 Daltons) and
      ii) light element (H, C, N, O) isotopic composition of major
          components with an accuracy of 1% of volatile and
          refractory cometary components


      Calibration
      ===========
      The calibration of individual components (pressure sensors and
      temperature sensors) is incorporated in the EGSE software.
      Mass calibration of the mass spectrometer is achieved by using
      argon gas as a mass marker in the helium gas supply system.


      Operational Considerations
      ==========================


      Detectors
      =========
      The detector is an ion trap mass spectrometer.


      Electronics
      ===========
      Details on the electronics of the instrument are described in
      the Ptolemy ADP.

      Location
      ========
      Ptolemy is mounted on the large Pi-plate in the warm
      compartment of Philae.  Samples are delivered by the Sample
      Drilling and Distribution unit (SD2) to ovens located on the
      balcony of Philae.

      Operational Modes
      =================
      Ptolemy operates in three distinct modes; Safe, Standby and
      Science.  Housekeeping data is collected during all three
      modes.  On power on, Ptolemy enters Safe mode.
      Safe mode is used for processor memory management such as
      loading new science sequences and check memory commands. The
      only mode change is from Safe to Standby mode.
      Standby mode is used to enable components for use during the
      subsequent Science mode.  Ptolemy can be commanded to operate
      a Science mode sequence or be returned to Safe mode.
      Science mode operates a previously loaded sequence. At the
      successful completion of a Science mode sequence, Ptolemy
      returns to Standby mode.

      Subsystems
      ==========
      The subsystems are: Sample Collection (SC), Gas Distribution
      and Processing System (GDPS), Gas Chromatography (GC), and
      Mass Spectrometer (MS).
      Sample collection consists mainly of the SD2 instrument which
      acquires solid samples and distributes them to Ptolemy ovens on
      the carousel.  Gaseous samples can also be collected by an oven
      filled with molecular sieve or be analysed directly by the mass
      spectrometer.
      The Gas Distribution and Processing System consists of heaters,
      valves temperature and pressure sensors in order to prepare the
      sample for direct MS analysis or for injection into one of
      three columns of the GC system.  The GDPS also contains
      reference materials so that the comet samples can be directly
      compared with terrestrial compounds of known isotopic value.
      The Gas Chromatography system includes 3 GC columns to separate
      the sample into individual components as well as the helium
      carrier gas required for gas chromatography.
      The Mass spectrometer analyses compounds giving a mass spectrum
      as they are eluted from a GC column.
      The sub-systems are described in more detail in Morse et al,
      2009.


      Measured Parameters
      ===================
      The Ptolemy GC measures the retention times of molecular
      species in separation columns, the Ptolemy MS measures the mass
      (Daltons) of ionised fragments of molecular species. The
      temperature and pressure of various components are monitored.
    "
  END_OBJECT = INSTRUMENT_INFORMATION


  OBJECT     = INSTRUMENT_REFERENCE_INFO
    REFERENCE_KEY_ID ="WRIGHTETAL2007"
  END_OBJECT = INSTRUMENT_REFERENCE_INFO


END_OBJECT = INSTRUMENT

END