
    Bundle Description for the MAVEN NGIMS Archive Bundle
    ===================================================

    Overview
    ========

    The MAVEN NGIMS archive bundle includes all data taken by the Neutral Gas and
	Ion Mass Spectrometer (NGIMS) instrument aboard the Mars Atmosphere and Volatile
	Evolution (MAVEN) spacecraft.  The MAVEN mission and spacecraft are described 
	in the MAVEN mission and spacecraft description documents, available in the 
	MAVEN archive bundle.
    These data are generated by ionizing the neutral gas and then selectively
    filtering and detecting the resulting ions according to their
    mass-to-charge ratio.  The NGIMS instrument is described in the MAVEN NGIMS
    Software Interface Specification (SIS) which is available in the document 
	collection.

    Data Collections
    ===============

    The data is included in two different processing levels, raw and
    calibrated.  Raw data are the original data from the instrument.
    Calibrated data are raw data converted to engineering units and corrected for
    detector response.  Derived data are processed abundances and higher level products. 
	The calibration process is also described in the NGIMS 
	SIS document. Flight data are available in both raw and calibrated form
	in the data_raw and the data_calibrated collections. Data acquired during 
	instrument integration, calibration and testing is made available in the 
	calibration collection in a raw form. Derived and resampled atmospheric abundances
	and scale heights are high level products that are available  in the data_derived 
	and data_resampled collections

    The following table describes the NGIMS products in the calibration, data_raw, and
    data_calibrated collections:

    Data Definitions Table
    ----------------------------------------------------------------------------
     Product Name                 Description                         File Label
    ------------                  -----------                         ----------	
	Calibration Housekeeping	  Raw housekeeping packets	gnd_hk
    Calibration Science	          Raw science packets	              gnd_sci
    Calibration Message Log       Raw message log	                  gnd_msg
    Calibration Markers	          Raw marker file                     gnd_mkr
    Raw Housekeeping	          Raw housekeeping packets	          raw_hk
    Raw Science	                  Raw science packets	              raw_sci
    Raw Message Log	              Raw message log	     	          raw_msg
    Raw Markers	                  Raw marker file	                  raw_mkr
    Calibrated Housekeeping	      Calibrated housekeeping packets	  cal_hk
    Calibrated Science	          Calibrated science packets	      osion/osnb
    Calibrated Message Log        Calibrated message log	     	  cal_msg
    Calibrated Markers	          Calibrated markers lists            cal_mkr
    Derived Densities	         Neutral and Ion abundances          ion, cso, csn
    Resampled Abundances	      Altitude resampled abundances	      res_den
    Resampled Scale Heights	      Scale-heights and temperatures      res_sht
    ----------------------------------------------------------------------------

    Document Collection
    ===================

    The document collection contains the following documents. It also
    contains an inventory of its contents.

    Document                 Description
    --------                 -----------
    NGIMS SIS                The Software Interface Specification,
                             including a full description of the data
                             formats and contents, and a brief description of the
                             NGIMS instrument. This document provides detailed 
							 of the instrument calibration results necessary to
							 process the NGIMS data.

    Context Collection
    ==================

    The context collection contains pointers to the context information
    including mission, spacecraft, instrument, and bundle descriptions.


    XML_schema Collection
    =================

    The schema collection contains pointers to all schemas used to generate
    the MAVEN NGIMS bundle.
