New MEX-ASPERA-3 Ion Mass Analyzer High-Level Data In The ESA's Planetary Science Archive

Abstract: The European Space Agency’s (ESA) Mars Express (MEX) mission to Mars has been returning valuable scientific data for 21+ years.  This data is available to the public for free via the Planetary Science Archive (PSA), which houses the raw, calibrated, and higher-level data returned by the ESA’s planetary missions, including data provided by the various MEX instrument teams.  The Analyzer of Space Plasma and Energetic Atoms 3 (ASPERA-3) has provided several types of datasets throughout the mission, focusing on the ions and electrons in Mars' ionosphere as well as out into the solar wind environment surrounding Mars.

      For the Ion Mass Analyzer (IMA) subinstrument, the ASPERA-3 team has provided new level 4 and level 5 datasets which cover nearly the entirety of MEX's mission lifetime.  The level 4 sets contain data products covering the differential number flux of H⁺, He⁺⁺, O⁺, and O₂⁺ (in units of m^-2 s^-1 sr^-1 eV^-1) for the various sectors of the IMA detector.  The level 5 sets contain data products combining all the IMA sectors' data to yield temperature (eV), density (cm^-3), and velocity (km s^-1) information on these same 4 ion species.  All this data and more can be accessed at the PSA at: https://archives.esac.esa.int/psa/

Mars Express: MEX was inserted into Mars orbit in December 2003, though several instrument test observations also exist from the cruise phase of the mission, prior to arrival at Mars.  Thus, this long-lived Mars mission covers 21+ years of data with its 7 instruments.  Later in the mission’s lifetime, the camera used for the Beagle 2 lander separation was reactivated and used for public outreach.  Over time, the camera began to be used for scientific observations as well, making  MEX an unusual mission in that with this addition of the VMC instrument it now has more scientific instruments in operation than it was launched with.

The PSA user interface: The ESA’s PSA uses the Planetary Data System (PDS) format developed by NASA to store the data from its various planetary missions.  In the case of MEX, the data is stored in the PDS3 format, which primarily uses ASCII files to store and describe the data.  Newer missions, from ExoMars onward use the PDS4 data standard, which uses XML files to store the label information. 

       There are three primary ways in which to find the data.  One is the FTP area, which houses all the public data in the PSA.  Here, there are no advanced search capabilities, but it does provide access to all the supporting files and documentation for the various datasets.  When first searching for new data, users would benefit from using the Table View search interface [1].  Here the user can search using various parameters, such as mission name, target, instrument name, processing level, observation times, etc.  The Table View is also linked to the Image View, where users can view the browse images provided by the PI teams.  The Table View interface also has a section for “Free Search”, allowing one to use Contextual Query Language (CQL) to search over additional parameters.  These various search methods rely in part on the metadata provided by the instrument teams in the labels associated with each of the data products.

       Finally, there is also a Map View for viewing the footprints of data from those instruments where such calculations can be of some utility.  This Map View is built using GIS tools.

Conclusion: The delivery of the ASPERA-3 data provides new high level data on the ion populations in the vicinity of Mars.  This data can be freely accessed at the ESA’s PSA, at https://archives.esac.esa.int/psa/.  There are multiple ways of browsing the ASPERA-3 and other instrument teams’ data, including from other planetary missions, which will be explained in this poster.  The development of the PSA’s user interface is an ongoing project, and we welcome feedback from the community for suggestions on new ways to search this wealth of data.  Feedback and suggestions can be sent via our Help Desk system at:

https://support.cosmos.esa.int/psa/

Acknowledgements: The MEX Support Archive Scientists and the entire PSA team would like to extend their thanks to the ASPERA-3 team for their effort in continuing to deliver new data from Mars to the public via ESA’s PSA.  Our thanks go also to the European taxpayers, whose contributions to the European Space Agency enable the gathering and dissemination of this scientific knowledge, and preserving it for future generations of scientists to work on.

References: [1] Besse S. et al. (2018) Planetary and Space Science, 150, 131-140.