Research Report 2018 Page !1 of !3

PLANETARY SCIENCE INSTITUTE

Research Report 2018 Anton B. Ivanov

MARSIS DATA PROCESSING.

I. Report on research and education activities This project concentrated on maintaining and improving MARSIS processing pipeline. MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) is a low frequency, pulse-limited radar sounder and altimeter used on the ESA Mars Express mission. It features ground-penetrating radar capabilities, which uses synthetic aperture techniques and a secondary receiving antenna to isolate subsurface reﬂections. In particular this work was split into the following tasks: • Support the production of MARSIS Level-2 Subsurface Data products. • Conduct Quality Checks of MARSIS Level-2 Subsurface Data. • Maintain MARSIS Level-2 Subsurface Database • Provide inputs to MARSIS Data Acquisition Targeting • Attend the MARSIS team meetings and report on MARSIS Level-2 Data Processing, as appropriate • Participate in the publication of MARSIS scientiﬁc results, as appropriate.

MARSIS level 2 data were continually updated and necessary interaction with JPL personnel was conducted to assure that resources to maintain the pipeline are present. For example, the web server had to receive considerable upgrade (change of operating system) to address cyber security concerns and storage had to be increased. These operations did not impact the pipeline itselft, but reception of level 1 data and distribution of final level 2 data had to be modified. Quality checks revealed that SPICE information (navigation and orientation for Mars Express) spacecraft was updated more often than previously thought, which resulted in inconsistencies in the data. Knowledge of the range to the surface and subsurface ground track affect strongly quality of the data. Many pieces of data have been re-processed to reflect changes and some additional procedures were introduced to monitor data and geometry quality.

A database (DB) of the orbits footprints and a viewer for the radargrams have been developed to allow an easier access to these data. The DB and the viewer are developed to be used with the QGIS Desktop application and to allow to easily select sections of orbits on the base of the geographic location or the geometric data and meta-data associated with the orbit. A plugin for MARSIS/SHARAD data was implemented inside the QGIS Geographic Information System, which is a free and open source desktop application. Example tracks are shown in Figure 1. The plugin has the following features: Research Report 2018 Page !2 of !3

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22 Legend

Signal to Noise Ratio 4.6712 - 14.4176 14.4176 - 24.1640 24.1640 - 33.9105 21 33.9105 - 43.6569 43.6569 - 53.4034

50 0 50 100 150 200 km 16

-135 -134 -133 -132 -131 -130 -129 -128 -127 -126

Figure 1. Example MARSIS tracks over the Olympus Mons in the QGIS frame. Colors, according to the legend, show relative quality (ionospheric impact) of the data.

• Radargram viewer :the radargrams selected in the main QGIS map are visualised. The section of the radargram related to the features selected on the map are highlighted on the radargram. The viewer can show a set of radar's data and a set of clutter simulation if available, one at a time, superposed or ﬂickering (with manual switch). Some preset look up table can be used. Radargrams can be zoomed and panned to better inspect it. • Radargram synchronised viewer: this viewer acts like the standard one with the difference that in this case, the radargrams related to different orbits are aligned by latitude and zoom and pan are synchronised. • Pseudo 3D viewer: in this viewer the radargrams are represented perpendicularly with respect to a ﬂat surface showing the map selected on the QGIS canvas. • ROI selection on the radargram: the standard viewer allow the user to move the highlighted selection on the radargram. Simultaneously, the selected features on the map will update accordingly. • Manual subsurface structure depth measurement: this tool allows, on the standard viewer, to manually draw lines following the surface and the subsurface structures. Then a QGIS vector layer including the measures of the subsurface structures depth in pixels and time can be generated. Another function allows to merge several layers related to different orbits in a single one to be used as a starting point to map generation.

The plug-in is written in the Python programming language and it is aimed, together with QGIS, to provide an easy way to select and visualise radargrams from MARSIS and SHARAD GPRs and to help mapping regions where subsurface structures are detected in radars' data. The plugin is freely available on https://github.com/ eSpaceEPFL/marsissharadviewer.

The meetings and reviews of the MARSIS and SHARAD science meetings were attended as appropriate. Research Report 2018 Page !3 of !3

II. Publications VESPA Workshop, Mapping Mars subsurface using a MARSIS and SHARAD plug-in for QGIS

Cantini F., Ivanov A. B., Mapping Mars North Pole subsurface using a MARSIS and SHARAD plug-in for QGIS, submitted to Planetary and Space Science, 2017

Ivanov A.B., Cantini, F, Properties of the Medussae Fossae formation from the joint analysis of MARSIS and SHARAD data, in preparation for Planetary and Space Science

MARSIS / SHARAD plugin to QGIS, open source software, available from GitHub

III. Awards and Honors None

IV. Service to the Science Community (e.g., advisory panels, society oﬃces) Proposal reviews (as expert) for the European Commission H2020 framework on Space TEC topic

VESPA implementation workshop 2017 (Europlanet action framwork) to educate on use of the MARSIS data, approximately 20 participants.

MARSIS workshop in China, 19 - 26 June, 2017, Space Science Institute, Taipa, Macau University of Science and Technology

V. Public outreach activities None on the MARSIS project.