The Rosetta Science Archive: Preparing for Legacy Science

Introduction: 30 September 2016 marked the end of the Rosetta mission as the spacecraft came to rest on the surface of comet 67P/Churyumov-Gerasimenko.  Although this marked an end to the spacecraft’s active operations, intensive work has continued for several years, with the instrument teams updating their science data in response to recent scientific reviews and delivering them for ingestion into ESA’s Planetary Science Archive (PSA) [1].

 

This presentation will outline the final status of the Rosetta archive, as well as highlighting some of the enhancement activities that have been completed in 2020 and the work undertaken to finalise and close out the Rosetta archive.

 

Status of the Rosetta data in the Planetary Science Archive: All science data from the Rosetta mission are hosted jointly by the Planetary Science Archive (PSA) at ESA (http://psa.esa.int) [1], and by NASA’s PDS Small Bodies Node (SBN). 

 

Rosetta was an extremely complex and challenging mission to archive [2].  To help manage some of these complexities a total of nine independent data reviews have taken place over the course of the mission.  Five of these have taken place after the closure of the nominal mission.  In addition, a number of small individual reviews have been held to assess the final deliveries from some of the teams using their latest pipelines.  In combination, these reviews have assessed the complete data holdings from Rosetta, and closely reviewed the updated outputs from the enhanced archiving activities, discussed in the following section.  This series of reviews has ensured that the archive is now ready for the long-term.

 

Rosetta Enhanced Archiving Activities: Once the resources from the operational mission came to an end, ESA established a number of joint activities with the Rosetta instrument teams to allow them to continue to work on enhancing their archive content.  The updates planned were focused on key aspects of an instrument’s calibration or the production of higher level data / information, and are therefore very specific to each instrument’s needs.

 

This presentation will highlight just a few of the activities within the archive enhancement to give a flavour of the updates that have already been completed and those that are expected to be delivered in the coming months.

 

Almost all instrument teams have now provided a Science User Guide for their data.  Most teams also updated calibrations for their data, and some produced higher level processed data and derived products.

 

For example, the OSIRIS team delivered data with improved calibrations, as well as straylight corrected, I/F corrected, and three-dimensional georeferenced products.  These are all already available in the archive.  OSIRIS also delivered their data additionally in FITS format, and provided quicklook versions of their products to allow an end-user to more easily sift through the data and select the images they may be interested in.  Internal straylight data and boresight corrected / full frame data were delivered in mid 2020, and have also now been added to the Rosetta archive.  Outside of the officially supported activities, the OSIRIS team aim to make a final delivery of all of their data using the final and best pipeline available in summer 2021.  The aim is to have this large volume of data available in the final archive by end of 2021.

 

Similarly, the VIRTIS team are working to update both their spectral and geometrical calibrations, and will deliver mapping products to the final archive.  This work has also been extended into early 2021, with the aim to close out the final versions by summer.

 

The Rosetta Plasma Consortium (RPC) instrument suite completed several cross-calibrations that greatly improved the final data from each experiment, as well as a number of activities individual to each instrument (e.g. removal or flagging of spacecraft noise from the MAG instrument).  An illumination map of the comet has also been produced by the RPC team to help with their cross-calibration work.

 

The MIDAS team has similarly completed cross-calibrations and produced a dust particle catalog from the comet coma.

 

The GIADA team has produced and delivered higher level products in the form of dust environment maps, with omnidirectional plus time products.

 

The ALICE, RPC-IES and MIRO instruments on Rosetta are funded by NASA, and limited enhanced archiving activites were also undertaken for these.  Data are from these activities are all already released, but a few final small updates to a few products are expected early this year.

 

The COSIMA team has delivered a ground-based catalog of spectra for comparison to help calibrate and understand their in-flight data.  These are expected to be released in 2021.

 

A separate activity has also been established to produce and deliver data set(s) containing supporting ground-based observations of the comet.  These data were taken simultaneously with Rosetta operations and could provide some important contextual information that will be of considerable value to the end user community.  Final versions of these products were delivered in mid-2020.  There is still some work needed to have these ready for a full ingestion, but the aim is to have these available in the archive this year.

 

The Rosetta ESA archiving team has also now released calibrated data sets for the NAVCAM instrument, archived all of Rosetta’s radiation monitor data, and will be working with colleagues at PDS to include the latest shape models from the comet into the final Rosetta archive later this year.  

 

Final PSA Updates: In 2020, the Rosetta ESA archiving team also worked on providing a centralized solution to the problem of geometry on the comet for implementation within the final Rosetta data holdings.  The latest version of the PSA includes a number of features to help exploit the Rosetta data with this in mind, including a 3D orbital view and a consistent set of queriable geometry data.  These will be outlined in the presentation. 

 

References: [1] Besse, S. et al., (2018) Planetary and Space Science v150, 131-140; [2] Barthelemy, M. et al.,  (2018) Planetary and Space Science v150, 91-103.