The GRaND migration project: State-of-the-art archive and tools for space science

Abstract:

The NASA Dawn mission spent 11 years in flight, acquiring data during cruise through interplanetary space, observing Mars during a brief flyby, and measuring the elemental composition of (4) Vesta and (1) Ceres, the most massive bodies in the main asteroid belt [e.g. 1,2]. Chemical information was acquired by Dawn’s Gamma Ray and Neutron Detector (GRaND), which measured radiation produced by galactic cosmic ray (GCR) interactions with the outermost layers of the planetary targets. GRaND also detected GCRs, solar energetic particles (SEPs), solar-flare X-rays and gamma-ray bursts (GRBs). Bursts of energetic electrons detected by GRaND while Dawn was in orbit around Ceres may have resulted from fast-Fermi acceleration of electrons at a bow shock formed by a transient atmosphere [3]. Data acquired by GRaND can be used for future studies on how solar energetic particles propagate through the heliosphere, important for both for science and understanding how space weather could impact upcoming planetary missions. Thus, the data acquired by GRaND crosses the boundaries of several disciplines within space science.

The GRaND data were originally archived at the NASA Planetary Data System (PDS) Small Bodies Node (SBN) in the now obsolete PDS3 standard. To bring the archive up to date, we have migrated the data to PDS4. A key feature of PDS4 is the use of the open-standard, eXtensible Markup Language (XML). XML provides more flexible and descriptive labeling of data files, allowing advances in software and database capabilities to be leveraged. The archive uses the nuclear spectroscopy (NucSpec) discipline dictionary developed by the SBN with input from the planetary community. NucSpec associates data with instrument settings and parameters, enabling efficient identification of records for analysis. In addition, metadata is provided to identify SEPs and other phenomena of interest to the space and astrophysics communities. Software tools were developed for easy access and processing of raw data for scientific analyses (dawn-grand-tools to be archived at NASA's GitHub repository). The new PDS4 archive and tools are described, and science use cases are presented.

[1] Prettyman et al. (2012) DOI:10.1126/science.1225354. [2] Prettyman et al. (2017) DOI:10.1126/science.aah6765. [3] Russell et al. (2016) DOI:10.1126/science.aaf4219.