Data Moving to NSSDC Nearline Permanent Archive

By Barbara Rowland and Joe King

Over most of its life, NSSDC has accumulated a large number of digital media (tapes, CD's, etc.) and other media (mainly film) holding scientific data taken from over 370 spacecraft in geocentric and heliocentric orbits. While various technologies and interfaces have been and are being used to provide network-based electronic accessibility to these data, the permanent archive copies of the data have until recently been held only offline as media volumes on shelves.

With the initiation of DIOnAS (Data Ingest and Online Access System) and related software about two years ago, NSSDC started moving data files, bundled with supporting metadata into Archive Information Packages (AIP) compatible with CCSDS/ISO Open Archive Information System archive reference model, into its new permanent archive that used a DLT (Digital Linear Tape) jukebox attached to a Sun Enterprise 3000 computer. The December, 2000, issue of the NSSDC News has a series of articles on this new environment.

Since that time, NSSDC has completed moving all its space physics data, plus data from the InfraRed Astronomy Satellite (IRAS), from the old NSSDC Data Archive and Dissemination System (NDADS). NDADS was intended primarily for dissemination, and was a pair of 12"-WORM optical jukeboxes in a VMS environment.

While moving data from NDADS to the DLT jukebox through DIOnAS, NSSDC was also ingesting newly NSSDC-inflowing data through DIOnAS to DLT. At this point, DIOnAS has written somewhat over one terabyte of data to DLT, from the (sequenced by byte counts) ISIS, DE, IMAGE, IRAS, SAMPEX, Voyager, IMP, ISEE, Wind, Ulysses, Pioneer, and San Marco spacecraft.