A few years ago, NSSDC created the first heliospheric CD-ROM with accompanying software. This disk held for each of the spacecraft identified below (except Ulysses) hourly-resolution, annual ASCII files of merged magnetic field, plasma, and spacecraft position data. All field vector data were transformed to common (RTN) coordinates, and all position data were likewise transformed to a common (HGI) system. Some higher resolution Interplanetary Monitoring Platform (IMP) and International Sun-Earth Explorer (ISEE) data were also included.
NSSDC has just issued a new heliospheric CD-ROM that updates and extends the hourly data of the earlier CD-ROM. More than 35 spacecraft-years were added, bringing the total available to about 140 spacecraft-years.
Spacecraft and their time spans are in the following table:
SPACECRAFT MAGNETIC FLD PLASMA Helios 1 74/12-81/06 74/12-80/12 Helios 2 76/01-80/03 76/01-80/03 OMNI 63/12-95/12 63/12-96/03 Pioneer 10 72/03-75/11 72/04-95/09 Pioneer 11 73/04-92/08 73/04-92/05 Pioneer Venus 78/12-88/08 78/12-92/10 Ulysses 90/10-95/09 90/11-95/06 Voyager 1 77/09-89/12 77/09-80/11 Voyager 2 77/09-89/08 77/09-95/11
In this table "OMNI" refers to NSSDC's multispacecraft near-Earth compilation, dominated for many years by IMP 8. NSSDC has also made these files ANONYMOUS/FTP-accessible from "MERGED" subdirectories under each spacecraft subdirectory in the Coordinated Heliospheric Observations (COHO) directory on nssdca.gsfc.nasa.gov.
An updated version of MS-DOS software for data retrieval and visualization was provided for both the new CD and FTP-transferred files. The FTP address on nssdc.gsfc.nasa.gov for this software is pub/cdrom/software/dos, filename helios_n.exe. NSSDC is planning in the future to recreate the software for at least Windows-95 and Windows-NT environments.
These data are also the input files for NSSDC's WWW-accessible COHOWeb and OMNIWeb, which have uniform sets of parameters for all spacecraft. This new heliospheric CD is not being mass-replicated as was the first one since an increasing fraction of potential users have WWW and/or FTP electronic access to the data. Copies of the CD-ROM may be ordered from NSSDC's Coordinated Request and User Support Office (CRUSO) at email@example.com.
Erin D. Gardner, firstname.lastname@example.org, (301) 286-0163
Hughes STX, Code 633, NASA Goddard Space Flight Center
Greenbelt, MD 20771, U.S.A.