The NASA Space Science Data Center (NSSDC) supports several on-line indices and database systems, including requests for data from the IUE archive and from the Astronomical Data Center (ADC), through its On-Line Data and Information Service NODIS. Access is via telnet to nssdca.gsfc.nasa.gov (128.183.36.23) or NSI/DECnet to node NSSDCA (15548), login as nodis. The user will be asked to register and then be presented with a self-explanatory menu which e.g. allows to browse the list of available astronomical catalogs.
The NSSDC has developed an automated data retrieval request service utilizing the ``NSSDC Data Archive and Distribution Service'' (NDADS). The data held by NSSDC have been written to optical disks which are jukebox-accessed. The NDADS ``Automated Retrieval Mail System'' (ARMS) permits researchers to rapidly retrieve selections from the current NDADS holdings. Requests are submitted via electronic mail, and the data may be retrieved via anonymous FTP or NSI-DECNet copy. It is also possible to have the data sent directly to the requester's computer. For more information on ARMS, send an empty e-mail message to archives@ndadsa.gsfc.nasa.gov or NDADSA::ARCHIVES with the words SEND INFORMATION in the subject line.
NODIS also provides access to NASA's ``Master Catalog'' (NMC) which contains information about spacecraft, their instruments, and the data sets therefrom. By summer 1993 data on 4600 orbiting spacecraft and some 60 prelaunch spacecraft were available.
The NSSDC issues a newsletter (on paper) 3-4 times per year which informs about new data sets available from there (including CD-ROMs), mainly from space missions, and including planetary or geophysical data. To subscribe to ``NSSDC News'', send e-mail to NCF::REQUEST and say so. An electronic newsletter of the NSSDC-ADC is also issued and can be subscribed to by sending e-mail to listserv@hypatia.gsfc.nasa.gov with one line in the body of the message: SUBSCRIBE ADCNEWS <your_name>.