Download Nancy Grace Roman Almost all astronomical data in the National

Baltic Astronomy,
vol. 6, 283-286,
1997.
A S T R O N O M Y ARCHIVES AT NASA'S
GODDARD
SPACE FLIGHT CENTER
Nancy Grace Roman
Code 631, NASA/Goddard
20771, U.S.A.
Space Flight Center,
Greenbelt,
Maryland
Received July 20, 1996.
Abstract.
The extensive holdings of the Goddard Space Flight
Center of the National Aeronautics and Space Administration are
described. The ways of obtaining these data are also described.
K e y words: catalogs - data archives - Solar system - Sun
Almost all astronomical data in the National Aeronautics and
Space Administration (NASA) are archived in the Space Science
Data Operations Office (SSDOO) at the Goddard Space Flight Center (GSFC). This office started as the National Space Science Data
Center (NSSDC). This center was established as a permanent archive
for all data returned by U.S. space missions and from international
missions with which the U.S. has cooperated. It also contains a limited amount of data from space missions with no U.S. involvement.
The primary archive is derived from reduced raw data. The NSSDC
contains some ground-based data and, as discussed below, is likely
to contain substantially more in the future.
About two years ago the SSDOO was divided into three entities
dealing with the archive: the Astrophysics Data Facility (ADF), the
Space Physics Data Facility (SPDF) and the NSSDC and WorldData-Center A. The ADF provides expertise in science data operations to support the data processing, access and management requirements of current and future astrophysics missions managed by
the GSFC. The ADC is part of the ADF. The ADF also supports
astronomy in the NSSDC as well as in mission specific centers.
Unauthenticated
Download Date | 8/3/17 7:05 AM
284
Ν. G.
Roman
T h e NSSDC is becoming a repository for very large sets of d a t a
resulting from ground-based surveys. These will include the scans
of the Palomar Schmidt plates, data from the Optical Gravitational
Lensing Experiment (OGLE) and, possibly, the 2-MASS survey data.
This center may obtain the high-resolution spectrograph d a t a from
the Keck telescopes. The NSSDC also archives ground-based d a t a
that strongly complements the space data. For example, the NSSDC
has the ground-based images of the fields observed by the Ultraviolet Imaging Telescope (UIT on the ASTRO shuttle missions).
T h e NSSDC contains data of general astronomical interest acquired
by DoD missions. These include the d a t a from the lunar mission
Clementine and the observations of astronomical objects routinely
observed by the DoD as calibration targets. Also available from
the NSSDC are extensive sets of X-ray and gamma-ray observations
including d a t a of the gamma ray bursts discovered by the Vela satellites.
Much of the 1.7 terabytes of data, that the NSSDC currently
holds, can be accessed through the NASA D a t a Archive and Distribution Service (NDADS), a near-line system consisting of optical platter juke-boxes. NDADS can be accessed either by e-mail to
a r c h i v e s S n d a d s . g s f c . n a s a . g o v (on the subject line, type H E L P
for further instructions) or through the World Wide Web ( W W W ) at
h t t p : / / n d a d s . gsf c . n a s a . g o v / n d a d s / a r c h i v e s -homepage. html.
W i t h either form of access, the data are staged to an anonymous F T P
directory. After a few minutes the requester is informed by e-mail
which files are available and where. Alternatively, if the user is willing to provide a password, the data can be sent directly to his or her
computer.
T h e astronomical holdings in the NSSDC archive may be discussed in three primary categories: astrophysics, planetary and solar. From the astrophysics missions all data are included, except
those from the Extreme Ultraviolet Explorer (EUVE) and the Hubble Space Telescope (HST). The EUVE data should be in the NSSDC
soon. High energy d a t a are also accessible through the High Energy
Astrophysics Science Archive Research Center (HEASARC). This
center cooperates with the Goddard Laboratory for High Energy
Astrophysics and the ADF in managing d a t a for both currently active and older missions. HEASARC provides many services to aid
using and analyzing high energy data. Thus, it is usually the best
place to start for these data. Data from manned flights such as Astro and Apollo are also included in the NSSDC archive, but d a t a
Unauthenticated
Download Date | 8/3/17 7:05 AM
NASA astronomy
archives
285
from the Kuiper airplane and from balloon or rocket flights are not
generally present. Information on NSSDC holdings not on NDADS
can be obtained at h t t p : / / n s s d c . g s f c . n a s a . g o v / n s s d c .
The most popular set of astronomical data is from the IUE with
about 100 000 observations. There have been 200 000 requests for
IUE data from the archives, often for a number of files, with continuing requests of 500 to 1000 per month. The next most popular data
sets are the ROSAT data and the ADC data. The installation of the
ADC data on its workstation with direct F T P and W W W access has
increased the access to a level comparable with that for the IUE.
The planetary archive contains several hundred thousand images. These include images of every planet except Pluto, including
pictures of the earth taken by planetary probes, several asteroids,
the Moon and other satellites. There are infrared and ultraviolet
pictures of some of the planets and radar maps for Venus. The image archive contains all of the Halley Watch observations. Besides
the images, the NSSDC contains substantial additional data. For the
asteroids these data provide such information as the albedo, period
and orbital parameters. The archives include observations of the
Zodiacal light taken from various missions and substantial amount
of data on the environment of each planet visited by a spacecraft.
Depending on the mission, these data include the magnetic field,
infrared thermal maps, data on atmospheric winds, details about
the ionosphere, radio emission, atmospheric structure derived from
spacecraft occultations, ultraviolet photometry and the derived gravity field. All the measurements made both from the surface of the
Moon and from lunar orbiters are present. The archive also contains detailed information on the spacecraft and experiments. There
is a charge for the data, except to NASA grantees and contractors,
to cover reproduction costs. However, the fee may be reduced or
waived for legitimate researchers for whom it would be a hardship.
The index of the planetary holdings can be accessed on the W W W
at h t t p : / / n s s d c . g s f c . n a s a . g o v / p l a n e t a r y .
The bulk of the solar archive is composed of images and spectra from YOHKOH and the Solar Maximum Mission (SMM). It
also contains a substantial amount of data from earlier missions,
of which Skylab may be the most interesting. Data from the Solar
and Heliospheric Observatory (SOHO) are being archived although
many of that data will be restricted to the investigators for a year.
As for the high-energy missions, the Solar Data Analysis Center
(SDAS) provides assistance in the use of the solar data. For small
Unauthenticated
Download Date | 8/3/17 7:05 AM
286
Ν. G. Roman
amounts of data, the SD AS is the appropriate contact; for large
amounts it is best to go directly to the NSSDC. One image from
this mission each day is now available on the SDAS WWW page
(http://umbra.gsfc.nasa.gov/). As in the other areas, the emphasie in the NSSDC is on data acquired by space missions but the
archive does contain a limited amount of complementary groundbased data.
Unauthenticated
Download Date | 8/3/17 7:05 AM