Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/jplnews/1299.ZIP/1299.PR

Text File | 1993-05-03 | 4KB | 72 lines

PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE [phone]

FOR IMMEDIATE RELEASE
    NASA's Jet Propulsion Laboratory is storing scientific data
from its past solar system explorations on compact disks and
making the information available to researchers worldwide.
    The JPL analysts also are looking at the data closely to see
what is there that may have been missed earlier. Mike Martin, who
has led the development of the compact disk effort, said a search
through Viking mission data revealed for the first time the
highest resolution image of Mars' giant mountain, Olympus Mons.
    JPL has gathered data on all of its planetary missions and
to date more than 150 billion bytes (150 gigabytes) have been
processed and made available to researchers.
    The data also are to be made available to the general public
through the National Space Science Data Center at Greenbelt, Md.
    Collected into books, the amount already put onto CD-ROMs
(Compact Disk-Read Only Memory), would make a library of nearly
200,000 volumes.
    Dr. J. Thomas Renfrow, manager of JPL's Planetary Data
System (PDS), said just saving the data is not enough. Data, like
museum artifacts, must be "curated" -- labeled and stored in a
way that it can be accessed. Since 1986, the PDS has been
collecting and curating the data from JPL's planetary
spacecraft.
    PDS, a cooperative effort among JPL and sixteenuniversities, has a central computer at JPL containing a catalog
through which scientists, engineers, students and teachers, can
pinpoint the location of specific data.
    About 15 percent of JPL's planetary data are now available
through the catalog.
    Preserving the data has been a challenge for JPL's experts.
In 1983, engineers found that deteriorating magnetic tapes
threatened valuable data from the Viking spacecraft which landed
on Mars and from the Mariner spacecraft which explored Venus and
Mercury.
    In a project costing nearly half a million dollars, the data
was copied from 12,500 old tapes onto 1,200 newer tapes with much
greater capacity. Two additional copies of the archive were
produced and distributed to the U.S. Geological Survey at
Flagstaff, Ariz., and to the National Space Science Data Center,
to support requests for data from scientists.
    Then, starting last year, JPL began retrieving the data
contained on 135,000 tapes which had been stored in a federal
warehouse. Using newer technology, those tapes will be copied to
higher density media, thereby reducing the number of tapes.
    PDS has pioneered methods to store science data on CD-
ROMs, similar to the compact disks in home stereos. Each disk
can hold 680 megabytes, more than five full magnetic tapes. The
cost of producing a master disk is about $1,000, but replicas can
be made for only $2 each. In comparison, copying a tape for
distribution to a scientist costs about $50.
    The PDS' first major CD-ROM archive, "Voyagers to the Outer

Planets," contains nearly all the close-up images taken by the
Voyager spacecraft of Jupiter, Saturn and Uranus (16,000 images
representing about 15 gigabytes of data). More than 500 copies of
the disk set are currently being distributed to researchers.
    Martin said disk storage not only solves the distribution
problem because of the low cost of replicas, but also it solves
the larger problem of maintaining large tape archives. The disks
need no maintenance and are expected to last 100 years.
    He said the PDS has plans to convert the major planetary
data sets to CD-ROM format within five years.
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