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1993-05-03
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PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
FOR IMMEDIATE RELEASE
Earth scientists, inundated by volumes of data from space
satellites, will need a whole new strategy to process the
additional one-trillion bits per day expected from NASA's Earth
Observing System (Eos) in the 1990s, two NASA scientists said.
Ralph Kahn of the Jet Propulsion Laboratory in Pasadena,
Calif., and Henning Leidecker of Goddard Space Flight Center in
Greenbelt, Md., have laid out a strategy for answering the Eos
data and information challenge.
To illustrate the problem, Kahn and Leidecker said it would
take 10,000 Washington, D.C. telephone books (white pages) to
match the amount of data from one Eos day.
Put another way, the Eos archive will accumulate as much
data about every few weeks as is currently stored in the 19
million bound books in the Library of Congress.
The two scientists outlined their program in a detailed
paper, entitled "The Crush of New Data Knocking at Our Door,"
published in the winter edition of Renewable Resources Journal.
The Eos project includes polar-orbiting, instrument-laden
platforms that will sense ocean-atmosphere interactions, geologic
processes, agricultural use, ice distribution, forestry and
weather patterns among other studies for a wide range of
geophysical disciplines.
About 30 instruments are currently planned for the Eos
system and some will have average data rates of 5 million bits to
20 million bits per second. The primary conduit of Eos
information to Earth is currently through the Tracking and Data
Relay Satellite System (TDRSS) which sets a limit on the amount
of data the Eos program can receive on Earth.
Still, it will take less than a week for the Eos data sets
to exceed the sum of all present Earth science data bases.
As a result of the wealth of information EOS will make
available, the project will include a Data and Information System
which is "unprecedented in its scope," the scientists said
Fortunately, they said, storage technology continues to
develop rapidly and there are hopes that new developments will
reduce the size of the Eos data storage problem to manageable
proportions.
Some access to the data bases will be through electronic
computer networks. Data sets one-million bits in size easily
move through the networks now in place, the scientists said.
"While the operational tasks posed by Eos are challenging,
they do not seem impossible to perform in the Eos time frame (by
the mid-1990s)," Kahn and Leidecker said.
Performing the science analyses task with all the Eos data
may prove even more challenging. Three-dimensional display of
data objects is envisioned in the new data analysis environment
using technology which in some aspects has existed since the
late 1960s, but which has not yet been put to use for thesepurposes.
The scientists said one aspect of the display would include
matching the speed of the display to human perception rates
because processes that are several times faster or several times
slower are not perceived.
They said an example is time-lapse photography which has
opened to human perceptions a world of slow processes such as the
blooming of a flower. Also, high-speed photography has shown how
the wings of birds actually function in flight.
These technologies are technically demanding and expensive,
they said, and the display speed is usually fixed in advance so
it cannot conveniently be varied over a wide range.
But a combination of computer and video technologies now in
development promises relatively inexpensive displays capable of a
wide degree of time-scaling.
"We can expect these will be as productive of discoveries in
the 'time domain' as microscopes and telescopes have been in the
'space domain'," they said.
One additional problem in the Eos data stream planning,
they said, is policy, which includes getting the data properly
archived and made accessible to users across a wide spectrum of
disciplines. That means a common lexicon of terms and keywords,
and a directory that any researcher interested in Eos data can
access with relative ease.
"A user should be able to search many databases without
having to find a new abbreviation for 'latitude' for example, in
order to access each one," they said. The computer language
must be as recognizable to a forestry scientist as to a
geologist, and to an agronomist as to an oceanographer.
Work on the paper was performed by Ralph Kahn, a staff
scientist at the Jet Propulsion Laboratory, California Institute
of Technology, under contract with NASA, and by Henning
Leidecker, a materials scientist at NASA's Goddard Space Flight
Center.
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