🚀 go-pugleaf

Daily                 News
Thursday, January 21, 1993 
Two Independence Square, Washington, D.C. 
Audio service: 202/358-3014

 % 1992 Antarctic Ozone Hole is the largest ever recorded;
 % Astronomers, using STS-54 data, announce probable cause for X-ray glow;
 % Columbia & Spacelab module on schedule for late- February launch of STS-55.

* * * * * * * * * * * * * * * *

Scientists at the Goddard Space Flight Center announced Tuesday that
the 1992 Antarctic Ozone Hole was as large as any depletion measured
since 1985.  The ozone hole depleted one to two weeks earlier than in
prior winter seasons.  The Goddard team also reports that this year's
depletion covered the  largest area ever recordedPin excess of 8.9
million square miles (23 million square kilometers).  By way of
comparison, all of North America covers 9.4 million square miles (24.5
million square kilometers.)

The team also reported that the ozone depletion remained nearly two
weeks longer than has been the recent normal case.  Other late breakups
occurred during the 1987 and 1990 winters as well.  Extensive
scientific investigations during the past seven years have tied the
depletion over the Antarctic to the presence of manufactured chlorine
compounds, chiefly from chlorofluorocarbons used as refrigerants and
industrial cleaning agents.  Additional atmospheric investigations in
more recent years have also tied the eruptions of the Mt. Pinatubo
volcano in the Philippines to the ozone depletion because of sulfuric
acid droplets released during the eruption.

The Goddard team relies on two Total Ozone Measurement Sensors, one  on
the U.S. Nimbus-7 spacecraft and one on the Russian Meteor-3
spacecraft, for continuous global ozone monitoring.

* * * * * * * * * * * * * * * *

Astrophysicists at the University of Wisconsin announced this week
preliminary results of the just-completed flight of their Diffuse X-ray
Spectrometer aboard Endeavour's STS-54 mission.  The instrument had
gathered spectrographic data on the energy and wavelengths of the
diffuse X-ray illumination which pervades the sky in all directions in
an attempt to resolve the mystery of its origin.  The Wisconsin team's
announcement says they have concluded that the X-rays come from clouds
of superheated gas created, probably, by ancient supernova explosions.

For over 30 years astronomers have pondered the origin of a low-energy
X-ray background radiation which seemed to come from empty space,
including that surrounding our solar system.  One leading theory for
the source of this energy was the possibility that pockets of
interstellar gas would be superheated by supernovae and glow in X-ray
wavelengths.  The Wisconsin team reports their data support this theory
completely and cite a specific supernova remnant from 300,000 years ago
as the likely originator of the superheating episode for these X-rays.

The Wisconsin team says that explosion, also the likely source of the
pulsating star Geminga, was one source for the superheated clouds but
their data also showed the likelihood of another, far more ancient
supernova, as the probable source for different wavelength and energy
X- rays.  Wilton Sanders, principal investigator for the DXS
instrument, says that the earlier supernova likely created a bubble of
"not white hot, not blue hot, but X- ray hot" gas to which was then
added the X-ray hot bubble of the more recent supernova.  Sanders
cautioned that, though the data are excellent and fit the theory, this
is still only a preliminary analysis.

* * * * * * * * * * * * * * * *

Kennedy Space Center vehicle and payload operators report they are
still working towards a late February launch of Columbia for the German
D-2 Spacelab mission.  The KSC team is installing the Spacelab tunnel
today and working to close out orbiter mid-body and aft compartments.
The Spacelab D-2 interface verification test has been successfully
completed.

Here's the broadcast schedule for Public Affairs events on NASA Select
TV.  Note that all events and times may change without notice, and that
all times listed are Eastern.  Live indicates a program is transmitted
live.

Thursday, January 21, 1993
Live    12:00 pm NASA Today news program.
        12:15 pm Aeronautics & Space Report.
        12:30 pm Best of NASA Today - Technology 2001.
         1:00 pm Journey through the Solar System.
         1:30 pm Space Navigation.
         2:00 pm Starfinder program #4.
         2:30 pm Life in the Universe.
         3:00 pm Total Quality Management program #27 from 
                 the University of New Mexico series.
at 4:00 and 8:00 pm and 12:00 midnight the broadcast 
             schedule of the day repeats.
 

This report is filed daily at noon, Monday through Friday.  It is a
service of NASA's Office of Public Affairs.  The editor is Charles
Redmond, 202/358-3014 or CREDMOND on NASAmail.  NASA Select TV is
carried on GE Satcom F2R, transponder 13, C-Band, 72 degrees West
Longitude, transponder frequency is 3960 MegaHertz, audio subcarrier is
6.8 MHz, polarization is vertical.