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Date:         Fri, 10 Apr 1992 00:47:29 EDT
Reply-To:     S Kotsonis <ntepy@WPI.WPI.EDU>
From:         S Kotsonis <ntepy@WPI.WPI.EDU>
Subject:      NASA NEWS 09/04/92
Comments: To: Hellenic Discussion List <hellas@brownvm.brown.edu>

This is NASA Headline News for Thursday, April 9, 1992 . . .

Office of Space Flight management, following a final review of
Endeavour's flight readiness firing results, has opted to replace all
three of the space shuttle main engines with three previously-flown
engines. Irregularities were identified in the data from two of
Endeavour's three engines. Neither irregularity would have been a
safety concern had Endeavour launched. Nevertheless, in the interest of
prudence and because the work will have little impact on Endeavour's
launch processing schedule, Kennedy Space Center technicians will
replace the engines. The data analysis indicated that engine number one
had a buildup of pressure in the liquid oxygen preburner following the
auto-shutdown sequence at the conclusion of the 22-second test firing.
This condition has been seen previously in main engines when they are
shutdown in sea-level pressures.  However, the pressure buildup
requires that the preburner face plate be inspected for possible
deflections. The other irregularity was a slightly elevated frequency
in the vibrations of ball bearings in the high pressure oxidizer
turbopump on engine number two, suggesting the beginnings of bearing
wear.

The work to remove Endeavour's engines, inspect hydrogen and oxygen
feed lines and reinstall three different engines is already underway.
Shuttle flight management is expecting no more than a couple of days
impact to the launch schedule and is still anticipating a launch of
Endeavour for the STS-49 mission in the first week of May.  The formal
Flight Readiness Review is set for April 21. Shuttle management will
announce an official launch date then.

Astronomers and astrophysicists yesterday reported they have made the
first detection of high-energy gamma rays from a class of active
galaxies which exhibit similar properties to quasars. The findings,
based on data from the orbiting Compton Gamma Ray Observatory, found
three active galaxies -- MK 421, 0537-441 and 0716+714 -- were emitting
the gamma ray energy. These galaxies are members of a group called BL
Lacertae objects (named after the first one of its kind, which was
found in the Constellation Lacertae -- the Lizard). These quasar-like
objects emit prodigious amounts of radiation from radio wavelengths
through ultra-short X-rays, and now, with the Compton data, gamma rays
as well. The engine for these objects, as is the case with the quasars,
is also theorized to be a supermassive black hole.

Flight controllers at the Jet Propulsion Laboratory report that
Magellan and Galileo both continue to perform well. In its orbit about
Venus, Magellan is continuing to carry out Phase III of its planetary
radar mapping, acquiring complementary data to that it acquired two
years ago in support of the stereo mapping project. To date, some 14
percent of the planet has been covered sufficiently to be stereo-
mapped. The alignment of the Earth, Sun and Venus is approaching
superior conjunction again, and as happened before, communications
between Magellan and the Deep Space Network stations will get spottier
as Venus moves closer to the Sun. Superior conjunction occurs on June
14.

Galileo controllers report their spacecraft is now 262 million miles
from Earth and closing toward its December home-planet flyby at
slightly more than six million miles a week. The spacecraft is in a
one-week pre-cooling period and will enter its sixth cooling maneuver
next Monday, April 13.

The Lewis Research Center yesterday selected General Electric Co.,
Cincinnati, and Pratt & Whitney Aircraft, East Hartford, as contractors
for a five-year, $84 million aeropropulsion technology support
program.  The two companies will develop, build and test aircraft
propulsion systems and components to be used in those systems. This
contract is one element of the Office of Aeronautics and Space
Technology's Large Engine Technology Program, a long-term, innovative
research and technology initiative which is looking for solutions to
some of the development issues facing future generations of large,
high-thrust engines.

--
Stefanos Kotsonis
ntepy@wpi.wpi.edu
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU