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"930422.DFC" (42564 bytes) was created on 04-22-93
22-Apr-93 Daily File Collection
These files were added or updated between 21-Apr-93 at 21:00:00 {Central}
and 22-Apr-93 at 21:06:55.
=--=--=START=--=--= NASA Spacelink File Name:930422.REL
4/22/93: NASA ENGINEER RECEIVES TECHNOLOGY TRANSFER AWARD
Charles Redmond
Headquarters, Washington, D.C.
Apri
RELEASE: 93-73
A senior design engineer at NASA's Lewis Research Center, Cleveland,
was awarded the Federal Laboratory Consortium Award of Excellence in Technology
Transfer for 1993.
Richard T. Barrett, an engineer in Lewis' Structural Systems Division,
was one of 28 government employees who was awarded the plaque in ceremonies in
Pittsburgh yesterday.
The Federal Laboratory Consortium awards recognize U.S. federal
laboratory employees who have done an outstanding job of transferring
technology developed in their government laboratory to outside users such as
other government agencies or the private industry sector.
Barrett's recognition is based on his preparation of the first
comprehensive fastener design manual, created for use by design engineers in
the aerospace and construction industries. In the last 3 years, more than
5,000 copies of this document have been placed in engineering offices.
Fasteners, such as screws, nuts, and bolts, are some of the most
important features in the design of all hardware. On a typical desktop
computer there are as many as 30 fasteners that attach peripheral devices to
the computer motherboard and to the case. With proper selection of a fastener,
a technician can assemble the computer in 30 minutes. With an improper
selection, the assembly process can take as long as several hours.
Barrett's manual assists the designer in selecting the proper fastener
by providing correct configuration data on fastener sizes, types, materials,
reliability and performance.
-end-
Source:NASA Spacelink Modem:205-895-0028 Internet:192.149.89.61
=--=--=-END-=--=--=
=--=--=START=--=--= NASA Spacelink File Name:930422.SKD
Daily News/TV Sked 4/22/93
Daily News
Thursday, April 22, 1993
Two Independence Square,
Washington, D.C.
Audio Service: 202/358-3014
% STS-55 mission status;
% LeRC employee honored;
% Work as scheduled on Space Shuttle Endeavour.
Friday, at 8:30 a.m. EDT, NASA managers will hold the L-1 Countdown status
briefing for Columbia's upcoming STS-55 mission. Following the countdown
status briefing, the STS-55 pre-launch press conference will be held at 11:30
a.m. EDT. Launch for the Space Shuttle Columbia is still targeted for Saturday
at 10:52 a.m. EDT. The mission is scheduled to last 9 days with a landing at
the Kennedy Space Center.
* * * * * * * * * * * * * * * *
Richard T. Barrett, an senior design engineer at NASA's Lewis Research Center
was awarded the Federal Laboratory Consortium Award of Excellence in Technology
Transfer for 1993. The Federal Laboratory Consortium awards recognize U.S.
federal laboratory employees who have done an outstanding job of transferring
government technology to outside users, such as the private industry sector or
other government agencies.
Barrett gained recognition for his preparation of the first comprehensive
fastener design manuel. It was created for use by design engineers in the
aerospace and construction industries. The manual assists the designer in
choosing the correct fastener by providing correct configuration data on types
of fasteners, their sizes and reliability and performance.
* * * * * * * * * * * * * * * *
Technicians at the Kennedy Space Center continue to prepare the Space Shuttle
Endeavour for its upcoming flight. The Space Shuttle Endeavour's STS-57
mission is scheduled to last 7 days and carry the Spacehab-1 payload. During
this mission, crew members will retrieve the EURECA satellite.
* * * * * * * * * * * * * * * *
Here's the broadcast schedule for Public Affairs events on NASA 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, April 22, 1993
Noon NASA Today News
12:15 pm Aeronautics & Space Report
12:30 pm The Best of NASA Today
Live 1:00 pm Space Astronomy Update
2:00 pm Short Walk to Everywhere
2:30 pm "Reaching for the Stars (Replay)
3:00 pm Dr. Stone on TQM
Friday, April 23, 1993
Noon NASA Today News
12:15 pm Aeronautics & Space Report
12:30 pm Adventures in Research
1:00 pm We Deliver
1:30 pm Our Laboratories in Space
2:00 pm Space for Women
2:30 pm "Mission to Planet Earth" (Replay)
NASA TV is carried on GE Satcom F2R, transponder 13, C-Band, 72 degrees West
Longitude, transponder frequency is 3960 MHz, audio subcarrier is 6.8 MHz,
polarization is vertical.
Source:NASA Spacelink Modem:205-895-0028 Internet:192.149.89.61
=--=--=-END-=--=--=
=--=--=START=--=--= NASA Spacelink File Name:930422A.REL
4/22/93: NASA SATELLITE DATA SHAKE THEORIES ON GAMMA-RAY BURSTS
Paula Cleggett-Haleim
Headquarters, Washington, D.C. April 22, 1993
Michael Finneran
Goddard Space Flight Center, Greenbelt, Md.
Jim Sahli
Marshall Space Flight Center, Huntsville, Ala.
RELEASE: 93-72
New findings from a NASA satellite indicate that powerful gamma-ray
bursts, one of the great mysteries of astronomy, may be more energetic than
previously thought and appear to originate far beyond the Milky Way galaxy.
The new data from the Compton Gamma-Ray Observatory raise the
possibility that the bursts of high energy radiation may be caused by unknown
objects or phenomena in the universe, scientists said at a press conference
today at NASA Headquarters, Washington, D.C.
"These results eliminate some theoretical models entirely and produce
severe constraints on other possible theories" about the source of the
gamma-ray bursts, said Dr. Carl E. Fichtel of NASA's Goddard Space Flight
Center, Greenbelt, Md. He is the co-principal investigator for one of the
satellite's instruments, the Energetic Gamma Ray Experiment Telescope (EGRET).
The critical new data include observations of the highest energy
gamma-rays ever recorded in a burst.
A 2-year mapping survey by another satellite instrument, the Burst and
Transient Source Experiment (BATSE), show that the bursts are evenly
distributed in space. BATSE has seen an average of one gamma-ray burst a day
since the observatory was launched on April 5, 1991. As of March 23, 1993, 591
bursts have been recorded.
The pattern of the bursts on the sky has shown them to be distributed
like no other known objects in the Milky Way, indicating that they may
originate outside the galaxy, said Dr. Chryssa Kouveliotou, a BATSE team member
who works for Universities Space Research Association, a contractor at NASA's
Marshall Space Flight Center, Huntsville, Ala.
Super Bowl Burst
An important clue to the puzzle was obtained on Jan. 31, 1993, when
EGRET recorded a gamma-ray burst that was 10 times higher in energy than any
previously observed since the launch of Compton. The burst -- dubbed the "Super
Bowl Burst" because it was seen on Super Bowl Sunday -- was more than 100 times
brighter at its peak than the brightest steady source of gamma rays in the
Milky Way galaxy and more than 1,000 times brighter than any other known
sources outside the Milky Way.
Aside from its extreme brightness, this event is similar in most other
respects to the other bursts recorded by Compton and earlier satellites.
Because bursts this bright are relatively rare and the EGRET experiment views
only a small portion of the sky at a particular time, astronomers were
incredibly lucky to have this event occur when EGRET was pointed in that
general direction. The nature of the burst indicates that many more may be
occurring than scientists detect.
"The EGRET observation of the highest-energy gamma rays suggests they
may be emitted in a small beam, like a spotlight, to escape the source," said
Dr. Brenda Dingus, an EGRET team member who works for Universities Space
Research Association at Goddard. "However, to observe such a small beam, it
must be pointed at us. So there may be many more objects emitting gamma-ray
bursts that we do not see because their beams point elsewhere."
Both the BATSE and EGRET results undercut the two most widely accepted
models that attempted to explain gamma-ray bursts prior to Compton's launch.
One model says the bursts are energy releases from neutron stars and
are confined to the Milky Way galaxy and a region, or "halo," surrounding it.
A neutron star is the small, extremely dense remnant core ofa star that has
exploded in a supernova. Since the Earth is in the outer suburbs of the Milky
Way, more bursts should be seen toward the more densely populated center of the
galaxy than elsewhere, according to this model.
"But that hasn't turned out to be the case. Gamma-ray bursts do not
seem to cluster in a preferred region of the sky," said Kouveliotou. "These
bursts are emitted from all directions and vary greatly in intensity and time
structure."
Colliding Black Holes
Another model suggests that gamma-ray bursts emanate from the distant
reaches of the universe, possibly the result of stars exploding or neutron
stars or black holes colliding. Black holes are believed to be stars that have
collapsed to such high density that light cannot escape their resulting
super-gravity. Many of these models predict that the gamma rays are the
thermal energy from the hot, glowing body produced in these explosions or
collisions. But the gamma rays seen by EGRET from the Super Bowl Burst are not
of the thermal type.
"This begs the question -- If these collisions or explosions are not
the source of gamma-ray bursts, what are? We don't know yet," said Marshall's
Dr. Gerald Fishman, the BATSE Principal Investigator. "It is possible that some
new object or phenomenon is producing these bursts."
Fishman said the Compton data will be studied by scientists from around
the world who are seeking to unravel the puzzle of gamma-ray bursts.
"It's difficult to say exactly where this new information will lead,"
said Fishman, "but it's probably safe to assume that we'll have to rewrite the
textbook on gamma-ray bursts."
The Compton Gamma-Ray Observatory is managed by Goddard Space Flight
Center for the Office of Space Science at NASA Headquarters, Washington, D.C.
BATSE was developed by Marshall Space Flight Center. EGRET was developed by
Goddard.
Source:NASA Spacelink Modem:205-895-0028 Internet:192.149.89.61
=--=--=-END-=--=--=
=--=--=START=--=--= NASA Spacelink File Name:930422B.REL
INFORMATION IN THIS RELEASE IS EMBARGOED UNTIL 6PM TODAY
4/22/93: 1992-93 GLOBAL OZONE LEVELS LOWER THAN ANY PREVIOUS YEAR
Brian Dunbar
NASA Headquarters, Washington, D.C.
Em
Allen Kenitzer
Goddard Space Flight Center, Greenbelt, Md.
RELEASE: 93-74
In the second half of 1992, global ozone levels were 2 to 3 percent lower
than any previous year and 4 percent lower than normal, based on extensive data
analysis from NASA's Nimbus-7 satellite.
"We are seeing lower global ozone values than we've ever seen before,"
said James F. Gleason, Ph.D., an atmospheric scientist with the University
Space Research Association working at NASA's Goddard Space Flight Center,
Greenbelt, Md. "We predicted lower ozone in 1992, but nothing like the values
we actually observed."
The very lowest levels were observed in December 1992 when the global
average was approximately 280 Dobson units. By comparison, a normal December
value is about 293 Dobson units. Previously, the lowest level of 286 Dobson
units was observed in December 1987.
Ozone, a molecule made up of three atoms of oxygen, is located primarily
in the upper atmosphere, where it absorbs harmful ultraviolet radiation from
the sun. A Dobson unit is the physical thickness of the ozone layer if it were
brought to the Earth's surface (300 Dobson units equals 1/10th of an inch or 3
millimeters).
Extensive analysis of independent data from the National Oceanic and
Atmospheric Administration (NOAA-11) Solar Backscatter Ultraviolet spectrometer
(SBUV/2) and the Russian Meteor-3 Total Ozone Mapping Spectrometer (TOMS)
instrument confirm the Nimbus-7 TOMS data. Comparison of all systems with the
ground-based World Standard Dobson Instrument and the Dobson network indicates
that the satellite instrument measurements are consistent during the period.
Northern Hemisphere Mid-Latitudes
The 1992 ozone levels were especially low in the mid-latitudes of the
northern hemisphere. The December 1992 mid-latitude ozone levels were 9
percent below normal. The low mid-latitude ozone values continue into 1993.
The January 1993 ozone levels were 13-14 percent below normal. Preliminary
observations of March 1993 mid-latitude ozone show that the levels continue to
be 11 to 12 percent below normal.
Preliminary results from the Shuttle Solar Backscatter Ultraviolet (SSBUV)
instrument, flown as part of the recent ATLAS 2 mission, also observed low
springtime, northern hemisphere ozone levels in agreement with Nimbus-7 TOMS.
Only in the equatorial region were ozone values well within the range of the
previous year's data.
Scientists say they can only speculate on the cause of the 1992 low ozone
values. While the exact cause is unknown, the low ozone may be related to the
continuing presence of particles produced in the upper atmosphere following the
eruption of Mount Pinatubo in the Philippines in June 1991. The results of
this ozone data analysis will be published in Science magazine.
The Nimbus-7/TOMS has measured ozone levels since November 1978 and
continues to be the primary monitor of global ozone levels. The NASA TOMS
instrument on the Russian Meteor-3 satellite was launched in August 1991. The
NOAA-11 SBUV/2 has measured ozone since January 1989. The SSBUV has flown
annually on the Space Shuttle since 1989.
The TOMS instruments, the Nimbus-7 satellite and the SSBUV project are
managed by the Goddard Space Flight Center for NASA's Office of Mission to
Planet Earth, Washington, D.C.
Mission to Planet Earth is NASA's long term, coordinated research effort
to study the Earth as a global environmental system. It is comprised of
satellites such as Nimbus-7 and UARS, Space Shuttle missions such as this
month's flight of ATLAS-2 and airborne and ground-based studies.
The NOAA-11 SBUV/2 instrument was launched in December 1988 and is one of
a sequence of operational ozone measuring instruments on board the NOAA
operational spacecraft series. The spacecraft and instruments are managed by
NOAA/National Environmen Service. The data processing and evaluation is a
cooperative NOAA-NASA effort.
Source:NASA Spacelink Modem:205-895-0028 Internet:192.149.89.61
=--=--=-END-=--=--=
=--=--=START=--=--= NASA Spacelink File Name:930422C.REL
4/22/93: NASA F-15 MAKES FIRST ENGINE-CONTROLLED TOUCHDOWN
Drucella Andersen
Headquarters, Washington, D.C.
Don Nolan
Dryden Flight Research Facility, Edwards, Calif.
RELEASE: 93-75
With its flight controls deliberately locked, a NASA F-15 research
aircraft yesterday touchdown using only engine power for control at NASA's
Ames-Dryden Flight Research Facility, Edwards, Calif.
The milestone flight was part of a NASA project to develop a computer-
assisted engine control system that lets a plane land safely with only engine
power if its normal control surfaces such as elevators, rudders or ailerons are
disabled.
"After several incidents where hydraulic failures caused aircraft to
lose part or all of their flight controls, including the crash of a United
Airlines DC-10 at Sioux City, Iowa in 1989, we started work on developing this
automatic engines- only control system. Within a few months, I was pretty sure
we could make it work, but I wasn't sure we would get a chance to fly it," said
Bill Burcham, Chief of Dryden's Propulsion and Performance Branch.
"Now that the technology is proven, I hope to see it incorporated into
future aircraft designs," Burcham added. "I also hope it never has to be used."
Changes to the NASA F-15's digital flight control system include a
cockpit panel with two thumb-wheel controls, one for pitch (nose up and down)
and the other for banking (turn) commands. The system converts the pilot's
thumb-wheel inputs into engine throttle commands.
The flight control system automatically programs the engines to turn
the aircraft, climb, descend and eventually land safely by varying the speed of
the engines one at a time or together.
The first flights of the system in February 1993 tested the engine
control program as the F-15 performed pitch and bank maneuvers and did checks
of the safety features at 5000 feet (1524 meters). Later flights made
progressively lower approaches to a runway.
The landing mission, flown by NASA research pilot and former astronaut
Gordon Fullerton, was the high point of almost 2 years of studies that resulted
from incidents in which the hydraulic control systems on large aircraft failed
during flight. The pilots in those cases were left with little or no ability
to land normally using their control surfaces.
"Having the capability to control and land an aircraft without the use
of the flight control system, nor the movement of the aircraft control
surfaces, is a real breakthrough in technology for improving the safety of
future aircraft, both civil and military," said Dr. James Stewart, NASA Project
Manager.
In the initial Dryden studies, an engineer-pilot research team used
simulators to check the handling and control of a four-engine transport and the
F- 15. They "flew" the simulated plane in both the computer-assisted mode and
with manual engine control using hand throttles.
The study showed both aircraft could be controlled somewhat with manual
engine inputs during level flight and easy maneuvers, but they would be
extremely difficult to land successfully. When the control system was
optimized for engine control, simulated safe flight and landings were possible
even in air turbulence and crosswinds.
The propulsion control software on the F-15 is a research concept only.
In the future, this type of technology could be applied operationally to
multi-engine aircraft with electronic engine and flight control systems.
McDonnell Douglas Aerospace (MDA), St. Louis, is the main contractor
for the propulsion-only control system. MDA did engineering analyses,
integrated the software into the F-15's flight control system and supported the
test flights.
Source:NASA Spacelink Modem:205-895-0028 Internet:192.149.89.61
=--=--=-END-=--=--=
=--=--=START=--=--= NASA Spacelink File Name:4_3_5_3.TXT
4/22/93: NASA F-15 MAKES FIRST ENGINE-CONTROLLED TOUCHDOWN
Drucella Andersen
Headquarters, Washington, D.C.
Don Nolan
Dryden Flight Research Facility, Edwards, Calif.
RELEASE: 93-75
With its flight controls deliberately locked, a NASA F-15 research
aircraft yesterday touchdown using only engine power for control at NASA's
Ames-Dryden Flight Research Facility, Edwards, Calif.
The milestone flight was part of a NASA project to develop a computer-
assisted engine control system that lets a plane land safely with only engine
power if its normal control surfaces such as elevators, rudders or ailerons are
disabled.
"After several incidents where hydraulic failures caused aircraft to
lose part or all of their flight controls, including the crash of a United
Airlines DC-10 at Sioux City, Iowa in 1989, we started work on developing this
automatic engines- only control system. Within a few months, I was pretty sure
we could make it work, but I wasn't sure we would get a chance to fly it," said
Bill Burcham, Chief of Dryden's Propulsion and Performance Branch.
"Now that the technology is proven, I hope to see it incorporated into
future aircraft designs," Burcham added. "I also hope it never has to be used."
Changes to the NASA F-15's digital flight control system include a
cockpit panel with two thumb-wheel controls, one for pitch (nose up and down)
and the other for banking (turn) commands. The system converts the pilot's
thumb-wheel inputs into engine throttle commands.
The flight control system automatically programs the engines to turn
the aircraft, climb, descend and eventually land safely by varying the speed of
the engines one at a time or together.
The first flights of the system in February 1993 tested the engine
control program as the F-15 performed pitch and bank maneuvers and did checks
of the safety features at 5000 feet (1524 meters). Later flights made
progressively lower approaches to a runway.
The landing mission, flown by NASA research pilot and former astronaut
Gordon Fullerton, was the high point of almost 2 years of studies that resulted
from incidents in which the hydraulic control systems on large aircraft failed
during flight. The pilots in those cases were left with little or no ability
to land normally using their control surfaces.
"Having the capability to control and land an aircraft without the use
of the flight control system, nor the movement of the aircraft control
surfaces, is a real breakthrough in technology for improving the safety of
future aircraft, both civil and military," said Dr. James Stewart, NASA Project
Manager.
In the initial Dryden studies, an engineer-pilot research team used
simulators to check the handling and control of a four-engine transport and the
F- 15. They "flew" the simulated plane in both the computer-assisted mode and
with manual engine control using hand throttles.
The study showed both aircraft could be controlled somewhat with manual
engine inputs during level flight and easy maneuvers, but they would be
extremely difficult to land successfully. When the control system was
optimized for engine control, simulated safe flight and landings were possible
even in air turbulence and crosswinds.
The propulsion control software on the F-15 is a research concept only.
In the future, this type of technology could be applied operationally to
multi-engine aircraft with electronic engine and flight control systems.
McDonnell Douglas Aerospace (MDA), St. Louis, is the main contractor
for the propulsion-only control system. MDA did engineering analyses,
integrated the software into the F-15's flight control system and supported the
test flights.
Source:NASA Spacelink Modem:205-895-0028 Internet:192.149.89.61
=--=--=-END-=--=--=
=--=--=START=--=--= NASA Spacelink File Name:6_2_18_5.TXT
NOTE: This file is too large {30591 bytes} for inclusion in this collection.
The first line of the file:
- Current Two-Line Element Sets #179 -
Source:NASA Spacelink Modem:205-895-0028 Internet:192.149.89.61
=--=--=-END-=--=--=
=--=--=START=--=--= NASA Spacelink File Name:6_2_2_43_11.TXT
STS-55 LAUNCH WEATHER FORECAST
L-2 DAY WEATHER FORECAST FOR STS-55
George H. Diller
NASA Kennedy Space Center
At the opening of the launch window at 10:52 a.m. on Saturday conditions are
forecast to be:
Clouds: 3,000-6,000 scattered stratocumulus, 25% sky coverage
Visibility: 7 or miles or greater
Wind - Pad 39A: ESE/12-18 knots
Temperature: 73 degrees
Dewpoint: 54 degrees
Humidity: 51%
Precipitation: none
Other weather concerns: slight chance of RTLS crosswind violation
slight chance of ceiling below 8,000 feet
Probability of launch weather criteria violation: 10%
tanking criteria violation: 0%
Probability of launch weather violation on Sunday: 10%
tanking violation on Sunday: 0%
Probability of launch weather violation on Monday: 10%
tanking violation on Monday: 0%
Cape Canaveral Forecast Facility
Department of the Air Force
4/22/93
Source:NASA Spacelink Modem:205-895-0028 Internet:192.149.89.61
=--=--=-END-=--=--=
=--=--=START=--=--= NASA Spacelink File Name:6_2_2_43_7.TXT
STS-55 Keplerian Elements/State Vector (Predicted)
STS-55 elements (April 24 launch)
STS-55
1 00055U 93114.67000478 .00120200 00000-0 36300-3 0 69
2 00055 28.4697 267.1108 0003812 314.2100 45.8202 15.90487610 22
Satellite: STS-55
Catalog number: 00055
Epoch time: 93114.67000478 = (24 APR 93 16:04:48.41 UTC)
Element set: JSC-006
Inclination: 28.4697 deg
RA of node: 267.1108 deg Space Shuttle Flight STS-55
Eccentricity: .0003812 Prelaunch Keplerian Elements
Arg of perigee: 314.2100 deg Launch: 24 APR 93 14:52 UTC
Mean anomaly: 45.8202 deg
Mean motion: 15.90487610 rev/day G. L. Carman
Decay rate: 1.2020e-03 rev/day~2 NASA Johnson Space Center
Epoch rev: 2
G.L.CARMAN
STS-55
FLIGHT DAY 1 STATE VECTOR (PREDICTED)
ON ORBIT OPERATIONS
(Posted 04/22/93 by Roger Simpson)
The following vector for the flight of STS-55 is provided by NASA Johnson
Space Center, Flight Design and Dynamics Division for use in ground track
plotting programs. The vector represents the predictied trajectory of
Columbia during on orbit operations, after the OMS-2 maneuver. The vector
assumes an on time launch. Questions regarding these postings may be
addressed to Roger Simpson, Mail Code DM4, L. B. J. Space Center, Houston,
Texas 77058.
Lift off Time : 1993/114/14:52:00.000
Lift off Date : 04/24/93
Vector Time (GMT) : 114/15:35:00.000
Vector Time (MET) : 000/00:43:00.000
Orbit Count : 1
Weight : 244237.0 LBS
Drag Coefficient : 2.00
Drag Area : 2750.0 SQ FT
M50 Elements Keplerian Elements
----------------------- --------------------------
X = -16316639.1 FT A = 3608.0505 NM
Y = 11463512.2 FT E = 0.000522
Z = -9082446.2 FT I (M50) = 28.21573 DEG
Xdot = -11959.988763 FT/S Wp (M50) = 258.26527 DEG
Ydot = -21597.692493 FT/S RAAN (M50) = 266.81945 DEG
Zdot = -5764.287807 FT/S / N (True) = 342.98133 DEG
Anomalies \ M (Mean) = 342.99882 DEG
Ha = 162.4037 NM
Hp = 160.0044 NM
Mean of 1950 (M50) : Inertial, right-handed Cartesian system whose
Coordinate System origin is the center of the earth. The epoch
is the beginning of the Besselian year 1950.
X axis: Mean vernal equinox of epoch
Z axis: Earth's mean rotational axis of epoch
Y axis: Completes right-hand system
A: Semi-major axis
E: Eccentricity N: True anomaly
I: Inclination M: Mean anomaly
Wp: Argument of perigee Ha: Height of apogee
RAAN: Right ascension of ascending node Hp: Height of perigee
Source:NASA Spacelink Modem:205-895-0028 Internet:192.149.89.61
=--=--=-END-=--=--=
=--=--=START=--=--= NASA Spacelink File Name:6_6_9_4_13.TXT
UARS APRIL STATUS REPORT 4/09/93
Upper Atmosphere Research Satellite -- UARS, launched September 12, 1992,
surpassed its 18-month mission success criteria mark. More than 100 scientists
participated in a UARS workshop in Virginia Beach, Va., last month,
commemorating this occasion. More than 55 studies were presented. The
scientific focus of the workshop was high latitude processes affecting ozone in
the stratosphere and mesophere although one session highlighted higher altitude
phenomena and wind measurements. Many of the talks illustrated new
understanding of the development and distributions of important gaseous species
impacting ozone, and a newly perceived role of dynamics and transport from high
altitudes in the formation and maintenance of the Antarctic "ozone hole."
Source:NASA Spacelink Modem:205-895-0028 Internet:192.149.89.61
=--=--=-END-=--=--=
=--=--=START=--=--= NASA Spacelink File Name:6_7_11_12.TXT
COBE APRIL STATUS REPORT 4/09/93
Cosmic Background Explorer -- COBE continues to acquire all science and
engineering data without any major problems or operational errors. The COBE
Operations team is still attempting to firm up contingency plans in the event
of a gyro failure during the upcoming eclipse season, which occurs from May
through July.
Source:NASA Spacelink Modem:205-895-0028 Internet:192.149.89.61
=--=--=-END-=--=--=
=--=--=START=--=--= NASA Spacelink File Name:6_7_2_10_12.TXT
HST APRIL STATUS REPORT 4/09/93
Hubble Space Telescope -- On Wednesday, March 24, the HST spacecraft entered
Software Sun Point Safe Mode. The preliminary indication was that the solar
array electronics had sensed an erroneous position for a solar array and
transmitted this information to the onboard computer, which in turn responded
by safing the spacecraft systems. This initial level of safing suspends
science operations but retains all vehicle control through the operations
flight computer (DF-224). Initial analysis of the telemetry indicated that the
safing had been caused by a miscompare between the actual position of the solar
arrays and the position indicated by the Solar Array Drive Electronics (SADE)
resolver. The most likely cause is believed to be either a failure in the DC
power supply or the resolver electronics. The SADE are fully redundant and
operations have been switched to the correctly operating side two. Evaluation
and analysis is continuing and science operations have been resumed. The
number of observations may be reduced by about 20 percent for the next several
weeks until flight software safing modes can be modified. Once this is
accomplished, normal science operations can resume. In the event of a
subsequent failure of side two (SADE 2), science observations could still
continue by factoring power requirements into the constraints during the
planning and scheduling of the observations.
Source:NASA Spacelink Modem:205-895-0028 Internet:192.149.89.61
=--=--=-END-=--=--=
=--=--=START=--=--= NASA Spacelink File Name:6_7_5_14.TXT
4/22/93: NASA SATELLITE DATA SHAKE THEORIES ON GAMMA-RAY BURSTS
Paula Cleggett-Haleim
Headquarters, Washington, D.C. April 22, 1993
Michael Finneran
Goddard Space Flight Center, Greenbelt, Md.
Jim Sahli
Marshall Space Flight Center, Huntsville, Ala.
RELEASE: 93-72
New findings from a NASA satellite indicate that powerful gamma-ray
bursts, one of the great mysteries of astronomy, may be more energetic than
previously thought and appear to originate far beyond the Milky Way galaxy.
The new data from the Compton Gamma-Ray Observatory raise the
possibility that the bursts of high energy radiation may be caused by unknown
objects or phenomena in the universe, scientists said at a press conference
today at NASA Headquarters, Washington, D.C.
"These results eliminate some theoretical models entirely and produce
severe constraints on other possible theories" about the source of the
gamma-ray bursts, said Dr. Carl E. Fichtel of NASA's Goddard Space Flight
Center, Greenbelt, Md. He is the co-principal investigator for one of the
satellite's instruments, the Energetic Gamma Ray Experiment Telescope (EGRET).
The critical new data include observations of the highest energy
gamma-rays ever recorded in a burst.
A 2-year mapping survey by another satellite instrument, the Burst and
Transient Source Experiment (BATSE), show that the bursts are evenly
distributed in space. BATSE has seen an average of one gamma-ray burst a day
since the observatory was launched on April 5, 1991. As of March 23, 1993, 591
bursts have been recorded.
The pattern of the bursts on the sky has shown them to be distributed
like no other known objects in the Milky Way, indicating that they may
originate outside the galaxy, said Dr. Chryssa Kouveliotou, a BATSE team member
who works for Universities Space Research Association, a contractor at NASA's
Marshall Space Flight Center, Huntsville, Ala.
Super Bowl Burst
An important clue to the puzzle was obtained on Jan. 31, 1993, when
EGRET recorded a gamma-ray burst that was 10 times higher in energy than any
previously observed since the launch of Compton. The burst -- dubbed the "Super
Bowl Burst" because it was seen on Super Bowl Sunday -- was more than 100 times
brighter at its peak than the brightest steady source of gamma rays in the
Milky Way galaxy and more than 1,000 times brighter than any other known
sources outside the Milky Way.
Aside from its extreme brightness, this event is similar in most other
respects to the other bursts recorded by Compton and earlier satellites.
Because bursts this bright are relatively rare and the EGRET experiment views
only a small portion of the sky at a particular time, astronomers were
incredibly lucky to have this event occur when EGRET was pointed in that
general direction. The nature of the burst indicates that many more may be
occurring than scientists detect.
"The EGRET observation of the highest-energy gamma rays suggests they
may be emitted in a small beam, like a spotlight, to escape the source," said
Dr. Brenda Dingus, an EGRET team member who works for Universities Space
Research Association at Goddard. "However, to observe such a small beam, it
must be pointed at us. So there may be many more objects emitting gamma-ray
bursts that we do not see because their beams point elsewhere."
Both the BATSE and EGRET results undercut the two most widely accepted
models that attempted to explain gamma-ray bursts prior to Compton's launch.
One model says the bursts are energy releases from neutron stars and
are confined to the Milky Way galaxy and a region, or "halo," surrounding it.
A neutron star is the small, extremely dense remnant core of a star that has
exploded in a supernova. Since the Earth is in the outer suburbs of the Milky
Way, more bursts should be seen toward the more densely populated center of the
galaxy than elsewhere, according to this model.
"But that hasn't turned out to be the case. Gamma-ray bursts do not
seem to cluster in a preferred region of the sky," said Kouveliotou. "These
bursts are emitted from all directions and vary greatly in intensity and time
structure."
Colliding Black Holes
Another model suggests that gamma-ray bursts emanate from the distant
reaches of the universe, possibly the result of stars exploding or neutron
stars or black holes colliding. Black holes are believed to be stars that have
collapsed to such high density that light cannot escape their resulting
super-gravity. Many of these models predict that the gamma rays are the
thermal energy from the hot, glowing body produced in these explosions or
collisions. But the gamma rays seen by EGRET from the Super Bowl Burst are not
of the thermal type.
"This begs the question -- If these collisions or explosions are not
the source of gamma-ray bursts, what are? We don't know yet," said Marshall's
Dr. Gerald Fishman, the BATSE Principal Investigator. "It is possible that some
new object or phenomenon is producing these bursts."
Fishman said the Compton data will be studied by scientists from around
the world who are seeking to unravel the puzzle of gamma-ray bursts.
"It's difficult to say exactly where this new information will lead,"
said Fishman, "but it's probably safe to assume that we'll have to rewrite the
textbook on gamma-ray bursts."
The Compton Gamma-Ray Observatory is managed by Goddard Space Flight
Center for the Office of Space Science at NASA Headquarters, Washington, D.C.
BATSE was developed by Marshall Space Flight Center. EGRET was developed by
Goddard.
Source:NASA Spacelink Modem:205-895-0028 Internet:192.149.89.61
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COMPTON APRIL STATUS REPORT 4/09/93
Compton Gamma-Ray Observatory -- The first delivery of public Energetic
Gamma-Ray Experiment Telescope (EGRET) data into the archive has been made.
This data comprises photon lists, exposure histories and maps from the
verification period through July 26, 1991. As of March 25, the mean orbital
altitude was 233.11 statute miles (359.06 kilometers). Planning and rehearsal
simulations for the orbit reboost operations continue. The series of daily
orbit reboost burns are planned to begin June 15 and continue for about two
weeks.
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EUVE APRIL STATUS REPORT 4/09/93
Extreme Ultraviolet Explorer -- Observations of the planet Jupiter and the
stars DELTA-CEN and HD-131156 were planned for the first week in April,
followed by a short observation of the moon. The next sky map "gap filling"
period is scheduled for April 19 through 25.
Source:NASA Spacelink Modem:205-895-0028 Internet:192.149.89.61
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SAMPEX APRIL STATUS REPORT 4/09/93
Solar Anomalous and Magnetospheric Particle Explorer -- SAMPEX acquired all
science and engineering data without any significant problems or operational
errors. The spacecraft continues to perform well while it is in continuous
sunlight.
Source:NASA Spacelink Modem:205-895-0028 Internet:192.149.89.61
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ASTRO-D APRIL STATUS REPORT 4/09/93
Astro-D -- The instruments on the Astro-D spacecraft launched in Japan on
February 20, 1993 are being activated. The two Japanese focal plane
instruments, the Gas Scintillation Imaging Spectrometers (GISs), were turned on
in mid- March. Both GIS counters have been verified as working normally.
GSFC's Solid State Imaging Spectrometer (SIS) Charge Coupled Device (CCD)
cameras also are being activated. Both camera vent valves have opened and the
cameras currently are stabilized around -81 degrees Farenheit (-63 degrees
Centigrade).
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STS-56 Hercules images
4/15/93
Several images taken by the crew of Discovery during STS-56 have been
downlinked and released for downloading.
HRC01008.GIF
An in cabin crew shot of Mike Foale on the left, and Ken Cockrell on the
right. The sun is coming in the overhead window. The cable on the bottom
right is part of the HERCULES system, connecting the Attitude Processor
to the Inertial Measurement Unit.
HRC01037.GIF
Darwin, Australia. 180mm lens, no filter, 1/500th Sec Shutter Speed.
Latitude = 12.4 degrees South, Longitude = 130.9 degrees East.
Orbit 30.
HRC01038.GIF
Aral Sea. Taken on 4-10-93 at 3:06:43 GMT, Latitude = 46.05 N,
Longitude = 59.560 E.
HRC01039.GIF
River in Himalayan Mountains, 180mm lens, no filter, 1/500th Second Shutter
Speed.
Latitude = 27.8 degrees North, Longitude = 84.2 degrees East.
Orbit 31.
HRC03030.GIF
St. Louis, Missouri at night.
Latitude = 38.6 degrees North, Longitude = 90.2 degrees West.
The image was acquired with the image intensifier at 1/60 second
shutter speed and -2/3 exposure compensation.
Orbit 33.
HRC03031.GIF
Chicago, Illinois at night.
Latitude = 41.8 degrees North, Longitude = 87.7 degrees West.
The image was acquired with the Image Intensifier at 1/60 second
shutter speed and -2/3 exposure compensation.
Orbit 33.
HRC03032.GIF
Chicago, Illinois at night.
Latitude = 41.8 degrees North, Longitude = 87.6 degrees West.
The image was acquired with the Image Intensifier at 1/60 second
shutter speed and -2/3 exposure compensation.
Orbit 33.
HRC03033.GIF
Lansing, Michigan at night.
Latitude = 42.7 degrees North, Longitude = 84.5 degrees West.
The image was acquired with the Image Intensifier
at 1/60 second shutter speed and -2/3 exposure compensation.
Orbit 33.
HRC03035.GIF
Bonn - East of Langewehe, North of Dure
Latitude = 50.8 degrees North, Longitude = 6.4 degrees East.
A smoke plume. The image was acquired with a 300mm lens without a filter. A
shutter speed of 1/500 second and -2/3 exposure compensation was used. The
ESC was in shutter priority mode.
Orbit 33.
HRC03036.GIF
Yugoslavia Coast, point on island off Peljeski Canal
Latitude = 42.9 degrees North, Longitude = 17.2 degrees East.
A target of opportunity. The camera was in shutter priority mode with a
1/500 second shutter speed and -2/3 exposure compensation. A 300mm lens
was used without a filter.
Orbit 33.
HRC03037.GIF
Limnos Island, Greece
Latitude = 39.9 degrees North, Longitude = 25.3 degrees East.
Airport can be seen on this island. The camera was in shutter
priority mode with a 1/500 second shutter speed and -2/3 exposure
compensation. A 300mm lens without a filter was used.
Orbit 33.
HRC03039.GIF
Southern Turkish coastline along the Mediterranean Sea.
Latitude = 36.2 degrees North, Longitude = 30.4 degrees East.
A 300mm lens without filter was utilized. The camera was
in shutter priorty mode with a 1/500 second shutter speed and -2/3
exposure compensation.
Orbit 33.
HRC07020.GIF
Melbourne, Victoria, Australia
Latitude = 37.86 degrees South, Longitude = 144.87 degrees East
300mm, no filter, f/8
Orbit 46.
Source:NASA Spacelink Modem:205-895-0028 Internet:192.149.89.61
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