Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/DAILY_1/921106.DFC

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"921106.DFC" (32341 bytes) was created on 11-06-92

06-Nov-92 Daily File Collection
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4/27/90: SCIENTISTS UNVEIL SAILS THAT WILL RACE TO MARS IN 1992


        Washington D.C., April 27, 1990 -- Designs for a six-nation fleet of
gossamer solar sails that will race to Mars in the Columbus 500 Space Sail Cup
during the 1992 International Space Year were shown to the public for the first
time at the Carnegie Institution of Washington last week.

        The sails, which fly on the flow of photons from the sun, will be of
various shapes and sizes, from a small sunflower-petals shape to a rectangular
sail that is the length of three football fields.  Most will be made of
material that is thinner and ligh er than plastic food wrap.

        The sail cup race is sponsored by the Christopher Columbus 500
Quincentenary Jubilee Commission. Based on the theme of the adventure ships
Nina, Pinta and Santa Maria, the race will feature entries from the Americas
(where Columbus sailed to), Europe where he sailed from), and Asia (where
Columbus thought he was bound for).

        Designers of contending sailing ships from the United States, Canada,
Great Britain, Italy, China and the U.S.S.R. revealed the design of their
vessels at the Carnegie Institution symposium.  Development cost estimates for
each of these designs range from $3 million to more than $15 million.

        The winning designs for the "Americas", reviewed and selected late last
year by a panel at the American Institute of Aeronautics and Astronautics
(AIAA), were submitted by the Johns Hopkins University Applied Physics
Laboratory (Laurel, MD), the World Space Foundation (Pasadena, CA), the
Massachusetts Institute of Technology (Cambridge, MA), and the Canadian Space
Society (Toronto).

        "Solar sails are beautiful ships that stream across space.  The race
will not only be fun for everyone, but it will demonstrate that these vessels
are hardy enough for future interplanetary travel," said the symposium's
co-chairman, Dr. Klaus P. Heiss, an expert in space applications.

        Solar sails have long been recognized as a viable method of space
travel; the sails travel as fast between planets as craft using chemical
propulsion, and they can potentially carry heavy cargoes.  But these racing
ships will be as light as possible, we ghing no more than 500 kilograms (about
1,100 pounds).

        The race will begin around Columbus Day, 1992, when the folded sails
will be launched into high earth orbit by rocket.  While in orbit, the sails
will unfurl from their small canisters to catch the kinetic energy of light
bouncing off their surfaces fo propulsion into interplanetary space.  The trip
from the Earth, to near Moon, and onto Mars is expected to take as little as
one year or as much as five years.  Winners will be determined at different
stages: a successful deployment and unfurling, journe beyond Earth's gravity,
closest passage near the Moon or Mars within 10,000 kilometers, and the
ultimate Cup goal of reaching Mars.

        Production of the "Americas" sails is expected to be funded by a
consortium of aerospace industries that will utilize the solar sail technology
produced for future interplanetary travel.  Free launch of one Americas entry
into space has been assured, nd NASA has agreed to provide the US Team with
technical advice, tracking and telemetry services.

        "The response from such highly qualified, technically sophisticated
organizations is an indication of the significance of the project in advancing
the technological boundaries of low-cost space transport in the next century,"
says former Congressman James W. Symington, co-chair of the symposium.

        The four winning "Americas" designs are:

        The Johns Hopkins University Applied Physics Laboratory designed an
aluminized, reflective sail in the shape of a flat disc with a diameter of 560
feet and weighing 180 kilograms (about 400 pounds).  Calling it a "sunflower",
Harold Fox, APL's solar sa l project manager, said the sail would be made of
480 "petals", each four feet wide.  The space craft will carry a television
camera, antenna, solar power panels, and a command and control "bus" as well as
instruments to perform student-designed experime ts.  The sail is estimated to
cost $15 million.  Team members and affiliations include L'Garde Inc., of
California, producers of large inflatible space structures, NASA Goddard Space
Flight Center, the Naval Academy, the Space Telescope Science Institute, the
University of Maryland and Westinghouse Corporation.

        The World Space Foundation has designed a $6.5 million sail shaped like
a square, 3,000 meters large ("many times the size of the space shuttle"),
Robert Staehle, the foundation's president, told symposium participants.  A
50-foot section of the sail h s already been tested.  The sail will carry
messages from elementary students about the future they desire for the Earth
and Universe, in cooperation with the SpaceArc project, the Rochester Museum
and Science Center. The foundation's team includes McDon ell Douglas, the Jet
Propulsion Laboratory, the Radio Amateur Satellite Corporation, Utah State
University, Weber State College, and the Planetary Society, among others.

        The Massachusetts Institute of Technology has decided to build an
extremely lightweight (no more than 44 pounds), sail about the size of a city
block (1,000 square meters).  The sail, made from a thin Kevlar film, features
eight 12-foot arms that will s in slowly to help keep the arms stiff, said
Andreas H. von Flotow, assistant professor in MIT's department of aeronautics
and astronautics.  The sail will not feature any "bells and whistles" payload,
and is expected to cost about $3 million.

        The Canadian Space Society's sail is hexagonal and flat and is about
the size of three football fields.  It features a "Venetian blinds" concept -
thin strips that rotate for control.  The sail will carry instruments for
experiments with plasma waves a d magnetism - one of the main missions of the
voyage, said Steve Horvath, the society's sail project leader .

        Additionally, proposals from Italy (Aeritalia Corporation with Italian
aerospace companies and universities), the U.S.S.R. (Moscow Aviation
Institute), Great Britain (Cambridge Consultants), and China (the Chinese Space
Society) were reviewed at the sy posium.  Italy has designed a $15 million sail
that is 10,000 square meters and made of aluminum coated Mylar. Britain's entry
has 24 carbon fiber ribs and a sail made of polyester film.  The Soviet sail,
designed by a 60-member team, is also a "sunfl wer" design of 15,000 square
meters.  The Chinese proposal, designed by university students, is similar to
the MIT design but larger.

        For information on the Solar Sail Race, or any ISY program or event,
please contact Renee Twombly, Information Director, US International Space Year
Association (US-ISY), 202-863-1734.  US-ISY was established with support from
NASA to provide information on ISY events.

######



     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
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=--=--=START=--=--= NASA Spacelink File Name:921106.REL

11/6/92: REPORT DETAILS CAUSES OF TETHERED SATELLITE MALFUNCTIONS

Mark Hess
Headquarters, Washington, D.C.              November 6, 1992

Jerry Berg
Marshall Space Flight Center, Huntsville, Ala.

RELEASE:  92-196


     The report of NASA's Tethered Satellite System
Investigative Board was released today, presenting the
panel's findings on problems which prevented full deployment
of the satellite during Space Shuttle mission STS-46.

     The 47-page report examined five problems that occurred
during the deployment effort and identified causes for four
of them.  It made recommendations for actions to be taken to
prevent similar occurrences in the future.

     The board said the two snags during deployment and
retrieval -- when first releasing the satellite from the
deployer and when the satellite was at 735 feet -- were due
to slack which developed in the tether at a point where it
moves between one pulley and another -- somewhat similar to
movie film misfeeding in a projector.

      "The crew found a way to procedurally get around this
slack problem," said Board Chairman Darrell Branscome.  "In
both cases the jamming was overcome.  By itself, this problem
would not have prevented us from fully deploying the
satellite."

     NASA previously had reported on Aug. 28 that the cause
of the unplanned stops at 587 and 840 feet was a mechanical
obstruction -- a protruding bolt -- which prevented part of
the tether reel mechanism from moving across its full range
of travel.

     "We contacted the bolt when the satellite was out at 587
feet," said Branscome.  "What we learned from our ground
simulations was that in spite of the bolt obstruction, it was
possible to pull additional tether off the reel, out to 840
feet."

     According to the report, the bolt was part of a hardware
change made late in the review process and should have been
caught in the systems engineering review.

     "The board made some excellent recommendations in the
report on how to deal with things like late changes to the
hardware," said Pearson.  "We are going to look carefully at
their recommendations and apply the lessons learned from this
flight to future missions."

     No plausible scenario has been validated by post-flight
demonstration regarding difficulty in retracting one of two
umbilicals between the tethered satellite and deployer.

     Based on its findings, the board recommended several
specific hardware assessments and modifications which should
be made to other elements of the tethered system if NASA
decides to refly it.

     The board was formed on Aug. 12 by Jeremiah Pearson,
NASA Associate Administrator for Space Flight.  The six-
member board included representatives from various NASA
centers and the Italian Space Agency.

- end -


     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
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KSC SHUTTLE STATUS 11/6/92




               SPACE SHUTTLE WEEKLY STATUS SUMMARY
                    Friday, November 6, 1992



Vehicle: OV-103/Space Shuttle Discovery
Current Location: Vehicle Assembly Building, High Bay 3
Mission: STS-53 DoD   Inclination: 57 degrees
Launch timeframe: Dec. wk 1   Nominal Landing Site: KSC
Mission duration: 7 days 5 hours 54 minutes  Crew Size: 5


STS-53 IN WORK TODAY:

- Shuttle Interface Test (electrical portion)


STS-53 WORK COMPLETED:

- mating Discovery to external tank/solid rocket booster stack


STS-53 WORK SCHEDULED NEXT WEEK:

- rollout to Pad 39-A on Sunday at 8 a.m.
- anticipated hard down at Pad 39-A at 2:45 p.m. Sunday
- auxiliary power unit hot fire early Monday morning
- begin Inertial Measurement Unit calibration on Monday
- main engine Flight Readiness Test on Tuesday
- helium signature leak test on Wednesday
- TCDT on Thursday and Friday




Vehicle: OV-105/Orbiter Endeavour
Location: OPF Bay 1
Primary Payload: TDRS-F/IUS-13 + Diffuse X-Ray Spectrometer (DXS)
Mission: STS-54                    Inclination: 28.45 degrees
Launch Timeframe: January Wk 2     Nominal Landing Site: KSC
Mission Duration: 6 days           Crew Size: 5


STS-54 IN WORK:

- drag chute door installation
- bulb seal repair
- midbody closeouts
- heat shield installation
- torque readjustment of vertical stablilizer bolts
- auxiliary power unit leak and functional checks
- tile water proofing



STS-54 WORK SCHEDULED:

- Crew Equipment Interface Test (CEIT) on Saturday
- ammonia boiler servicing on Sunday
- waste containment system checkout and functional test
- payload airborne support equipment Interface Verification Test
- changeout of reaction control system (L3A) thruster bellows
- begin payload bay cleaning
- move TDRS/IUS payload to Pad 39-B on Monday
- install DXS payload in payload bay on Tuesday



STS-54 WORK COMPLETED:

- installation of TDRS/IUS into payload canister in VPF
- remove and replace orbiter window #6
- changeout two reaction control system thrusters (L3A and L5D)
- OMS/RCS flight control system checkout
- OMS pod redundancy checks
- auxiliary power unit water servicing
- auxiliary power unit leak and functional checks
- potable water servicing
- waste containment system installation
- star tracker door functional test



Vehicle: OV-102/Orbiter Columbia
Current location: OPF Bay 2
Mission: STS-55/Spacelab-D2         Inclination: 28.45 degrees
Launch timeframe: February, wk 4    Nominal Landing Site: KSC
Mission Duration: 8 days 22 hours   Crew size: 7


STS-55 IN WORK:

- post flight orbiter inspections
- main engine inspections
- window inspections and polishing
- clean and inspect star tracker
- removal of USMP payload from payload bay
- Ku Band antenna testing
- Spacelab D-2 Mission Sequence Test in the O&C building
- auxiliary power unit lube oil deservicing



STS-55 WORK SCHEDULED:

- hypergolic deservicing
- forward reaction control system removal
- remove main engine heat shields
- remove waste containment system
- remove wheels and tires



STS-55 WORK COMPLETED:

- orbiter initial post flight safing
- orbiter jack and level
- establish orbiter access
- attach payload bay door strongback
- open payload bay doors
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
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11/6/92: DON'T FORFEIT SATELLITE RESCUE ABILITY   COVERT GROUP REPORTS

Mark Hess
Headquarters, Washington, D.C.                   November 6, 1992

RELEASE:  92-197


        A task group, looking into issues concerning future satellite rescue
and repair, says NASA should continue to perform such missions, but only when
they "produce genuine benefits to U.S. interests in view of the inherent risks
to the Shuttle and its crew."

        "The unique ability to accomplish satellite rescue and repair should
not be forfeited," said task force Chairman Dr. Eugene E. Covert. "But these
missions pose inherent risks to the Shuttle and should be undertaken only when
the benefits outweigh the risks." Covert added the authority to employ this
capability should rest solely with the NASA Administrator.

        The NASA Advisory Council Group Task Force was established at the
direction of NASA Administrator Daniel Goldin. Chairman Covert is a professor
of Aeronautics and Astronautics at Massachusetts Institute Of Technology. Vice
Chairman was former astronaut Lt. Gen. Thomas Stafford, USAF (ret).

        The charter of the group was to recommend "a policy outlining the
criteria, the design standards and the pricing model to guide NASA in assessing
the responsibilities for government and non-government satellite rescue and
repair missions."

Conclusions and Recommendations

        While pointing out that opportunities for performing unanticipated
satellite rescue or repair missions in the future are likely to be rare, the
report says the unique ability to accomplish such missions should not be
forfeited.

        "We estimated that only 1 percent of the total satellites to be
launched in the next few years will be candidates for rescue and repair," said
Covert.

        And while the trend for scientific satellites is for smaller satellites
that do not require on-orbit maintenance, the group did say the Shuttle should
continue to support those science payloads designed to be serviced, such as the
Hubble Space Telescope.

"Flexible" Approach to Pricing

        The report notes that if NASA charged customers the full cost of a
Shuttle mission, the economic benefit to the manufacturer, the owner or the
insurer "would be greatly diminished."

        The report urges NASA to keep its satellite rescue pricing policy broad
enough to accommodate U.S. government agencies and commercial enterprises as
well as international government and commercial clients.  Covert said the group
recommends a pricing approach that would vary depending upon the customer for
the mission.

        The task force recommends that non-NASA U.S. government customers pay
marginal costs which NASA defines as the cost of adding or deleting one mission
from the manifest.

        Reimbursable customers (commercial and international) should pay the
marginal cost for the mission as well as any costs up front which are unique to
that mission.

        "In addition to the marginal and unique costs, we recommend that if the
mission is a success, NASA should receive a negotiated portion of the revenues
until the full cost of the rescue is paid," Covert said.  The government should
not charge customers for Shuttle replacement, NASA facilities or facilities
amortization costs.

        If the rescue provides significant benefit to NASA or the U.S.
government, Covert said the task force recommended consideration be given to
sharing costs with the customer.

Safety Remains Top Priority

        The task force said NASA should continue to ensure that safety
requirements are met for all satellite rescue and repair missions.

        "We note in the report the Intelsat rescue mission did not have a
mission manager," Covert said. "We recommend a mission manager be named as soon
as NASA has accepted a mission, and this person should be responsible for all
aspects of preflight mission execution."

        The report also recommends added emphasis on training and the upgrade
of EVA (extravehicular activity) including use of state of the art EVA tools
and training methods.

        It also calls for the maximum use of individuals with previous
experience, both internal and external to NASA, to help ensure mission safety
and success.

Should Stress Risks

        Covert said one of the most important findings that came out of the
study was the risks of performing these types of missions.  Noting that rescue
missions on land or at sea are not always successful, the committee recommended
NASA remind the public of the risks associated with rescue missions.

        "There may be times in the future when NASA is not successful in
rescuing and repairing a satellite.  That does not mean the total, overall
Shuttle flight was a failure," he said.

        Covert said the extensive planning and training that must be done to
prepare for and carry out a complex mission such as a satellite rescue and
repair can possibly provide valuable information that will benefit space
operations in the future.

        "But the most valuable experience and information is gained from
disciplined execution of carefully planned experiments," he said.
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
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=--=--=START=--=--= NASA Spacelink File Name:921106B.REL

11/6/92: SCOUT LAUNCH RESCHEDULED FOR SUNDAY NOVEMBER 8

Michael Braukus
Headquarters, Washington, D.C.
        N

Mitch Varnes
Kennedy Space Center, Fla.

Robert MacMillin
Jet Propulsion Laboratory, Pasadena, Calif.

Maj. Mike Doble
Department of Defense, Pentagon

LAUNCH ADVISORY

    NASA has rescheduled the launch of a Scout rocket from Space Complex 5 at
Vandenberg Air Force Base, Calif., for Sunday, Nov. 8, carrying a Department of
Defense payload called Miniature Seeker Technology Integration (MSTI).

    This is the fifth launch attempt for the Scout/MSTI vehicle.  Previous
launch attempts have been hampered by range control, power supply and ground
support equipment problems.

    Sunday's launch window opens at 8:42 a.m.  EST and extends until 9:42 a.m.
The launch will be carried live on NASA Select TV. The broadcast also may be
monitored on the V-circuits. This system can be reached by calling
407/867-1260.

    The Scout/MSTI News Center at Vandenberg Air Force Base will be located in
Building 840, the NASA Administrative Headquarters.
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
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=--=--=START=--=--= NASA Spacelink File Name:921106C.REL

11/6/92: VIKING PHOTOS SHOW MARS MAY EXPERIENCE FREQUENT QUAKES

Paula Cleggett-Haleim
Headquarters, Washington, D.C.         November 6, 1992

Jim Doyle
Jet Propulsion Laboratory, Pasadena, Calif.

RELEASE:  92-198



     Mars was once very active tectonically and may still be
shaken by quakes daily, according to scientists using NASA's
Viking Orbiter photos of the red planet's surface.

     In a science paper published today, Drs. Matthew
Golombek, W. Bruce Banerdt and David M. Tralli of the Jet
Propulsion Laboratory and Dr. Kenneth L. Tanaka of the U.S.
Geological Survey said Mars is more seismically active than
the moon, but less so than Earth.

     "Because Mars is smaller than Earth, little more than
half the size, a magnitude 6 quake on Mars would have 10
times the effect it would on Earth," Golombek said.

     Marsquakes of that magnitude may occur about once every
4 and a half years, he said.  A marsquake of about magnitude
4, however, might happen somewhere on the planet once a month
on an average.  Yet, a quake of magnitude 4 would be
detectable throughout the planet, again because of its size
and presumed  structure.

     Tectonic features on Mars are found mostly around the
Tharsis region, a large volcanic plateau with associated
features that cover the entire western hemisphere of the
planet.

     Tectonism in that region occurred mainly during two
periods in the planet's history -- the earliest possibly as
long ago as 4-billion years and the most recent ending
possibly less than one-billion years ago.

     Features that formed during the first seismic period
include many narrow graben or long ditch-like or trough
features with faults along their sides.  Also formed at that
time was a system of concentric wrinkle ridges, larger graben
and rifts, and the deep rift valleys of Mars' great 1,860-
mile-long (3,000-kilometer) canyon, the Valles Marineris.

     During the second period, tectonism caused an enormous
set of radial grabens that extend up to thousands of
kilometers from the center of the plateau and rift zones of
Valles Marineris, along with other prominent features.

     Tectonism and seismic activity have decreased from the
earlier period to the present, Golombek said, as would be
expected if the seismic activity is governed by simple
cooling of the lithosphere -- the rigid outer crust and upper
part of the mantle -- of the planet.

     The scientists said that while Mars is less seismically
active than Earth, their studies predict that about two
marsquakes of magnitude 5 or greater occur per year, about a
hundred quakes of magnitude 3 or greater occur per year.

     "That is a promising prospect for seismological
investigations on future missions to Mars," Golombek said.

     Golombek is the Project Scientist for the Mars
Environmental Survey (MESUR) project which would place a
network of landers, each with a seismometer, in different
locations on the Martian surface.  Recordings of marsquakes
by seismometers at different locations will help determine
the internal structure of the red planet.

     The network of instrumented landers is planned to be
deployed over three Mars launch opportunities.  Four would be
sent in 1999, four more in 2001 and the final eight launched
with four each on two launch vehicles in 2003.

     A precursor mission called MESUR Pathfinder is under
study as part of NASA's proposed Discovery Program of small,
low-cost planetary missions.  MESUR Pathfinder would place a
single lander on Mars with a robotic rover deploying, among
other instruments, a seismometer as early as 1996.

     The paper, published today in Science magazine, is
entitled "A Prediction of Mars Seismicity from Surface
Faulting."

     The Discovery Program and the Viking mission are managed
by NASA's Office of Space Science and Applications, NASA
Headquarters, Washington, D.C.

- end -
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
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International Ultraviolet Explorer (IUE)


The International Ultraviolet Explorer (IUE) project was a joint enterprise,
with  participants from NASA and its contractors, the European Space Agency,
and the British Science Research Council.  IUE-1, launched into geosynchronous
orbit in January 1978, allowed hundreds of users at two locations to conduct
spectral studies of celestial ultraviolet sources.  It was the first satellite
totally dedicated to ultraviolet astromony.

NASA provided the IUE spacecraft, optical and mechanical components of the
scientific instruments, the U.S. ground observatory, and the spacecraft control
software.  ESA contributed the solar arrays IUE-1 needed as a power source and
the European ground observatory in Spain.  The British Science Research Council
oversaw the development of the spectrograph television cameras and, with the
U.S., the image processing software.

The objects of IUE's studies were many: faint stars, quasars, comets, gas
streams, extragalactic objects, and the interstellar medium.  The primary
instrument for these studies was a 45-centimeter Ritchey Chretien telescope.
Geosynchronous orbit permitted  continuous observations and real-time data
access by the many observers who worked at the two ground observatories.  With
the increased time, many "visiting observers" could take advantage of the
ultraviolet astronomy satellite.  NASA's Goddard Space Flight Center controlled
the spacecraft 16 hours of each day, while the European observatory near Madrid
controlled it for 8 hours



IUE Characteristics

Also called:  International Ultraviolet Explorer
Memorandum of Understanding (MOU) between NASA and: European Space Agency and
              U.K. Science Research Council

Date of launch (range):  Jan 26, 1978 (ETR)
Launch vehicle:          Thor-Delta 2914
Shape:                   Octagonal
Weight (kg):             671
Dimensions:              1.3, diam. (4.3 with solar arrays)
                         4.3, length (with telescope tube)
Power source:            solar arrays plus NiCd battery
Prime contractor:        N/A
Date of re-entry:        N/A


NASA's role:  spacecraft launch vehicle, spacecraft support, tracking and data
              acquisition, with ESA providing the solar arrays and a European
              ground observatory and U.K. providing the image tubes for the
              spectrograph and acquisition field camera.


Responsible NASA center:  GSFC

Project manager:          Gerald W. Longanecker

Project scientist:        Albert Boggess


Objectives:  To conduct spectral distribution studies of celestial untraviolet
             sources (see below); ground observatories were established at GSFC
             and at Vallofranca del Castillo.


Experiments:  Satellite function as an observatory for hundreds of users (45-cm
              Ritchey Chretien telescope); scientific goals included:
              to obtain high resolution spectra of stars
              to study gas streams
              to observe faint stars, galaxies, and quasars
              to observe the spectra of planets and comets
              to make repeated observations which show variable spectra
              to define more precisely the modifications of starlight caused by
              interstellar dust and gas

Results:      Highly successful
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
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IUE MONTHLY STATUS REPORT  (10/31/92)

INTERNATIONAL ULTRAVIOLET EXPLORER


       The nearly-15-year-old IUE took more than 300 images during October. The
IUE science team's ongoing study of active galactic nuclei continues.  By
monitoring changes in these mysterious objects, the team is studying accretion
discs -- gas circling around the centers of these objects.  It is theorized
that the center of an active galactic nucleus is comprised of a black hole with
a mass equal to 100 million Suns. The IUE was launched aboard a Goddard-managed
Delta on January 26, 1978.
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
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=--=--=START=--=--= NASA Spacelink File Name:6_12_7.TXT

Mir element set #686 (6-Nov-92)

Mir
1 16609U 86 17  A 92311.49039476  .00021501  00000-0  31377-3 0  6868
2 16609  51.6236 256.6295 0002666  52.6457 307.4724 15.55605330384411

Satellite: Mir
Catalog number: 16609
Epoch time:      92311.49039476
Element set:     686
Inclination:       51.6236 deg
RA of node:       256.6295 deg          Semi-major axis:  3660.0907 n.mi.
Eccentricity:    0.0002666              Apogee altitude:   217.1323 n.mi.
Arg of perigee:    52.6457 deg          Perigee altitude:  215.1808 n.mi.
Mean anomaly:     307.4724 deg          Altitude decay:      0.0337 n.mi./day
Mean motion:   15.55605330 rev/day      Apsidal rotation:    3.7273 deg/day
Decay rate:     2.1501E-04 rev/day~2    Nodal regression:   -4.9919 deg/day
Epoch rev:           38441              Nodal period:       92.5069 min

GIL.CARMAN
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
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=--=--=START=--=--= NASA Spacelink File Name:6_9_9_6.TXT

11/6/92: REPORT DETAILS CAUSES OF TETHERED SATELLITE MALFUNCTIONS

Mark Hess
Headquarters, Washington, D.C.              November 6, 1992

Jerry Berg
Marshall Space Flight Center, Huntsville, Ala.

RELEASE:  92-196


     The report of NASA's Tethered Satellite System
Investigative Board was released today, presenting the
panel's findings on problems which prevented full deployment
of the satellite during Space Shuttle mission STS-46.

     The 47-page report examined five problems that occurred
during the deployment effort and identified causes for four
of them.  It made recommendations for actions to be taken to
prevent similar occurrences in the future.

     The board said the two snags during deployment and
retrieval -- when first releasing the satellite from the
deployer and when the satellite was at 735 feet -- were due
to slack which developed in the tether at a point where it
moves between one pulley and another -- somewhat similar to
movie film misfeeding in a projector.

      "The crew found a way to procedurally get around this
slack problem," said Board Chairman Darrell Branscome.  "In
both cases the jamming was overcome.  By itself, this problem
would not have prevented us from fully deploying the
satellite."

     NASA previously had reported on Aug. 28 that the cause
of the unplanned stops at 587 and 840 feet was a mechanical
obstruction -- a protruding bolt -- which prevented part of
the tether reel mechanism from moving across its full range
of travel.

     "We contacted the bolt when the satellite was out at 587
feet," said Branscome.  "What we learned from our ground
simulations was that in spite of the bolt obstruction, it was
possible to pull additional tether off the reel, out to 840
feet."

     According to the report, the bolt was part of a hardware
change made late in the review process and should have been
caught in the systems engineering review.

     "The board made some excellent recommendations in the
report on how to deal with things like late changes to the
hardware," said Pearson.  "We are going to look carefully at
their recommendations and apply the lessons learned from this
flight to future missions."

     No plausible scenario has been validated by post-flight
demonstration regarding difficulty in retracting one of two
umbilicals between the tethered satellite and deployer.

     Based on its findings, the board recommended several
specific hardware assessments and modifications which should
be made to other elements of the tethered system if NASA
decides to refly it.

     The board was formed on Aug. 12 by Jeremiah Pearson,
NASA Associate Administrator for Space Flight.  The six-
member board included representatives from various NASA
centers and the Italian Space Agency.

- end -


     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
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