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18-May-93 Daily File Collection
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=--=--=START=--=--= NASA Spacelink File Name:930518.REL

5/17/93: MAGELLAN TO TEST AEROBRAKING MANEUVER IN VENUS ATMOSPHERE

Paula Cleggett-Haleim
Headquarters, Washington, D.C.
   M

Franklin O'Donnell
Jet Propulsion Laboratory, Pasadena, Calif.

RELEASE:  93-89


        NASA's Magellan spacecraft will dip into the atmosphere of Venus
beginning May 25 in a first-of-its-kind "aerobraking" maneuver, lowering the
spacecraft's orbit to start a new experiment.

        The aerobraking technique will use the drag created by Venus'
atmosphere to slow the spacecraft and circularize Magellan's orbit.  Currently
Magellan is looping around Venus in a highly elliptical orbit.

        "This aerobraking technique has never been used before on a NASA
planetary mission," said Douglas Griffith, Magellan project manager at NASA's
Jet Propulsion Laboratory, Pasadena, Calif.

        "Magellan has been highly successful in completing all of its primary
mission goals," said Alphonso V. Diaz, Deputy Associate Administrator for
NASA's Office of Space Science. "The new orbit will enhance the scientific
return from what is already one of NASA's most successful space science
missions."

        According to Griffith, aerobraking is the only way to make such a large
change in Magellan's orbit because the spacecraft does not have enough thruster
fuel onboard for the change. "Although aerobraking creates some risk of losing
the spacecraft, the scientific benefits make the risk worthwhile," he said.

        The benefit of changing the orbit is to make possible better
measurements of Venus's gravity field, particularly at latitudes near the
planet's poles, said Dr. R. Stephen Saunders of JPL, the Magellan Project
Scientist.

        For the past 8 months, Magellan has been collecting data on Venus'
gravity.  However, measurements from the current elliptical orbit are blurred
at high latitudes by the height of the spacecraft above the surface -- about
1,300 miles (2,100 kilometers) near the north pole and 1,700 miles (2,800
kilometers) near the south pole.

        Scientists also hope to study Venus's atmosphere using data collected
during the aerobraking experiment itself.  And another objective is to gain the
engineering experience that may allow future missions to use aerobraking to
enter planetary orbit or to change orbit without using large thrusters.

        Launched in May 1989, Magellan will complete its fourth 243-day orbital
cycle at Venus on May 25.  During each of the 8-month cycles, Magellan orbits
from north to south while the planet turns once underneath the spacecraft.

        During earlier cycles, Magellan used its radar to map Venus's surface
with a resolution as fine as 250 feet (75 meters).  Data was obtained on the
elevation, slope, radar reflectivity and radar emissivity over 98 percent of
the planet.

        In the upcoming maneuver, flight controllers hope to lower the
spacecraft from a low point near 100 miles (170 kilometers) and high point of
5,300 miles (8,500 kilometers).  The target orbit is 125 by 375 miles (200 by
600 kilometers).  This would alter orbit time from 3-1/4 hours to 90 minutes.

        The aerobraking experiment will start at 1:30 p.m.  EDT May 25, when
the spacecraft makes the first maneuver.  By controlling the orbit altitude,
the drag and heat generated on the spacecraft will be kept within tolerable
limits.

        Completing the change will take about 80 days.  The short period of
drag on each orbit, a few minutes at the start to about 20 minutes near the
end, will lower the orbital high point by about 6 miles (10 kilometers) on
every orbit.

        Measuring Venus's gravity field permits scientists to measure the
pattern of heavier and lighter regions under the planet's surface.  It is the
only technique currently possible to look inside Venus and provides information
like that gained using seismometers to probe inside a planet.  Similar
measurements on Earth helped reveal plate tectonics, Earth's fundamental
geologic process.

        "Without better measurements from a lower orbit, it would remain very
hard to understand Venus's internal geology and why it is so different from
Earth," said Saunders.

        JPL manages the Magellan mission for NASA's Office of Space Science,
Headquarters, Washington, D.C.

                               -end-

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

=--=--=START=--=--= NASA Spacelink File Name:930518.SHU

KSC SHUTTLE STATUS 5-18


        KENNEDY SPACE CENTER SPACE SHUTTLE STATUS REPORT
                      Tuesday, May 18, 1993

KSC Contact: Bruce Buckingham


-----------------------------------------------------------------
Mission: STS-57/Spacehab/EURECA-Retrieval  Orbital Alt. 287 miles
Vehicle: Endeavour/OV-105                 Inclination: 28 degrees
Location: Pad 39-B                        Crew Size: 6
Target Launch Date/Window: June 3, 6:17 - 7:28 p.m.
Target KSC Landing Date/Time: June 11, 5:14 p.m.
Expected Mission Duration: 7 days/23 hours (if cryogenics allow)

IN WORK TODAY:
*  Pad cleared for hypergolic fuel loading operations through
   Wednesday morning

WORK SCHEDULED:
*  Auxiliary power unit leak checks
*  Engine number 1 heat shield installation
*  Helium signature test
*  Launch Readiness Review (Wednesday)
*  Flight Readiness Review (Friday)

WORK COMPLETED:
*  X-rays and borescope checks of main propulsion system
   (additional inspections may be scheduled at a later date)
*  Orbiter/external tank umbilical foaming operations
*  Close payload bay doors


-----------------------------------------------------------------
Mission: STS-51/ACTS-TOS/ORFEUS-SPAS      Orbital Alt.: 184 miles
Vehicle: Discovery/OV-103                 Inclination: 28 degrees
Location: OPF bay 3                       Crew Size: 5
Mission Duration: 9 days/22 hours
Target Launch Period: mid-July

IN WORK TODAY:
*  Power reactant storage and distribution system tests
*  Orbital maneuvering system functional tests
*  Waste containment system servicing
*  Auxiliary power unit leak and functional checks
*  ORFEUS-SPAS interface verification test

WORK SCHEDULED:
*  ACTS interface verification test (Wednesday)
*  ORFEUS-SPAS end-to-end test (Friday)
*  Flight control checkouts
*  Forward reaction control system installation

WORK COMPLETED:
*  Remote manipulator system functional checks

-----------------------------------------------------------------


Mission: STS-58/SLS-2              Orbital Altitude: 176 miles
Vehicle: Columbia/OV-102           Inclination: 39 degrees
Location: OPF bay 2                Crew Size: 7
Mission Duration: 14 days
Target launch period: Early September


IN WORK TODAY:
*  Orbiter power up operations
*  Ferry kit removal
*  Waste tank removal
*  Hydraulic power-up and re-position elevons

WORK SCHEDULED:
*  Hypergolic fuel purges
*  SLS-2 mission sequence test (May 24-27)
*  Removal of Spacelab D-2 module (Wednesday)

WORK COMPLETED:
*  Open payload bay doors
*  Tailcone removal
*  Payload bay doors latch and functional tests





                          #   #   #   #
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
=--=--=-END-=--=--=

=--=--=START=--=--= NASA Spacelink File Name:930518.SKD

Daily News/TV Sked 5-18-93

Daily   News
Tuesday, May 18, 1993      Two Independence Square, Washington, D.C.
Audio Service: 202/358-3014


 % Preparations for upcoming STS-57 continue;
 % NASA to help AIDS research;
 % International Mars exploration group formed;


As June 3 draws near, technicians continue to prepare Space Shuttle Endeavour
for the STS- 57 mission.  Workers plan to conduct auxiliary power unit leak
checks and conduct a launch readiness review test on Wednesday. The 7 day 23
hour mission is scheduled to conclude with a landing at the Kennedy Space
Center June 11.

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

In an attempt to contribute to a better understanding of the Acquired Immune
Deficiency Syndrome or AIDS, NASA and American Bio-Technologies Inc. have
joined forces.

The goal is to use the advanced x-ray crystallography technology and expertise
developed by the Marshall Space Flight Center to gain more knowledge in regards
to the Human Immunodeficiency Virus (HIV) and AIDS and to develop therapeutic
approaches for HIV and AIDS. The researchers also want to develop biological
materials for vaccine development and HIV detection.

Under the agreement signed on April 26, each organization will bring its
specialized capabilities to the research effort.  Both NASA and American
Bio-Technologies plan to publish the research results.

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

During a meeting in Wiesbaden, Germany on May 10, 1993, NASA, ESA, the Russian
Research Institute, the Italian Space Agency, the German Space Agency and the
French Centre National d'Etudes Spatiales decided to form an International Mars
Exploration Working Group. The group plans to produce an international strategy
for exploring Mars after the year 2000.

This is the first time that the mentioned agencies have agreed to develop a
multilateral strategy for the exploration of Mars. The working group also
intends to examine the possibilities for an International Mars Network mission
and provide a forum for the coordination of future Mars exploration missions.


         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.


Tuesday, May 18, 1993

Live      2:30 pm       EVA or Spacewalk. (JSC)
          4:00 pm       STS-57 Crew Briefing. (JSC)


Wednesday, May 19, 1993

Live    11:00 am        STS-55 Post-Flight Crew Press Briefing.
        NOON    NASA Today News.
        12:15 pm        Aeronautics & Space Report.
        12:30 pm        Progress in Aeronautics.
          1:00 pm       Building Towards New Heights.
          1:30 pm       Jupiter: A Clearer Picture.
          2:00 pm       Reach for the Stars (Replay).
          2:30 pm       Life Into Space.
          3:00 pm       Milam Waters: TQM.
          3:30 pm       A Personal Commitment.



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:6_8_3_12.TXT

5/17/93: MAGELLAN TO TEST AEROBRAKING MANEUVER IN VENUS ATMOSPHERE

Paula Cleggett-Haleim
Headquarters, Washington, D.C.
   M

Franklin O'Donnell
Jet Propulsion Laboratory, Pasadena, Calif.

RELEASE:  93-89


        NASA's Magellan spacecraft will dip into the atmosphere of Venus
beginning May 25 in a first-of-its-kind "aerobraking" maneuver, lowering the
spacecraft's orbit to start a new experiment.

        The aerobraking technique will use the drag created by Venus'
atmosphere to slow the spacecraft and circularize Magellan's orbit.  Currently
Magellan is looping around Venus in a highly elliptical orbit.

        "This aerobraking technique has never been used before on a NASA
planetary mission," said Douglas Griffith, Magellan project manager at NASA's
Jet Propulsion Laboratory, Pasadena, Calif.

        "Magellan has been highly successful in completing all of its primary
mission goals," said Alphonso V. Diaz, Deputy Associate Administrator for
NASA's Office of Space Science. "The new orbit will enhance the scientific
return from what is already one of NASA's most successful space science
missions."

        According to Griffith, aerobraking is the only way to make such a large
change in Magellan's orbit because the spacecraft does not have enough thruster
fuel onboard for the change. "Although aerobraking creates some risk of losing
the spacecraft, the scientific benefits make the risk worthwhile," he said.

        The benefit of changing the orbit is to make possible better
measurements of Venus's gravity field, particularly at latitudes near the
planet's poles, said Dr. R. Stephen Saunders of JPL, the Magellan Project
Scientist.

        For the past 8 months, Magellan has been collecting data on Venus'
gravity.  However, measurements from the current elliptical orbit are blurred
at high latitudes by the height of the spacecraft above the surface -- about
1,300 miles (2,100 kilometers) near the north pole and 1,700 miles (2,800
kilometers) near the south pole.

        Scientists also hope to study Venus's atmosphere using data collected
during the aerobraking experiment itself.  And another objective is to gain the
engineering experience that may allow future missions to use aerobraking to
enter planetary orbit or to change orbit without using large thrusters.

        Launched in May 1989, Magellan will complete its fourth 243-day orbital
cycle at Venus on May 25.  During each of the 8-month cycles, Magellan orbits
from north to south while the planet turns once underneath the spacecraft.

        During earlier cycles, Magellan used its radar to map Venus's surface
with a resolution as fine as 250 feet (75 meters).  Data was obtained on the
elevation, slope, radar reflectivity and radar emissivity over 98 percent of
the planet.

        In the upcoming maneuver, flight controllers hope to lower the
spacecraft from a low point near 100 miles (170 kilometers) and high point of
5,300 miles (8,500 kilometers).  The target orbit is 125 by 375 miles (200 by
600 kilometers).  This would alter orbit time from 3-1/4 hours to 90 minutes.

        The aerobraking experiment will start at 1:30 p.m.  EDT May 25, when
the spacecraft makes the first maneuver.  By controlling the orbit altitude,
the drag and heat generated on the spacecraft will be kept within tolerable
limits.

        Completing the change will take about 80 days.  The short period of
drag on each orbit, a few minutes at the start to about 20 minutes near the
end, will lower the orbital high point by about 6 miles (10 kilometers) on
every orbit.

        Measuring Venus's gravity field permits scientists to measure the
pattern of heavier and lighter regions under the planet's surface.  It is the
only technique currently possible to look inside Venus and provides information
like that gained using seismometers to probe inside a planet.  Similar
measurements on Earth helped reveal plate tectonics, Earth's fundamental
geologic process.

        "Without better measurements from a lower orbit, it would remain very
hard to understand Venus's internal geology and why it is so different from
Earth," said Saunders.

        JPL manages the Magellan mission for NASA's Office of Space Science,
Headquarters, Washington, D.C.

                               -end-

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

=--=--=START=--=--= NASA Spacelink File Name:6_8_5_3_12.TXT

ULYSSES MISSION STATUS 5/17/93

PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109


                     ULYSSES MISSION STATUS
                          May 17, 1993


     All spacecraft and science operations are performing well.
Ground-controllers are carrying out routine data-gathering
activities and experiment reconfigurations as required.  The 34-
meter (112-foot) and 70-meter (230-foot) ground antennas are
tracking the spacecraft as it continues to move farther south of
the ecliptic plane -- the plane in which the planets orbit.


     Earth-pointing maneuvers continue to be carried out about
every five days.  The last maneuver was performed on May 12,
1993.


     Today Ulysses is about 683 million kilometers (424 million
miles) from Earth, traveling at a heliocentric velocity of about
36,000 kilometers per hour (24,000 miles per hour).  The
spacecraft is now more than 30 degrees south of the sun's
equator.


                              #####
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
=--=--=-END-=--=--=

=--=END OF COLLECTION---COLLECTED 5 FILES---COMPLETED 21:06:13=--=