Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/DAILY_2/930728.DFC

Text File | 1993-07-31 | 35KB | 787 lines

28-Jul-93 Daily File Collection
   These files were added or updated between 27-Jul-93 at 21:00:00 {Central}
                                         and 28-Jul-93 at 21:00:23.

=--=--=START=--=--= NASA Spacelink File Name:930728.REL

7/28/93:  NASA ADAPTING UNIQUE X-RAY SYSTEM TO INSPECT AIRCRAFT

Drucella Andersen
Headquarters, Washington, D.C.                                                       July 28, 1993


Kirsten Williams
Langley Research Center, Hampton, Va.



RELEASE:  93-137

     NASA is adapting an existing, cutting-edge x-ray system to improve
inspections of aging aircraft while saving American industries money.

     The x-ray system, which combines TV-like scanning by x-ray beams with
digital data acquisition, was originally intended for medical, dental and other
industrial purposes.  Researchers at NASA's Langley Research Center, Hampton,
Va., have devised several unique aeronautical and aerospace applications for
the system.

     "We want to take advantage of a novel system, slightly modify it and use
it for aircraft," said Dr. Joseph Heyman, Head of Langley's Nondestructive
Evaluation Sciences Branch. "We will use it for measuring composite materials,
for assessing damage growth in materials and for supporting tests to assess how
structures behave under stress."

     To enhance safe air travel, Langley will adapt the system to inspect
aircraft wings, turbines and propeller blades for corrosion, cracks and
disbonding. "This research is part of our mandate to work with the Federal
Aviation Administration to improve safety and reliability," Heyman said.

     Because the system yields depth information, this x-ray technique also may
be used by NASA to view how fibers mesh in three-dimensional composites and to
monitor them for internal damage.  Other potential uses include checking for
changes in solid rocket fuel over time.

     "It's such a broad applications area," Heyman said. "I see it as a general
purpose tool for NASA and for industry."

     Before NASA can employ the machine, researchers must miniaturize the
system's sensors.  They then can be inserted into internal structures to
inspect entire aircraft, including hard-to-reach corners and crevices.  Under a
NASA contract, the Digiray Corp., which developed, patented and marketed the
system, has boosted its power so thicker aircraft parts can be imaged.

      Langley researchers also must come up with methods to ensure the accuracy
of the data and to enhance interpretation of the x-ray image. "We need to
develop computational models that can take the data we obtain using the Digiray
system and essentially map it into something that can be quantitatively
interpreted," said Dr. William Winfree, a NASA senior researcher.

     "Other evaluation methods like ultrasonics and thermography exist, but are
used for different purposes," Winfree added. "We believe that these types of
technologies, which improve image quality, permit reliable airframe inspection
and reduce cost."

Transferring the Technology

     NASA hopes to sign a memorandum of agreement with Digiray Corp. that
approves Langley's applications and adaptations.  NASA has a rigorous
technology transfer program to let aerospace technology permeate the private
sector.

     Langley researchers will share these unique uses of the x-ray technology
with commercial air fleets, as well as other industries.  There also are
potential spin- off uses, such as improved medical x-rays and assembly-line
part scanning to control production quality.

     "This technology cooperation will expand the use for this product and will
help U.S industries maintain product quality," Heyman said. "We as a national
lab should be a resource for U.S. industry, helping them become more
competitive."
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
=--=--=-END-=--=--=

=--=--=START=--=--= NASA Spacelink File Name:930728.SHU

KSC SHUTTLE STATUS REPORT 7/28/93




        KENNEDY SPACE CENTER SPACE SHUTTLE STATUS REPORT
                     Wednesday, July 28, 1993

KSC Contact: Bruce Buckingham


              MISSION: STS-51  ACTS-TOS/ORFEUS-SPAS


VEHICLE: Discovery/OV-103             ORBITAL ALTITUDE: 184 miles
LOCATION: Pad 39-B                    INCLINATION: 28.45 degrees
LAUNCH DATE: August 4                 CREW SIZE: 5
LAUNCH WINDOW: 9:06 - 10:14 a.m. EDT
KSC LANDING DATE/TIME: August 13/14 (7:05 a.m.)
MISSION DURATION: 8 days/22 hours + 1 day (An additional day on
             orbit may be granted if orbiter cryogenics allow.)

NOTE: Launch of Discovery on mission STS-51 is scheduled for Wed- nesday,
August 4, 1993.  The launch window opens at 9:06 a.m.  EDT and extends to 10:14
a.m.  The countdown is scheduled to pick-up at 9:30 a.m. on Sunday, August 1 at
the T-43 hour mark.

IN WORK TODAY:
*  Remove and replace right hand solid rocket booster Auxiliary
   Power Unit (APU)
*  Aft engine compartment closeouts
*  Advanced Communications Technology Satellite battery charging
*  Countdown preparations

WORK SCHEDULED:
*  Reservice APU hypergolic fuels
*  Hot fire SRB hydraulic power unit
*  Reconnect ordnance devices
*  Power reactant storage and distribution system purges
*  Vehicle power down on Saturday

WORK COMPLETED:
*  Deservice of SRB APU hypergolic fuels
*  Raise booster service platforms




           MISSION: STS-58  Spacelab Life Sciences - 2

VEHICLE: Columbia/OV-102              ORBITAL ALTITUDE: 176 miles
LOCATION: OPF bay 2                   INCLINATION: 39.00 degrees
MISSION DURATION: 14 days             CREW SIZE: 7
TARGET LAUNCH PERIOD: Early/Mid September
LAUNCH TIME: Approximately 11:30 a.m. EDT
LAUNCH WINDOW: 2 hours, 30 minutes


IN WORK TODAY:
*  Main engine securing
*  Main engine heatshield and carrier panel installation
*  External tank and solid rocket booster electrical mates in the
   Vehicle Assembly Building

WORK SCHEDULED:
*  Crew equipment interface test
*  Orbiter Aft closeouts

WORK COMPLETED:
*  Spacelab end-to-end tests
*  Spacelab/tunnel integration verification tests
*  Main engine installation and leak checks
*  Install Spacelab tunnel
*  External tank/solid rocket booster mechanical mates



              MISSION: STS-61  Hubble Space Telescope
                                 Servicing Mission


VEHICLE: Endeavour/OV-105             ORBITAL ALTITUDE: 356 miles
LOCATION: OPF bay 1                   INCLINATION: 28 degrees
MISSION DURATION: 11 days             CREW SIZE: 7
TARGET LAUNCH PERIOD: Early December 1993

IN WORK TODAY:
*  5th cryogenic tank set installation preparations
*  Orbital maneuvering system functional checks
*  Ammonia system leak and functional checks
*  Payload integration tests

WORK SCHEDULED:
*  Install 5th cryogenic tank set

WORK COMPLETED:
*  Humidity separator functional checks
*  Main propulsion system inspections
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
=--=--=-END-=--=--=

=--=--=START=--=--= NASA Spacelink File Name:930728A.REL

7/28/93:  SLS-2 PAYLOAD STATUS REPORT

                      PAYLOAD STATUS REPORT
                          STS-58/SLS-2

                         July 28, 1993

George Diller
Kennedy Space Center


     The primary payload for mission STS-58, the Spacelab Life Sciences 2
(SLS-2) laboratory module, passed a processing milestone today with the
completion of the Interface Verification Test (IVT) verifying electrical and
mechanical connections between the Spacelab module and the Spacelab tunnel.
The tunnel, which provides astronaut access between the orbiter mid-deck and
the module itself, contains lights and air-handling equipment for the Spacelab.
It was installed into Columbia's payload bay July 24-25.

     Also successfully completed was an end-to-end test to verify
communications capability between the laboratory in Columbia's payload bay and
the Johnson Space Center in Houston. Columbia and SLS-2 are in Bay 2 of the
Orbiter Processing Facility at KSC. The laboratory module was installed into
Columbia on July 15 and these connections were also verified with an IVT on
July 20-22.

     Next, limited-lifetime experiment lockers were installed within the SLS-2
laboratory on July 22-23.  The most time-critical of the experiments will be
installed at the pad during launch countdown.

     After the experiment lockers were installed in the OPF, the Spacelab
tunnel installation followed last weekend on July 24-25.

     Columbia is targeted to move to the Vehicle Assembly Building on Aug. 15
and roll out to Launch Pad 39-B about a week later.  Once at the pad, ground
support equipment used in experiment activation will be installed inside the
Spacelab module.  The actual SLS-2 activation occurs at the beginning of the
STS-58 launch countdown.

     The SLS-2 mission, like its predecessor, SLS-1, is dedicated to life
sciences research related to the future health, safety and productivity of
humans in space.

     SLS-2 will re-fly many of the SLS-1 investigations to enable scientists to
draw more definitive and statistically significant conclusions.  Fourteen
coordinated and complementary experiments will focus on the physiological
mechanisms involved in the adaptation to microgravity and readaptation to
normal Earth gravity.  The STS-58/SLS-2 mission is targeted for launch the
second week of September.
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
=--=--=-END-=--=--=

=--=--=START=--=--= NASA Spacelink File Name:10_9_4.TXT

7/28/93:  NASA ADAPTING UNIQUE X-RAY SYSTEM TO INSPECT AIRCRAFT

Drucella Andersen
Headquarters, Washington, D.C.                                                       July 28, 1993


Kirsten Williams
Langley Research Center, Hampton, Va.



RELEASE:  93-137

     NASA is adapting an existing, cutting-edge x-ray system to improve
inspections of aging aircraft while saving American industries money.

     The x-ray system, which combines TV-like scanning by x-ray beams with
digital data acquisition, was originally intended for medical, dental and other
industrial purposes.  Researchers at NASA's Langley Research Center, Hampton,
Va., have devised several unique aeronautical and aerospace applications for
the system.

     "We want to take advantage of a novel system, slightly modify it and use
it for aircraft," said Dr. Joseph Heyman, Head of Langley's Nondestructive
Evaluation Sciences Branch. "We will use it for measuring composite materials,
for assessing damage growth in materials and for supporting tests to assess how
structures behave under stress."

     To enhance safe air travel, Langley will adapt the system to inspect
aircraft wings, turbines and propeller blades for corrosion, cracks and
disbonding. "This research is part of our mandate to work with the Federal
Aviation Administration to improve safety and reliability," Heyman said.

     Because the system yields depth information, this x-ray technique also may
be used by NASA to view how fibers mesh in three-dimensional composites and to
monitor them for internal damage.  Other potential uses include checking for
changes in solid rocket fuel over time.

     "It's such a broad applications area," Heyman said. "I see it as a general
purpose tool for NASA and for industry."

     Before NASA can employ the machine, researchers must miniaturize the
system's sensors.  They then can be inserted into internal structures to
inspect entire aircraft, including hard-to-reach corners and crevices.  Under a
NASA contract, the Digiray Corp., which developed, patented and marketed the
system, has boosted its power so thicker aircraft parts can be imaged.

      Langley researchers also must come up with methods to ensure the accuracy
of the data and to enhance interpretation of the x-ray image. "We need to
develop computational models that can take the data we obtain using the Digiray
system and essentially map it into something that can be quantitatively
interpreted," said Dr. William Winfree, a NASA senior researcher.

     "Other evaluation methods like ultrasonics and thermography exist, but are
used for different purposes," Winfree added. "We believe that these types of
technologies, which improve image quality, permit reliable airframe inspection
and reduce cost."

Transferring the Technology

     NASA hopes to sign a memorandum of agreement with Digiray Corp. that
approves Langley's applications and adaptations.  NASA has a rigorous
technology transfer program to let aerospace technology permeate the private
sector.

     Langley researchers will share these unique uses of the x-ray technology
with commercial air fleets, as well as other industries.  There also are
potential spin- off uses, such as improved medical x-rays and assembly-line
part scanning to control production quality.

     "This technology cooperation will expand the use for this product and will
help U.S industries maintain product quality," Heyman said. "We as a national
lab should be a resource for U.S. industry, helping them become more
competitive."
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
=--=--=-END-=--=--=

=--=--=START=--=--= NASA Spacelink File Name:6_12_7.TXT

Mir element set #203

Mir
1 16609U 86 17  A 93208.76781959  .00007547  00000-0  10161-3 0  2031
2 16609  51.6205  15.7183 0004035 258.7032 101.3474 15.58956370425467

Satellite: Mir
Catalog number: 16609
Epoch time:      93208.76781959
Element set:     203
Inclination:       51.6205 deg
RA of node:        15.7183 deg          Semi-major axis:  3654.8438 n.mi.
Eccentricity:    0.0004035              Apogee altitude:   212.3844 n.mi.
Arg of perigee:   258.7032 deg          Perigee altitude:  209.4349 n.mi.
Mean anomaly:     101.3474 deg          Altitude decay:      0.0118 n.mi./day
Mean motion:   15.58956370 rev/day      Apsidal rotation:    3.7472 deg/day
Decay rate:     7.5470E-05 rev/day~2    Nodal regression:   -5.0173 deg/day
Epoch rev:           42546              Nodal period:       92.3079 min
Checksum:              305

G.L.CARMAN
Johnson Space Center
                                                                                         Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
=--=--=-END-=--=--=

=--=--=START=--=--= NASA Spacelink File Name:6_2_2_46_5.TXT

7/28/93  STS-51 LAUNCH ADVISORY:  STS-51 LAUNCH SET FOR AUG. 4

Ed Campion
July 28, 1993
Headquarters, Washington, D.C.


Bruce Buckingham
Kennedy Space Center, Fla.


     NASA managers yesterday set Aug. 4, 1993, as the new launch date for
Shuttle Mission STS-51. The launch window opens at 9:06 a.m. and closes at
10:14 a.m.  EDT.

     The Aug. 4 decision follows the completion of work to remove and replace
the hydraulic power unit (HPU) on the right hand solid rocket booster.  During
a launch attempt on July 24, a computer detected that one of the HPU systems
was not operating at the correct speed and halted the countdown.

     Discovery's five person crew will deploy the Advanced Communciations
Technology Satellite and also will deploy and retrieve the Orbiting and
Retrievable Far and Extreme Ultraviolet Spectrometer.




7/20/93:  LAUNCH ADVISORY:  JULY 24 NEW DATE FOR STS-51 LAUNCH



Ed Campion
July 20, 1993
Headquarters, Washington, D.C.

Bruce Buckingham
Kennedy Space Center, Fla.


     NASA managers today set July 24 as the new launch date for Shuttle Mission
STS-51. The launch window on July 24 opens at 9:27 a.m.  EDT and extends for 54
minutes.

     The decision to go with July 24 as the new launch date follows the
completion of work to inspect and retest the Pyro Initiator Controller (PIC)
unit on the launch pad.  A problem with the unit caused the Kennedy Space
Center launch director to call a scrub during a launch attempt on July 17.

     "The July 24 date is the best date all around for the launch of Discovery
on the STS-51 mission" said Shuttle Director Tom Utsman. It gives enough time
for KSC technicians to complete work on the PIC unit, the payload community
time to service the STS-51 experiments and the entire launch team enough time
to put the Shuttle system back into launch configuration.  The July 24 date
also is one that the Air Force range safety community can support."

     Shuttle Mission STS-51 will see Discovery's five person crew deploy the
Advanced Communciations Technology Satellite which will give industry, academic
and government organizations an opportunity to investigate new ways of
communicating.  The crew will also deploy and retrieve the Orbiting and
Retrieveable Far and Extreme Ultraviolet Spectrometer (ORFEUS- SPAS).






7/01/93:  LAUNCH DATE SET FOR STS-51/DISCOVERY

Jim Cast
Headquarters, Washington, D.C.             July 1, 1993

Bruce Buckingham
Kennedy Space Center, Fla.


NOTE TO EDITORS:  N93-38

    Following today's STS-51 Flight Readiness Review at NASA's Kennedy
Space Center, Fla., mission managers targeted July 17 at 9:22 a.m.  EDT for
launch of the Space Shuttle Discovery on its 17th flight.

    Primary payload activity on the 9-day mission will include deployment
of an Advanced Communications Technology Satellite (ACTS), and deployment and
retrieval of the German- built ORFEUS-SPAS astrophysics free-flier.  A 6-hour
Extra Vehicular Activity, or space walk, will also be performed by two
astronauts.

    Commanding the STS-51 crew is Frank Culbertson who will be making his
second space flight.  Pilot Bill Readdy has also flown once in space.  Three
mission specialists, each flying for the first time, round out the 5-man crew:
Jim Newman, Dan Bursch and Carl Walz.

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

=--=--=START=--=--= NASA Spacelink File Name:6_2_2_47_3.TXT

7/28/93:  SLS-2 PAYLOAD STATUS REPORT

                      PAYLOAD STATUS REPORT
                          STS-58/SLS-2

                         July 28, 1993

George Diller
Kennedy Space Center


     The primary payload for mission STS-58, the Spacelab Life Sciences 2
(SLS-2) laboratory module, passed a processing milestone today with the
completion of the Interface Verification Test (IVT) verifying electrical and
mechanical connections between the Spacelab module and the Spacelab tunnel.
The tunnel, which provides astronaut access between the orbiter mid-deck and
the module itself, contains lights and air-handling equipment for the Spacelab.
It was installed into Columbia's payload bay July 24-25.

     Also successfully completed was an end-to-end test to verify
communications capability between the laboratory in Columbia's payload bay and
the Johnson Space Center in Houston. Columbia and SLS-2 are in Bay 2 of the
Orbiter Processing Facility at KSC. The laboratory module was installed into
Columbia on July 15 and these connections were also verified with an IVT on
July 20-22.

     Next, limited-lifetime experiment lockers were installed within the SLS-2
laboratory on July 22-23.  The most time-critical of the experiments will be
installed at the pad during launch countdown.

     After the experiment lockers were installed in the OPF, the Spacelab
tunnel installation followed last weekend on July 24-25.

     Columbia is targeted to move to the Vehicle Assembly Building on Aug. 15
and roll out to Launch Pad 39-B about a week later.  Once at the pad, ground
support equipment used in experiment activation will be installed inside the
Spacelab module.  The actual SLS-2 activation occurs at the beginning of the
STS-58 launch countdown.

     The SLS-2 mission, like its predecessor, SLS-1, is dedicated to life
sciences research related to the future health, safety and productivity of
humans in space.

     SLS-2 will re-fly many of the SLS-1 investigations to enable scientists to
draw more definitive and statistically significant conclusions.  Fourteen
coordinated and complementary experiments will focus on the physiological
mechanisms involved in the adaptation to microgravity and readaptation to
normal Earth gravity.  The STS-58/SLS-2 mission is targeted for launch the
second week of September.
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
=--=--=-END-=--=--=

=--=--=START=--=--= NASA Spacelink File Name:6_8_15_2_2.TXT

PLUTO FAST FLYBY FACT SHEET
March 1993

Solar System Exploration Division

* MISSION SUMMARY *

Pluto, the smallest planet in our solar system, has remained enigmatic
since its discovery by astronomer Clyde Tombaugh in 1930.  Pluto is
the only planet not yet viewed close-up by spacecraft, and given its
great distance and tiny size, study of the planet continues to
challenge and extend the skills of planetary astronomers.  Most of
what we know about Pluto we have learned since the late 1970s.  Such
basic characteristics as the planet's radius and mass were virtually
unknown before the discovery of Pluto's moon Charon in 1978.  Since
then, observations and inferences about Pluto-Charon, now considered a
"double-planet" system, have progressed steadily to a point where many
of the key questions about the system must await the close-up
observation of a space flight mission.

** Insert PFFCRAFT.GIF **

For example, there is a strong variation in brightness, or albedo, as
Pluto rotates, but we do not know if what we are seeing is a system of
varied terrains, or areas of different composition, or both.  We need
a much closer look to understand these features and the chemical,
geological and perhaps orbital history they represent.  We know there
is a dynamic, largely nitrogen and methane atmosphere around Pluto
that waxes and wanes with the planet's elliptical orbit around the
sun, but we need to understand how the atmosphere arises, persists, is
again deposited on the surface, and how some of it escapes into space.
Telescopic studies indicate that Pluto and Charon are very different
bodies, Pluto being more rocky, Charon more icy.  How and when the two
bodies in a double-planet system could have evolved so differently is
a question that awaits data from close-up observation.

More fundamentally, beyond our basic interest in Pluto and Charon, is
the likelihood that these bodies hold important keys to our
understanding of the giant planets and comets and their role in the
formation of the solar system.  From the Voyager missions to the outer
planets and their moons, we have a basic inventory of the
characteristics of the icy and rocky bodies of the outer solar system.
We have learned much about such planet-like bodies as the moons Triton
and Titan, and are beginning to understand Pluto as a third member of
this triad of small outer "planets." Data about Pluto and Charon,
gathered using ground-based and Earth-orbiting observatories like the
Hubble Space Telescope, continually improve our understanding of these
bodies and have helped define the important questions about Pluto-
Charon.  To address these questions, NASA is now studying a robotic
reconnaissance mission to Pluto-Charon called PLUTO FAST FLYBY.

Pluto Fast Flyby will be unique in its approach.  In order to minimize
cost, while containing the risks associated with lower cost, Pluto
Fast Flyby is being conceived as a pair of very small spacecraft,
using, where possible, lightweight advanced-technology hardware
components.  The baseline Pluto Fast Flyby mission, based on a 1996
new start authorization, calls for launch of the two ~110-150 kg
spacecraft in 1999-2000 toward encounters with Pluto and Charon around
2006-8.  Pluto began receding from the Sun in 1989, and its thin
atmosphere is condensing out into surface frost as it cools.
Therefore, minimizing flight time and launching at an early
opportunity is important for the mission's atmospheric and surface
science objectives (see below).  There is a direct relationship
between spacecraft weight and flight time, so spacecraft design
tradeoff analyses are particularly critical for this mission.

* PLUTO FAST FLYBY SCIENCE OBJECTIVES *

o    Characterize Pluto's and Charon's global geology and geomorphology.

o    Map the surface composition of both sides of each body.

o    Characterize Pluto's neutral atmosphere, measuring its
     composition, thermal structure, and aerosol content.


* CANDIDATE EXPERIMENTS *

o    Visible Imaging System: a charge-coupled device (CCD) imaging
     camera to map surface features and geomorphology of Pluto and
     Charon, and to search for small satellites.

o    Infrared Mapping Spectrometer (perhaps sharing foreoptics with
     the CCD camera) to study the surface composition of Pluto and
     Charon.

o    Ultraviolet Spectrometer to measure atmospheric composition.

o    Radio Science Uplink Occultation Experiment to profile
     temperature and pressure of the atmosphere from the surface
     through the ionosphere.


** Insert PFFTRJCT.GIF **


* MISSION CHARACTERISTICS *

TRAJECTORY:              Two spacecraft, on direct trajectories (i.e.,
                         no gravity-assists)
LAUNCH VEHICLES:         Titan IV/Centaur or Proton; both would entail
                         kick stages
LAUNCH DATES:            1999-2000, assuming a 1996 new start
CRUISE:                  6.5-8.5 years, depending on mass
CRUISE SCIENCE:          None planned, but asteroid flyby, other
                         imaging, H/He detection, and radio science
                         are possible
ARRIVAL AT PLUTO-CHARON: 2006-2008, depending on mass and assuming a
                         1996 new start
FLYBYS:                  PFF-1 @ 10,000 km; PFF-2 TBD based on PFF-1
                         results; both flybys @12-18 km/sec
DATA RETURN:             Onboard storage capability of at least 400Mb
                         per spacecraft; science data downlink at 25-
                         40 bps to 34-meter ground stations


** Insert PFFLNDRW.GIF **


* BASELINE SPACECRAFT CHARACTERISTICS *

TYPE:                    Highly miniaturized descendant of the present
                         class of outer solar system platforms:
                         aluminum hexagonal bus, no deployables
MASS:                    Less than 150 kg; goal is 110-120 kg
                         (7 kg total instrument allocation)
Power:                   RTG source providing 65 watts at Pluto
Communication:           X-Band transponder; 1.47 meter high-gain antenna
Propulsion:              Pressure-fed hydrazine monopropellant design
                         delivering 350 m/s delta-V
Attitude Control:        Widefield star sensor and three solid-state
                         rate sensors
Pointing Knowledge:      Will exceed 1.5 mrad; stability of 10 urad
                         over 1 sec
Slewing Ability:         90 in 3 minutes via cold nitrogen gas
                         thrusters


                    THE PLUTO FAST FLYBY CHALLENGE:
                  A BIG MISSION FOR SMALL SPACECRAFT

Recent interplanetary spacecraft like Galileo and the upcoming Cassini
have been designed relatively large and heavy in order to bring a
maximum exploration payload (including probes) through gravity assists
and the intense radiation of Jupiter.  A large mission of this type to
Pluto had been under consideration since the Voyager 2 encounter with
the frigid Neptunian moon Triton in 1989.  The encounter revealed to a
surprised science community that Triton had polar ice caps, evidence
of seasonal changes, active volcanism, and an atmosphere.  The
implications for Pluto and Charon were recognized immediately, and
spurred plans for a Cassini-class mission.  But recent emphasis at
NASA on smaller, cheaper, and faster missions pointed toward the
possibility of a much smaller mission to Pluto-Charon.  The key for
such a mission is to deliver a scientifically useful payload to the
distant system at minimum cost, and to do so before Pluto's atmosphere
collapses (in about 2020).

The Pluto Fast Flyby baseline emerged from careful consideration of a
complex web of tradeoff analyses regarding trajectory, weight, risk,
and durability, within an envelope of low-cost and scientific goals.
The overall scientific goals for a mission to Pluto and Charon were
articulated and prioritized by NASA's Outer Planet Science Working
Group (OPSWG) and endorsed by the Solar System Exploration
Subcommittee of the NASA Advisory Council.  The goals adopted for
Pluto Fast Flyby are the three first-priority goals of the OPSWG:
study of the geology and morphology, mapping of the surface
composition, and neutral atmosphere.
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
=--=--=-END-=--=--=

=--=--=START=--=--= NASA Spacelink File Name:9_6_14_2.TXT

THE NIGHT SKY  --Binoculars in Astronomy

Exerpt from The Night Sky.

Most of us have taken the time to look up into the sky to observe the Moon and
the stars.  But most of us do not have an astronomical telescope to make
detailed observations of celestial objects.  There is a common item that you
may have at home that can be used for astronomy; binoculars.

Binoculars are actually matched telescopes.  Both oculars have the same sized
lenses and give identical magnifications.  If they did not it would be
uncomfortable to view with both eyes at the same time.  All binoculars have
important information printed somewhere on their exterior.  What looks like a
multiplication problem is really a description of two characteristics of the
binoculars.  The most common type of binocular is the 7x 35.  This is not an
equation. 7x refers to the magnification, or power, of the binoculars.  These
binoculars magnify 7 times.  They will make things look seven times closer or
seven times larger.

The 35 refers to the size of the front lenses.  They are 35 millimeters in
diameter.  The larger these lenses, known as objective lenses, the more light
the binoculars can gather.  This is important in astronomy where it is
important to gather as much light as possible.

Another common type of binocular is the 7x 50.  These have the same
magnification as the first pair, 7, but their objectives are 50 millimeters
across.  They have almost one and a half times the light gathering area as the
7x 35s.  There are binoculars designed for astronomical viewing.  Common
astronomical binoculars are 11x 80, that is magnification = 11, objective
diameter = 80mm.  With such a high magnification their field of view is much
smaller than that of the 7x pair.  Therefore any unsteadiness in holding the
binoculars will make the object being viewed jump around quite a bit. 11x 80s
also weigh 2.25 kilograms.  To view anything comfortably they have to be
mounted on a tripod.

Any binoculars can be used to view the sky.  They should be steadied on a
tripod or some stable object whenever possible.  The Moon is the finest object
to view and a tremendous amount of detail can be seen on its surface.
Different features can be seen as the Moon moves through its phases.  The Moon
is usually visible at some point during the day which makes viewing more
convenient.  The planet Venus is usually visible as a bright object in the
evening or morning sky.  If your binoculars are very steady you may be able to
see that the planet does not appear as a sphere but as a crescent.  Mars has a
distinctive orange color and Jupiter's four large moons, known as the Galilean
satellites, can be seen in a row.  They may all be lined up on one side of the
planet or another or distributed on both sides.  Some may not be visible as
they pass in front of or behind Jupiter.

Stars have distinctive colors.  Some are orange, some are yellow like our Sun,
and some are blue-white.  Use your eyes try to find stars with different colors
and then try to observe them with the binoculars.  Fuzzy patches of sky are
revealed through binoculars to be glowing gas clouds or clusters of stars.  In
the summer sky look for the constellation of Sagittarius which rises after dark
in the southeast.  Sagittarius looks sort of like a teapot.  It is also located
in the Milky Way. There are a large number of gas clouds, called nebulae, and
star clusters above the teapot's spout.  One easily viewed object above the
teapot's spout is the Lagoon Nebula. It is a region where stars are being
formed.  It will look like a bright extended smudge through binoculars.  San
around the region and higher in the sky along the Milky Way to see more objects
and star fields.

In the winter sky look for the constellation of Orion. He has the distinctive
pattern three stars in a row forming his belt.  Below the belt is a large gas
cloud known as the Orion Nebula. It is an excellent object to view through
binoculars.  It, like the Lagoon Nebula, is an area of star formation.

Although it is impossible to predict the next time a bright comet will become
visible from Earth, the next time one does use your binoculars to view it.
Binoculars are better than telescopes since telescopes give you too narrow a
field of view.  Comets are long, extended objects.

Many stars are actually double or multiple star systems.  In many cases, steady
binoculars can split star pairs apart.  An easy pair are the stars Alcor and
Mizar. They are side by side and appear as the middle star in the handle of the
Big Dipper. Keen eyed observers will actually be able to see that there are two
stars by using only their eyes.  There is actually a third star in the group.

Another beautiful pair is the star Albireo at the tip of the nose of Cygnus the
Swan. It is also in the center of the Summer Triangle formed by the stars Vega,
Altair and Deneb. Albireo is two stars of different colors.  A sharp eye and
steady binoculars are necessary.

Many books on binocular observing can be found in your local library.  In
addition, popular astronomy magazines frequently feature articles on observing
methods and objects.



Bibliography

Touring the Universe Through Binoculars: A Complete Astronomer's Guidebook by
Philip S. Harrington; John Wiley & Sons, N.Y. 1990;

Deep-Sky Objects for Binoculars by John T. Kozak, Sky Publishing, Cambridge MA
1988

Exploring the Night Sky with Binoculars by Patrick Moore, Cambridge University
Press, N.Y. 1986;

Astronomy Magazine, 21027 Crossroads Circle, P.O. Box 1612, Waukesha WI 53187;
[phone]; the August 1992, edition had a Binocular Buyers Guide;

Sky and Telescope Magazine, P.O. Box 9111, Belmont MA 02178-9111; (800)
253-0245.


For more information on astronomy and space science contact your regional
Teacher Resource Center, the Jet Propulsion Laboratory Teaching Resource
Center, NASA Spacelink, your local library or The Night Sky, c/o Mail Stop 186,
Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena CA 91109.
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
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