MARSBUGS:  
The Electronic Exobiology Newsletter
Volume 4, Number 7, 11 May, 1997.

Editors:

David Thomas, Department of Biological Sciences, University of 
Idaho, Moscow, ID, 83844-3051, USA, thoma457@uidaho.edu or 
Marsbugs@aol.com.

Julian Hiscox, Microbiology Department, BBRB 17, Room 361, 
University of Alabama at Birmingham, Birmingham, AL 35294-2170, 
USA, Julian_hiscox@micro.microbio.uab.edu.

MARSBUGS is published on a weekly to quarterly basis as warranted 
by the number of articles and announcements.  Copyright of this 
compilation exists with the editors, except for specific 
articles, in which instance copyright exists with the 
author/authors.  E-mail subscriptions are free, and may be 
obtained by contacting either of the editors.  Contributions are 
welcome, and should be submitted to either of the two editors.  
Contributions should include a short biographical statement about 
the author(s) along with the author(s)' correspondence address.  
Subscribers are advised to make appropriate inquiries before 
joining societies, ordering goods etc.  Back issues may be 
obtained via anonymous FTP at:  ftp.uidaho.edu/pub/mmbb/marsbugs.

The purpose of this newsletter is to provide a channel of 
information for scientists, educators and other persons 
interested in exobiology and related fields.  This newsletter is 
not intended to replace peer-reviewed journals, but to supplement 
them.  We, the editors, envision MARSBUGS as a medium in which 
people can informally present ideas for investigation, questions 
about exobiology, and announcements of upcoming events.  
Exobiology is still a relatively young field, and new ideas may 
come out of the most unexpected places.  Subjects may include,  
but are not limited to:  exobiology proper (life on other  
planets), the search for extraterrestrial intelligence (SETI), 
ecopoeisis/ terraformation, Earth from space, planetary biology, 
primordial evolution, space physiology, biological life support  
systems, and human habitation of space and other planets.
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INDEX

5)	NEW EXTRA-SOLAR PLANET DISCOVERED; CIRCULAR ORBIT SUGGESTS IT FORMED LIKE PLANETS IN OUR SOLAR SYSTEM
	Harvard-Smithsonian Center for Astrophysics

6)	SHUTTLE EXPERIMENT TO STUDY MEDICINAL PROPERTIES OF PLANTS
	NASA release:  97-62

7)	NASA'S STARDUST TEAM STUDIES HALE-BOPP'S COMETARY COUSIN
	JPL release

8)	NASA REVISES INTERNATIONAL SPACE STATION SCHEDULE
	NASA release:  97-65

9)	NASA EXPLAINS HOW MOLECULAR-SIZED GEARS MIGHT WORK
	NASA release:  97-75

10)	CHRONOLOGY OF LUNAR AND PLANETARY EXPLORATION AVAILABLE

11)	MICROGRAVITY SCIENCE LABORATORY MISSION SET FOR JULY; REMAINING 1997 SHUTTLE MANIFEST ADJUSTED SLIGHTLY
	NASA release:  97-81

12)	STUDENT WINNERS TO BE HONORED IN WASHINGTON, DC
	NASA release:  97-84

13)	NASA AWARDS 36 MICROGRAVITY RESEARCH GRANTS
	NASA release: 97-86

14)	HUYGENS SPACE PROBE READY TO LEAVE EUROPE
	ESA press release

15)	MARS GLOBAL SURVEYOR FLIGHT STATUS REPORTS
	JPL releases

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NEW MISSIONS SELECTED TO STUDY EARTH'S FORESTS AND GRAVITY FIELD 
VARIABILITY
NASA release:  97-46

Small, lower-cost spacecraft to study the distribution of Earth's 
forests and the variability of its gravity field have been 
competitively selected by NASA for development under a new Office 
of Mission to Planet Earth program called Earth System Science 
Pathfinders (ESSP).

The Vegetation Canopy Lidar (VCL) mission, led by Dr. Ralph 
Dubayah of the University of Maryland, College Park, seeks to 
provide the first global inventory of the vertical structure of 
forests across Earth using a multibeam laser- ranging device. VCL 
will enable direct measurement of tree heights, forest canopy 
structure, and derived parameters such as global biomass with at 
least ten times better accuracy than existing assessments.
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GUIDELINES FOR THE PLANETARY SOCIETY'S NEAR-EARTH OBJECT GRANT 
PROGRAM

OBJECTIVES

The Planetary Society Near-Earth Object (NEO) Grant Program seeks 
to encourage the discovery and exploration of NEOs by supporting 
observation projects and related research around the world.  The 
Society intends these grants to accelerate the NEO discovery 
rate, to improve and increase observations, and to encourage 
international cooperation in this field.

CATEGORIES

The Planetary Society invites applications in one or more of the 
following categories:

1.	NEO Observational Programs.  Projects in this category could 
include discovery programs and those projects that might increase 
the rate of discovery.  For example, an observation program by an 
amateur or at a small observatory could provide follow-up to 
discoveries, and thereby free observers at larger telescopes for 
more discovery work.  Such a program would qualify for a 
Planetary Society grant.

2.	NEO Research Programs.  The category will include all those 
fields relating to understanding NEOs and their roles in the 
evolution of Earth and the solar system. Spectroscopy 
measurements and analysis would be an example of a project in 
this category.

3.	International Collaboration in NEO Observations. Projects in 
this category include those that develop international 
collaboration through cooperative research, or those that enable 
amateurs and researchers at smaller observatories to participate 
in NEO observations and data analysis.

SELECTION CRITERIA

The selection committee will consider how a project enables 
discoveries, advances knowledge, and/or enhances international 
scientific collaboration.  Projects will also be judged on their 
feasibility, creativity, originality, significance and likelihood 
of completion.

The committee will give special consideration to "seed" grants -- 
where a little help now can generate high leverage for future 
work.  Amateurs and scientists and observers from developing 
countries will be given special consideration.

AMOUNTS OF GRANTS

The average grant will be $5,000 to $10,000, although the 
selection committee will consider a range from $1,000 to $25,000, 
depending on need and expected results.  The amount available is 
made possible by the donations of Planetary Society members.

ELIGIBILITY

Anyone anywhere may submit an application for a Planetary Society 
Near-Earth Object grant. We will accept only one application per 
individual or group.

An application submitted on behalf of a group must clearly 
indicate the person acting as the group's representative or 
principal investigator.  That person must sign the application 
form. Should a group project be chosen, the grant will be 
presented to the group's representative or principal 
investigator.  The Planetary Society will have no obligation to 
any other member of the group.

APPLICATIONS

Applications may be submitted at anytime.  To be considered, an 
application must be neatly printed in English by letter, no more 
than three pages in length.  Supporting documentation may be 
submitted or referenced.

Send your application to:

NEO Grant Program
The Planetary Society
65 North Catalina Avenue
Pasadena, CA 91106-2301
USA

Applicants should send copies, not originals, of supporting 
documents, figures or photographs. No applications will be 
returned.  Supporting materials must arrive with the application 
form unless prior arrangements are made.

NOTIFICATION

Grant recipients will be notified of their award as soon as a 
decision is made.  No other notification will be sent by The 
Planetary Society before this date, except for requests by the 
selection committee for supplementary information.

SELECTION ADVISORY COMMITTEE

The selection advisory committee for the NEO grants will be 
composed of internationally renowned scientists.  The final 
selection will be made by the Board of Directors of The Planetary 
Society.  The committee's procedures and deliberations will be 
kept confidential.


PUBLICATION OF AWARDS

Winners of the Planetary Society NEO grants will be published in 
The Planetary Report and The NEO News.  The Society reserves the 
right to publish summaries of the most interesting projects in 
either publication.  The Society also encourages professional 
publications and other popular promotion and articles, so long as 
proper credit is given for any support.

OBTAINING AN APPLICATION

Write to The Planetary Society at the address noted above, or 
call (818) 793-5100.
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NASA ANNOUNCES LIFE SCIENCES RESEARCH GRANTS
NASA release: 97-57

March 27, 1997

NASA has selected 52 proposals to receive one- to four-year 
grants for conducting ground-based or space-borne life sciences 
research, totaling approximately $6.7 million.

NASA Life Sciences grants provide investigators with the 
opportunity to study and characterize basic biological mechanisms 
in ways not possible on Earth.  By utilizing access to space as a 
research tool, NASA-sponsored research will advance fundamental 
knowledge of the ways in which weightlessness, radiation, and 
other aspects of the space environment interact with biological 
processes.  These grants also seek to further the application of 
this knowledge to procedures and technologies that enable humans 
to live, work, and explore in space and that benefit the health 
and well-being of people on Earth.

The purpose of these grants is to enhance scientific and 
technological research in space life sciences.  The grants 
selected for funding were submitted to NASA in May 1996 in 
response to formal research announcements.  The announcements 
requested proposals for research on Earth and during spaceflight 
to address fundamental questions of the ways gravity influences 
fundamental biological processes.

NASA received 443 proposals in response to these research 
announcements.  The proposals were subjected to independent peer 
review through panels made up of external scientific and 
technical experts.  The selected proposals represent the 
following areas:  advanced life support (8), behavior and 
performance (2), space physiology and countermeasures (17), space 
human factors engineering (2), space biology (18), advanced 
technology development (1), advanced environmental monitoring and 
control (3), and environmental health (1).

Sponsored by NASA's Office of Life and Microgravity Sciences and 
Applications in Washington, DC, these announcements offer 
investigators the opportunity to take advantage of NASA's 
research facilities.
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PRECISION PHOTOMETRY TECHNIQUE TO AID SEARCH FOR EXTRASOLAR 
PLANETS
Harvard-Smithsonian Center for Astrophysics

March 18, 1997

CAMBRIDGE, MA -- As astronomers continue to find evidence for 
planets outside our solar system, scientists from the Harvard-
Smithsonian Center for Astrophysics (CfA), Mount Wilson 
Observatory, and Tennessee State University have discovered that 
those stars suspected of having planets may also share certain 
traits. With this knowledge, observers should be able to hone 
their searches and increase their chances of finding other 
planets.

Using a robotic instrument, known as an automatic photoelectric 
telescope (APT), at the Fred Whipple Observatory near Amado, AZ, 
and the 60-inch (1.52-m) telescope at the Mt. Wilson Observatory 
near Los Angeles, the team of scientists was able to measure to 
new levels of precision both the surface magnetism and brightness 
variations of the seven stars identified to have orbiting 
companions. This is a crucial step toward detecting other 
possible planetary systems.

Planets around distant stars are too small and too faint to see 
directly, as the light from the star simply overwhelms any 
planetary glow, so scientists must look for other evidence of 
their presence. One approach depends on the gravitational tug-of-
war between a star and its companion which creates a measurable 
wobble in the star's velocity. Such velocity measurements, 
however, can only find planets the size of Jupiter or larger.

According to Sallie Baliunas of the CfA who led the team of 
researchers, the APT's measurements of tiny variations of a 
star's brightness can reveal Earth-sized objects orbiting that 
star. This is possible by detecting a minute dimming in the light 
from a star as an Earth-sized planet crosses in front of it. 
While the seven suspected planetary systems Baliunas and her 
colleagues examined did not reveal any Earth-sized planets, the 
scientists remain hopeful their technique will reveal such 
objects. The task is not easy, since to detect a planet using 
this method, a planet would have to cross the face of a star 
almost exactly along our line of sight, an orientation that 
occurs only a fraction of the time.

Fortunately, Baliunas and her colleagues found that those stars 
harboring planets share the trait of being "magnetically quiet," 
that is, they have little sunspot or other magnetic activity. In 
addition, the researchers determined that six of the seven stars 
with low-mass orbiting companions were about 5 billion years old, 
or about the same age as our Sun. This suggests astronomers can 
focus their investigations on the middle-aged, magnetically quiet 
stars, thus making searches for planetary systems more efficient.

"This work not only helps support the suggestion of planets 
around Sun-like stars, but it tells us something about the 
properties of these stars," said Baliunas. "That gives better 
targets for the projects that are attempting to pick up radio 
signals from extra-terrestrial intelligence, since the older age 
of these stars suggests any life on surrounding planets might 
have had enough time to develop communications technology."

The technique's unprecedented levels of photometric precision may 
have already helped defuse a possible controversy about the best 
known of the extra-solar planets objects -- the Jupiter-sized 
body thought to be orbiting the star 51 Pegasi. Discovered in 
late 1994, the object has served as a model for finding low-mass 
stellar companions using radial velocity observations. However, 
at least one critic has claimed that variations in the optical 
signal from 51 Pegasi might really be due to natural oscillations 
in the star itself. To test this theory, the research team 
observed the star with its high-precision photometry technique 
and found no evidence for cyclic brightness variations that 
should result from such oscillations.

The research team includes Baliunas, Robert Donahue, Steven Saar, 
and Willie Soon of the CfA, and Greg Henry and Frank Fekel of the 
Center for Excellence in Information Systems at Tennessee State 
University, an HBCU (Historically Black College or University).

This work was supported by NASA, the National Science Foundation, 
and the Richard C. Lounsberg Foundation, and was reported in the 
January 1, 1997 issue of The Astrophysical Journal and the 
January 15, 1997 issue of The Astrophysical Journal Letters.
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NEW EXTRA-SOLAR PLANET DISCOVERED; CIRCULAR ORBIT SUGGESTS IT 
FORMED LIKE PLANETS IN OUR SOLAR SYSTEM
Harvard-Smithsonian Center for Astrophysics

April 24, 1997

CAMBRIDGE, MA -- The notion that giant, Jupiter-like bodies may 
be a common occurrence around stars like the Sun has been 
bolstered by the discovery of such an object orbiting Rho Coronae 
Borealis, a star in the constellation Northern Crown. The newly 
discovered planet offers additional evidence for how such systems 
form, and bolsters the idea that other worlds like our own may be 
widespread throughout the galaxy.

The discovery was made by a team of scientists from three 
institutions -- the Smithsonian Institution's Astrophysical 
Observatory (SAO) in Cambridge, MA, the National Center for 
Atmospheric Research (NCAR) in Boulder, CO, and the Pennsylvania 
State University in State College, PA -- based on observations 
made at the Smithsonian's Fred Lawrence Whipple Observatory on 
Mt. Hopkins, Arizona.

The scientific team includes Sylvain Korzennik, Martin 
Krockenberger, Peter Nisenson, and Robert Noyes of SAO; Harvard 
University graduate student Saurabh Jha; Timothy Brown and Edward 
Kennelly of NCAR; and Scott Horner of Penn State.

Using a special instrument known as the Advanced Fiber Optic 
Echelle (AFOE) spectrograph located at the 1.5-meter Tillinghast 
Reflector of the Whipple Observatory, the scientists detected 
extremely small variations in the recession velocity of Rho 
Coronae Borealis that are thought to be caused by the presence of 
an orbiting companion.

With the AFOE capable of measuring velocity variations smaller 
than 10 meters per second (about 22 miles per hour), the 
scientists found that the speed of Rho Coronae Borealis varied 
back and forth by about 67 meters per second, or 150 miles per 
hour, over a 40-day period. This led the team to conclude that 
the star has a companion in a 40-day orbit and, from the size of 
the velocity variation and the mass of the star (almost identical 
to the Sun), they calculated that the companion must be slightly 
more massive than the planet Jupiter.

The short orbital period means the planet must lie only about 1/4 
of an Astronomical Unit from the star -- closer than Mercury 
orbits the Sun (an AU is the distance of the Earth from the Sun). 
This also implies its temperature would be about 300 degrees C, 
or more than 500 degrees F -- much too hot for liquid water to 
exist, and hence not a likely place for life to form.

According to the researchers, the circular nature of the orbit 
suggests that the planet was formed like the planets in our own 
solar system, that is, through the slow coalescence of dust and 
gas from the circularly rotating disk that is thought to surround 
all newborn stars. A more eccentric, or highly elliptical orbit, 
could imply that the companion object was a failed star, the 
unsuccessful second partner in a potential binary star system.

"This discovery helps show that giant planets like Jupiter may be 
reasonably common around ordinary stars," says Robert Noyes of 
SAO. "Moreover, they can be found at a variety of distances from 
their parent stars, ranging from very close in, like the 
companion to 51 Pegasi, to very far away, like Jupiter relative 
to the Sun. The planet around Rho Coronae Borealis, like several 
others, is in between.

"It is exciting to think that there may be many smaller planets 
much more like the Earth in orbit around these stars, as in our 
own Solar System," says Noyes.

Timothy Brown, of NCAR, carried out the design and fabrication of 
the AFOE spectrograph's optics. He added, "All the giant planets 
found so far orbit Sun-like stars. The star Rho Coronae Borealis 
is another one of these, but it appears to be about 10 billion 
years old -- twice as old as the Sun."

Scott Horner, of Penn State, designed and built the AFOE's iodine 
cell (a precise velocity-reference device). "It was the star's 
solar similarity that led us to target it for study in the first 
place," he agreed. "Soon after we began to look at it, we thought 
that its radial velocity was varying. Now, after 11 months of 
monitoring, we're sure."

As one of the stars forming the "crown" of the constellation, Rho 
Coronae Borealis is visible from February through September to 
naked-eye observers in the Northern Hemisphere . It is about 50 
light years from Earth.

A scientific paper describing the discovery has been accepted for 
publication in the Astrophysical Journal Letters. A pre-
publication version of the paper has also been made available, 
along with other details about the AFOE program, on the World-
Wide Web at http://cfa-www.harvard.edu/afoe.  NCAR is sponsored 
by the National Science Foundation.

For more information, contact:

James Cornell, Public Affairs, SAO -- 617-495-7462;
jcornell@cfa.harvard.edu

Anatta, Public Affairs, NCAR --303-497-8604;
anatta@ucar.edu

Barbara Kennedy, College Communications, Penn State -- 814-863-
4682; bkk1@psu.edu

Figure available upon request from SAO Public Affairs, 617-495-
7461; or, as an anonymous ftp at: ftp://cfa-
ftp.harvard.edu/pub/afoe/np.ps

Caption:
Graphic representation of variations in the velocity of the star 
Rho Coronae Borealis observed at the Smithsonian Institution's 
Whipple Observatory in Arizona, showing a 40-day period 
indicative of a Jupiter-sized companion.
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SHUTTLE EXPERIMENT TO STUDY MEDICINAL PROPERTIES OF PLANTS
NASA release:  97-62

April 1, 1997

Studies of plants on the next Space Shuttle mission may someday 
lead to the production of life- saving medicines and other 
important compounds.

The experiments conducted by Dr. Gerard Heyenga at NASA's Ames 
Research Center, Mountain View, CA, will be part of the 16-day 
STS-83 mission, scheduled for launch this week.

"A fundamental objective of this research is to evaluate whether 
microgravity may be used to alter specific metabolic pathways in 
plants, and ultimately apply this technology for Earth-based 
benefits," Heyenga said.

Heyenga hypothesizes that extended exposure of plants to 
microgravity may reduce their expenditure of energy on structural 
components, thereby increasing flow through other metabolic 
pathways, many of which produce materials of important medicinal 
value.  Of even greater significance is the possibility that 
corresponding changes may occur at a genetic level, he said.

A comparison between space- and Earth-grown plants would give a 
unique opportunity to obtain a greater understanding of how these 
pathways are controlled at the gene level, Heyenga said.  In 
turn, "such knowledge would allow us to manipulate or genetically 
engineer plants with desired metabolic traits," he added. "For 
example, this information could be applied to the lumber industry 
in the production of trees with a low lignin content, greatly 
reducing the cost of paper production both economically and 
environmentally." Conversely, it might be applied to improving 
timber quality in fast-growing softwoods, reducing the need to 
harvest slow-growing hardwoods, he said.  "If this hypothesis is 
correct and achievable, it obviously represents the basis for a 
multi-billion dollar industry and certainly highlights the value 
of space-related research and such facilities as the Space 
Station."

A critical requirement in the investigation is the ability to 
maintain well-characterized and high- quality plant-growth 
conditions during space flight and corresponding Earth 
experiments.  "To achieve a meaningful understanding of the 
effects of microgravity on plants, it is essential that we 
minimize or avoid additional factors that may cause any stress 
and that complicate the evaluation," Heyenga said.

To this end, the flight experiment will involve the use of a new, 
advanced plant growth facility known as the Plant Generic 
Bioprocessing Apparatus (PGBA), built by BioServe, a NASA 
Commercial Space Center located at the University of Colorado in 
Boulder.  The chamber was first flown on the Space Shuttle in 
1996.  "While it was essentially a hardware verification test, 
the PGBA produced a particularly high quality of plant material 
over the ten-day mission, which provided a good basis for further 
research," Heyenga said.

The PGBA chamber maintains a highly controlled environment, 
supplying appropriate light, temperature and gas exchange 
conditions.  The chamber will utilize the new modular "nutrient 
pack system" designed by Heyenga to supply plants with water and 
nutrients throughout the mission.  Thirty packs will be used to 
support the growth of nine plant species.

The packs offer several advantages over existing systems.  
Depending on the type of supporting substrate used, packs may 
reabsorb water from the chamber's condensate recovery system, 
closing the water loop and presenting an important opportunity 
for long-term plant cultivation.  A number of packs will utilize 
a gel matrix that will allow the examination of the roots' 
spatial orientation.  Since the matrix is safely encapsulated in 
a protective membrane, the nutrient pack system has been 
certified for the first radiolabelling tracing experiment of 
higher plants in space.  "This technology will open an entirely 
new area of space plant physiology, allowing the study of issues 
not previously possible," Heyenga said.  "It is likely to lead to 
some very exciting results."

The plant species chosen for the flight experiment include a 
member of the black pepper family.  This choice was based on a 
collaborative effort with a research group in Brazil.  "I believe 
it is highly important that we utilize every possible means to 
expand our understanding in space research," Heyenga said.  "The 
use of such tropical species, with their unique and specific 
metabolic pathways, hopefully will provide us with an early 
indicator of whether our hypothesis is correct while the plants 
are exposed to the relatively short period of microgravity 
experienced during a typical Space Shuttle mission."

Despite the complexity of the research program, Heyenga is 
pleased with progress so far.  "The work has involved a 
particularly broad multidisciplinary effort by a number of 
organizations.  As a visiting scientist on a National Research 
Council fellowship, it is unique to find a place like Ames that 
can support this type of activity," he said.  "Earlier work by 
Dr. Robert MacElroy and Dr. Mark Kliss at Ames in the area of 
enclosed plant growth systems has provided important support for 
the present flight experiment."
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NASA'S STARDUST TEAM STUDIES HALE-BOPP'S COMETARY COUSIN
JPL release

April 3, 1997

Just as Comet Hale-Bopp continues its journey across the 
nighttime sky, another currently visible comet, Wild 2, is 
capturing the attention of NASA's Stardust Project for a vitally 
important reason.

Stardust, a spacecraft with a planned 1999 launch, will capture 
samples of comet dust from Wild 2 in 2004 for return to Earth in 
2006.  This current appearance by Wild 2 (pronounced "Vilt 2"), 
offers the Stardust team a prime opportunity to prepare for the 
spacecraft's historic journey by gathering data on the comet's 
brightness and the size and quantity of its gas and dust 
particles.

The spacecraft is protected from oncoming cometary particles with 
a front "Whipple Bumper," a shield named for renowned astronomer 
Fred Whipple, with a composite structure that includes metals and 
several curtains of the same material as bullet-proof vests.  
However, the bumper does not offer unlimited protection against a 
barrage of numerous, large particles.

"We want to study the dust envelope of Wild 2 so we'll know how 
close we can fly without jeopardizing the spacecraft," said 
Stardust Project Manager Dr. Kenneth Atkins. "These current 
observations will help us significantly reduce the risk."

By observing Wild 2 in both visible and infrared light, the 
Stardust team will be able to fine-tune models of the comet 
environment and mission logistics.  Final trajectory adjustments 
may be made up to a few hours before encounter, using 
observations made by Stardust en route to Wild 2.  That encounter 
will take place on January 2, 2004, about 98 days after the 
comet's perihelion, or closest pass by the Sun. During Wild 2's 
current visit, scientists will study the comet's activity at a 
comparable post-perihelion point, gathering data crucial to the 
success of the Stardust mission.

Wild-2 studies are being conducted at numerous observatories, 
including Lowell Observatory, Flagstaff, AZ; the Lunar and 
Planetary Laboratory, University of Arizona, Tucson; the W.M. 
Keck Observatory and other major telescopes atop Mauna Kea, HI; 
and the 200-inch Hale telescope at Palomar Observatory near San 
Diego, CA.  Amateur astronomers can see Comet Wild 2 with a 
relatively small telescope through August, with the best viewing 
before the end of May.  With an apparent magnitude of 9.6, Wild 2 
is currently visible almost directly overhead about one hour 
after sunset and is located in the constellation of Cancer close 
to the Praesepe open star cluster.

Comet Wild 2, a short-period comet with a six-year orbit, was 
discovered in 1978 by the Swiss astronomer Paul Wild, after its 
close encounter with Jupiter in 1974.  This may have been the 
comet's first journey to the inner solar system in recent 
centuries, which means it is in a more pristine state than other 
comets which have been "around the block" more often.  For this 
and several other reasons, Wild 2 was chosen as the destination 
comet for Stardust.

As Atkins explained, "Wild 2's orbit presents attractive features 
for doing a sample return.  The comet will be in the right place 
at the right time so that when Stardust encounters it, Wild 2 
will have a relatively low flyby speed of 6 kilometers per second 
(3.7 miles).  This makes the task of catching the comet dust as 
it whizzes by much easier.  In addition, the orbital geometry of 
Wild 2 enables us to save money by launching Stardust on a Delta 
rocket and designing an efficient trajectory."

To capture the comet dust without harming it, Stardust will use 
aerogel, a spongy, silica-based solid with 99 percent empty 
space.  The tiny cometary particles will bury themselves in the 
transparent aerogel, awaiting retrieval by scientists on Earth.  
On its way to Wild 2, Stardust will loop twice around the Sun and 
collect interstellar dust particles.  By returning these space 
and cometary materials to Earth, Stardust will mark the first 
space sample return mission since the Apollo missions collected 
moon rocks in the 1960s and 1970s.

Stardust co-investigator Ray Newburn said comets are apparent 
leftovers from the formation of the solar system and may unlock 
many cosmic secrets.  As he put it, "Comets are a different sort 
of beast.  They've been in a cosmic deep-freeze for most of the 
solar system's 5-billion-year history.  Many scientists believe 
comets added complex organic molecules to the primordial soup of 
oceans that helped form life. Stardust should give us some hard 
facts about Wild 2 and other comets, including chemical 
composition and age."

Stardust is one of NASA's Discovery missions, which team the 
agency with industry and universities to launch low-cost 
spacecraft in a short time frame with highly-focused science 
goals.  Stardust's principal investigator is Dr. Don Brownlee of 
the University of Washington, Seattle, WA.

The Stardust spacecraft and sample return capsule are being built 
by Lockheed Martin Astronautics in Denver, CO.  The mission is 
managed by NASA's Jet Propulsion Laboratory for NASA's Office of 
Space Science, Washington, DC.  JPL is also developing the 
aerogel and the spacecraft's navigational camera, also to be used 
for scientific imaging.  Stardust's cometary and interstellar 
dust analyzer instrument is provided by Jochen Kissel through the 
Max Planck Institute in Germany; the University of Chicago, IL, 
is building a Whipple Shield dust impact counter.

Additional information is available on the Stardust home page on 
the World Wide Web at:
http://pdc.jpl.nasa.gov/stardust/home.html.
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NASA REVISES INTERNATIONAL SPACE STATION SCHEDULE
NASA release:  97-65

April 9, 1997

NASA will begin its on-orbit assembly of the International Space 
Station (ISS) no later than October 1998, and is looking at 
options that will allow the Agency to work around the delay 
caused by the late arrival of a key station module.

"We knew from the outset that building an International Space 
Station was going to be tremendously challenging.  Space 
exploration is not easy or predictable," said NASA Administrator 
Daniel S. Goldin.  "We will work through this schedule issue, and 
we undoubtedly will face additional problems in the future.  But 
we are well on our way to the realization of this world-class 
facility," he said.

The on-orbit assembly of the International Space Station 
originally was scheduled to begin in November 1997 with the 
launch of the NASA-financed/Russian-built and launched Functional 
Cargo Block (FGB).  Inadequate funding by the Russian government 
to the Russian Space Agency (RSA) and its contractors for 
building another key station element -- the Service Module (SM) -
- has put construction up to eight months behind schedule.

NASA managers and engineers have been reviewing various options 
to mitigate the impact to the ISS program of the current schedule 
slip of the Service Module, and to begin the steps necessary to 
mitigate the impact of potential additional Russian delays.  RSA 
has been a joint participant in the effort to identify these 
steps.  Options under consideration are:

-Modify the FGB to allow for on-orbit refueling and upgrade of 
its avionics capability.  These changes will give the FGB the 
capability to augment the early control and reboost capabilities 
to protect for a Service Module delay.

-Develop an Interim Control Module (ICM) in conjunction with the 
Naval Research Laboratory to provide reboost capability and 
attitude control in the event that the SM experiences further 
delays, or propellant storage/reboost capability if the SM is 
launched on time.

-Consider the installation of life support systems in the U.S.  
lab to allow early human presence on the ISS.

-Define options involving the ICM to provide the functions of a 
permanent propulsion module in order to complement Russian 
logistics capability and to provide roll control to replace or 
complement the Russian Science Power Platform functions.

NASA will determine the timing for decisions which need to be 
made in the event that Russia is unable to provide its agreed 
contributions to the ISS program.  These decision points will be 
selected to allow for the timely provision of an alternative 
capability.

NASA has begun initial steps at the working level to accommodate 
changes to the Space Shuttle manifest.  NASA has reassigned the 
Space Shuttle Endeavour to fly the September 1997 STS-86 mission 
to the Mir space station instead of the Space Shuttle Atlantis.  
This change will allow Atlantis to begin its scheduled orbiter 
maintenance down period several months earlier, while permitting 
Endeavour a mission prior to flying the first ISS assembly flight 
in July 1998.

Additional adjustments to the remainder of the assembly sequence 
will be worked in consultation with the other International 
Partners and research community over the next several weeks.
-----------------------------------------------------------------

NASA EXPLAINS HOW MOLECULAR-SIZED GEARS MIGHT WORK
NASA release:  97-75

April 21, 1997

A technical paper sponsored by NASA and recently accepted by the 
journal "Nanotechnology" explains how molecular-sized gears might 
work.

"Thanks to simulation of molecular-sized gears by a NASA 
supercomputer, hope is growing that products made of thousands of 
tiny machines that could self-repair or adapt to the environment 
can ultimately be constructed," said Al Globus, a co-author of 
the paper.

Authors are Jie Han, Al Globus, Richard Jaffe and Glenn Deardorff 
of NASA's Ames Research Center, Mountain View, CA.

Researchers have simulated attaching benzyne molecules to the 
outside of a nanotube to form gear teeth, explained Globus.  
Nanotubes are molecular-sized pipes made of carbon atoms.  "You 
also need a cooling system for gears.  We used a supercomputer to 
simulate successful cooling of molecular-sized gears with helium 
and neon gases," he explained.

To "drive" the gears, the computer simulated a laser that served 
as a motor.  "The laser creates an electric field around the 
nanotube.  We put a positively charged atom on one side of the 
nanotube, and a negatively charged atom on the other side.  The 
electric field drags the nanotube around like a shaft turning," 
he said.

"These gears would rotate best at about 100 billion turns per 
second or six trillion rotations per minute (rpm)," he added.  
The gears that Globus and others have simulated with computers 
would be about a nanometer across.  A nanometer is one-billionth 
of a meter.

One practical use of nanotechnology would be to build a "matter 
compiler," said Creon Levit, a Globus colleague at Ames.  "We 
would give this machine, made of nano parts, some raw materials, 
like natural gas, for example.  A computer program would specify 
an arrangement of atoms, and the matter compiler would arrange 
the atoms from the raw materials to make a macro- scale machine 
or parts," Levit added.

"A matter compiler is not just science fiction.  In the 
biotechnology industry, there are already 'peptide synthesizers' 
in use.  You give them a sequence of amino acids you want 
produced, and the machine will create those peptides.  But you 
can't make rockets out of peptides," he said.  A peptide is a 
sequence of amino acids.

"A step along the way to make an aerospace matter compiler is an 
even smaller hypothetical machine, the 'assembler/replicator,'" 
said Globus.  "The replicator can make a copy of itself, just as 
a living cell can duplicate itself.

"We would like to write computer programs that would enable 
assembler/replicators to make aerospace materials, parts and 
machines in atomic detail," he said.  "Such materials should have 
tremendous strength and thermal properties." Further information 
on these materials can be obtained on the researchers' Internet 
page at URL:
http://www.nas.nasa.gov/nanotechnology.

An image of the nanogear from a computer simulation is available 
at the following URL:
http://ccf.arc.nasa.gov/dx/basket/storiesetc/Nanopix.html

A long range goal, according to Globus, is to make materials that 
have radically superior strength-to-weight ratio.  Diamond, for 
example, has 69 times the strength-to-weight ratio of titanium.  
A second goal is to make "active" or "smart" materials.

"There is absolutely no question that active materials can be 
made," Globus explained.  "Look at your skin.  It repairs itself.  
It sweats to cool itself.  It stretches as it grows.  It's an 
active material," he said.

Globus strongly emphasized that making real nanomachines may be 
decades away, but he said that computer simulations suggest the 
tiny machines are possible after engineers learn to build 
nanoparts and to assemble nanomachines.

The nanogear and other related Ames research is a collaboration 
between the Ames Numerical Aerospace Simulation Systems Division 
and the Ames Computational Chemistry Branch.
-----------------------------------------------------------------

CHRONOLOGY OF LUNAR AND PLANETARY EXPLORATION AVAILABLE

NSSDC has made available a Chronology of Lunar and Planetary 
Exploration on the Web at:
http://nssdc.gsfc.nasa.gov/planetary/chrono.html

The chronology is in the form of a timeline, with information on 
all lunar and planetary missions attempted, successfully or 
unsucessfully, by all countries over the last 40 years.  Links 
lead to more detailed descriptions and information on each 
spacecraft and mission from the NSSDC Master Catalog.

If you wish further information about this or other planetary 
information and data available at NSSDC, please contact Dr. David 
R. Williams (dwilliam@nssdc.gsfc.nasa.gov).
-----------------------------------------------------------------

MICROGRAVITY SCIENCE LABORATORY MISSION SET FOR JULY; REMAINING 
1997 SHUTTLE MANIFEST ADJUSTED SLIGHTLY
NASA release:  97-81

April 25, 1997

Columbia's Microgravity Science Laboratory (MSL) mission will fly 
again in early July to complete the mission cut short earlier 
this month because of a fuel cell problem.  The remaining Space 
Shuttle flights in 1997 have been adjusted to accommodate 
Columbia's mission, which will fly as STS-94.  Air Force Lt. Col.  
Jim Halsell and the rest of the STS-83 crew will fly this mission 
and will conduct proficiency training until the flight.

Space Shuttle Program managers today formally baselined the STS-
94 mission to follow Atlantis' sixth docking with the Russian 
space station Mir next month.  Astronaut
Jerry Linenger will return home on STS-84 following a four-month 
stay on Mir, and Mike Foale will replace him as a station crew 
member.  Managers will formally select the launch date following 
the Flight Readiness Review on April 30.

"While shortening STS-83 was disappointing, we now are in a 
position to do everything possible to complete the MSL mission 
with minimal impact to downstream flights," said Space Shuttle 
Program Manager Tommy Holloway.  "Also, it provides us with a 
unique opportunity to demonstrate our ability to respond to 
challenges such as this one."

Reflying Columbia in July dictated that downstream flights for 
the remainder of the year change slightly.  Following STS-94, 
Discovery will fly in early- to mid-August on the STS-85 mission 
to deploy and retrieve a science satellite to study Earth's 
atmosphere.  The flight also will demonstrate the use and 
operational capability of a robot arm that will be deployed 
outside the Japanese Experiment Module of the International Space 
Station.

The seventh Shuttle-Mir docking mission on Atlantis is targeted 
for mid- to late-September.  STS-86 will include the return of 
Foale from Mir and delivery of his replacement, astronaut Wendy 
Lawrence.

The eighth and final mission scheduled in 1997 will be the STS-87 
flight of Columbia slated for mid- to late-November.  The 16-day 
mission includes the conduct of science experiments associated 
with the fourth flight of the U.S. Microgravity Payload and the 
deployment and retrieval of a science satellite.
-----------------------------------------------------------------

STUDENT WINNERS TO BE HONORED IN WASHINGTON, DC
NASA release:  97-84

April 29, 1997

Twenty-seven students from public and private schools across the 
United States have won national recognition in NASA's 17th annual 
Space Science Student Involvement Program competition.  The 
students will be honored along with their teachers at the 
National Space Science Symposium, May 3-7, at the Marriott Hotel 
at Metro Center, 775 12th St., NW, Washington, DC.

The competition, co-sponsored by NASA and the National Science 
Teachers Association, is an interdisciplinary program designed to 
address the need for greater literacy in the areas of science, 
critical and creative thinking, mathematics and technology.  Over 
10,000 students in elementary, junior high, and high school 
competed in five competition categories using their skills in 
mathematics, science, technology, art and creative writing.

The National Space Science Symposium brings together the 27 
national winners and their teachers to recognize their academic 
achievement in an environment designed to further challenge their 
talents.  The trip to the symposium includes formal presentations 
of their entries by the students.

In addition to their recognition in Washington, other awards 
include opportunities to intern at a NASA field center for a week 
during the summer, Space Camp scholarships, medals, ribbons and 
certificates.  Winners of the Interplanetary Art competition will 
have their artwork displayed at the Marriott Metro Center Hotel 
during the symposium.  Interested persons can view the display in 
Salons A, B and C through Tuesday, May 6.  After the symposium, 
artwork will be on display in museums, schools and other public 
sites throughout this year.

On Monday, May 5, all events will be open to the press.  
Beginning at 8:30 a.m. EDT, the national winners of four of the 
competitions will present their winning proposals in Salons A,B 
and C.  At 1 p.m., eight national semi-finalist high school 
student winners will present proposals for a Mars science 
experiment project to a panel of scientists.  On Tuesday, May 6, 
students will tour the Capitol and meet their members of 
Congress.

At 6:30 p.m. on May 6, the students and their teachers will be 
honored at a banquet at the Marriott Metro Center Hotel.  The 
banquet speaker will be Dr. Robert Parker, a former astronaut who 
is currently Director, Space Operations Utilization Program, 
Office of Space Flight, NASA Headquarters, Washington, DC.

Following is the list of competitions and winners.

Mars Science Experiment

Students in grades 9 -12 planned and developed a trip to Mars and 
proposed an experiment to be conducted along the way.  Students 
were required to follow scientific research guidelines when 
designing the study.  The following regional winners will compete 
for first place during the Symposium:

  Faisal Reza, Bronx High School of Science, Bronx, NY   Marja 
Matthews, Anacostia High School, Washington, DC   Elisabeth 
Grove, North Carolina School of Science and Mathematics, Durham, 
NC
  Mark Adams, Brussels American School, Brussels, Belgium   Greg 
Hammel, Appleton East High School, Appleton, WI   Katie Griffin, 
Shawnee Mission High School, Overland Park, KS
  Andrew Wong, Diamond Bar High School, Diamond Bar, CA   Amy 
Frost, Laramie High School, Laramie, WY

Interplanetary Art Competition

Students in grades 3 - 12 expressed their talents in science and 
art by creating a two-dimensional illustration depicting a scene 
from interplanetary space and writing an essay describing the 
picture.  The art work will be displayed for public viewing.

  Crystal Reiff, McCray-Dewey School, Troy, IL
  Aja Gibson, Southern Regional Middle School, Manahawkin, NJ   
Ariel Overstreet, Big Timber Grade School, Big Timber, MT

Future Aircraft/Spacecraft Design Competition

Students in grades 3 - 5 worked in teams to design a futuristic 
aircraft or spacecraft.  The students created three illustrations 
and wrote an essay describing the spacecraft.    Taylor Gray, 
Lindsay Hauge, Amber Overstreet, Big Timber Grade School, Big 
Timber, MT

Mission To Planet Earth

Students in grades 6 - 8, worked in three-person teams to create 
an interdisciplinary project using satellites to study the 
effects of human activity on the Earth's ecosystem.  They used 
research methods and an understanding of technology to search for 
solutions to society's ecological problems.

*Steve Gold, Evan Volkman, Jonathan Jaffe, Michael Haendler, Bi-
Cultural Day School, Stamford, CT

Aerospace Internship Competitions

Students in grades 9 - 12 competed for a one-week internship with 
their teacher/advisor at a NASA facility.  Students were chosen 
on the basis of a written proposal of an experiment that could 
theoretically be performed at one of the facilities.

Supercomputer Internship
* Tomoya Ohno, Montgomery Blair H.S., Silver Spring, MD, will 
intern at NASA's Ames Research Center, Mountain View, CA, with 
scientists and engineers working on a Cray Computer.

Space Station Internship
* Maureen Morgan, Parma Senior H.S., Parma, OH, will intern at 
NASA's Johnson Space Center, Houston, TX, with scientists and 
engineers working on the Space Station.

Wind Tunnel Internship
* Leslie Shope, Montgomery Blair H.S., Silver Spring, MD, will 
intern at NASA's Langley Research Center, Hampton, VA, with 
scientists and engineers conducting research in aerodynamics 
using wind tunnels.

Microgravity Internship
* Eric Shang, Montgomery Blair H.S., Silver Spring, MD, will 
intern at NASA's Lewis Research Center, Cleveland, OH, with 
scientists performing microgravity experiments in a drop tube.

Spacelab Internship
* Anne Lee, Montgomery Blair H.S., Silver Spring, MD, will intern 
at NASA's Marshall Space Flight Center, Huntsville, AL, 
conducting experiments with scientists and engineers in the 
pressurized Spacelab module.

Space Telerobotics Internship
* Eric Schewe, Montgomery Blair H.S., Silver Spring, MD, will 
intern at NASA's Jet Propulsion Laboratory, Pasadena, CA, and 
work with engineers conducting research in the microrover 
laboratory for lunar and planetary surface exploration.

Space Astronomy Internship
* Mary Dombrowski, Glastonbury H.S., Glastonbury, CT, will intern 
at NASA's Goddard Space Flight Center, Greenbelt, MD, and work 
with astronomers conducting research in observational and 
theoretical astronomy and solar physics.

Launch Operations
* Christine Hwang, Montgomery Blair H.S., Silver Spring, MD, will 
intern at NASA's Kennedy Space Center, FL, and work with 
engineers on launch operations.

Atmospheric Flight Internship
* Jai Xu, Montgomery Blair H.S., Silver Spring, MD, will intern 
at NASA's Dryden Flight Research Center, and work with engineers 
on flight research programs.
-----------------------------------------------------------------

NASA AWARDS 36 MICROGRAVITY RESEARCH GRANTS
NASA release: 97-86

May 1, 1997

NASA has selected 36 researchers from 19 states and the District 
of Columbia to receive four-year grants worth $2.8 million for 
microgravity biotechnology research.

This ground-based research will continue to build the foundation 
for research on the Space Shuttle and International Space 
Station.

Sponsored by NASA's Human Exploration and Development of Space 
Enterprise, through the Office of Life and Microgravity Science 
and Applications in Washington, DC, and managed by the 
Microgravity Research Program at the Marshall Space Flight Center 
in Huntsville, AL, this research is aimed at improving the 
understanding of physical and chemical processes in the areas of 
protein crystal growth, cell science and fundamental 
biotechnology.

This selection adds to the 49 researchers already associated with 
the program managed by Marshall.  Involved in microgravity 
biotechnology research since the early 1970s, Marshall 
administers the national microgravity biotechnology effort, 
providing the scientific, technical and management expertise to 
successfully conduct spaceflight research.

Ronald F. Porter, manager of NASA's Biotechnology Program at 
Marshall, said "Researchers selected for funding will have NASA's 
microgravity research facilities -- drop-tubes, drop-towers, and 
aircraft flying parabolic trajectories -- at their disposal.  
Their work may eventually lead to flight experiments in space."

A number of the studies involve cellular growth, a key field that 
is fundamental to medical science.  To support cell science, 
researchers can simulate the microgravity conditions of space in 
NASA's bioreactor, using rotation to suspend cell cultures in a 
growth medium.  This technique -- successfully used to study 
cancer growth -- improves our ability to grow cells and tissues 
outside the human body.  Some researchers believe the best 
environment for growing cells is in space, where the lack of 
gravitational effects makes it easier to maintain a suspension of 
growing cells.  NASA's Johnson Space Center, Houston, TX, leads 
the support of cellular growth studies for Marshall.

Protein crystal growth research supported by NASA has important 
applications in medicine, drug design and agriculture.  Proteins 
are complex biochemicals that serve a variety of purposes in 
living organisms.  Crystallized proteins allow scientists to 
learn the molecular structure of proteins.  Determining that 
structure will lead to a greater understanding of how organisms 
function.  Knowledge of the structure also helps the 
pharmaceutical industry develop disease-fighting drugs.

NASA received 130 proposals in response to its microgravity 
biotechnology research announcement.  These proposals were 
reviewed by scientific and technical experts outside NASA, 
including reviewers associated with the National Institutes of 
Health.

A list of the grant recipients is available on the World Wide Web 
at URL:
ftp://ftp.hq.nasa.gov/pub/pao/pressrel/1997/97-086a.txt
-----------------------------------------------------------------

HUYGENS SPACE PROBE READY TO LEAVE EUROPE
ESA press release

Paris, 12 March 1997

The European Space Agency s Huygens probe is ready to be shipped 
to the Kennedy Space Center. On arrival, it will undergo special 
tests and then be mated with the Cassini Saturn orbiter for 
launch in October 1997 on a Titan IVB/Centaur rocket.

Over the past year, the Huygens probe has been integrated and 
extensively tested at the facilities of Daimler Benz Aerospace 
Dornier Satellitensysteme in Ottobrunn near Munich. It was 
designed and developed for ESA by a European industrial 
consortium led by Aerospatiale (F) as prime contractor.

Background facts about the Cassini Huygens mission 

Huygens is a medium-sized mission of ESA s Horizons 2000 
programme for space science, and a contribution to the joint NASA 
ESA Cassini mission.

Christiaan Huygens discovered Saturn s moon Titan in 1655, and 
the mission named after him aims to land a 343 kilogram probe on 
Titan carrying a package of scientific instruments through the 
atmosphere. Six sets of instruments will analyse the chemical 
composition of the atmosphere, observe the weather and topography 
of Titan, and examine the nature of its surface.

Titan is larger than the planet Mercury, and its unique 
atmosphere, rich in nitrogen and hydrocarbons, may resemble the 
atmosphere of the primitive Earth, before life began.

Nominal dates for the Huygens mission are as follows:

* launch, 6 October 1997
* arrival at Saturn, 1 July 2004
* release of Huygens, 6 November 2004
* entry into Titan's atmosphere, 27 November 2004.

The Saturn Orbiter, the other element in the Cassini mission, 
will relay the signals from Huygens to the Earth, before settling 
down to prolonged observations of Saturn and its rings and moons.  
European and American scientists are partners in all the 
experiments, both in the Orbiter and in the Huygens Probe.

Farthest out for Europe

Huygens will travel to a greater distance from the Sun than any 
previous ESA mission, out to the orbit of Saturn at 1400 million 
kilometres, or nearly ten times the Sun Earth distance.  For 
comparison, the farthest ranging mission at present is Ulysses, 
orbiting over the poles of the Sun and out to the orbit of 
Jupiter, 800 million kilometres from the Sun.  As no other 
mission planned or contemplated by ESA at present will go as far 
as Saturn, Huygens is likely to hold the European record for many 
years.
-----------------------------------------------------------------

MARS GLOBAL SURVEYOR FLIGHT STATUS REPORTS
JPL releases

Friday, 21 March 1997

On Wednesday, the flight team transmitted the C6 sequence to 
Surveyor.  This sequence contains commands that will control the 
spacecraft for the next four weeks.  C6 became active on Thursday 
at 6:00 a.m. PST.

The first major event in C6 occurred at 10:00 a.m. PST on 
Thursday.  At that time, the onboard flight computer commanded 
the spacecraft's main rocket engine to fire for six seconds in 
order to make minor corrections to Surveyor's flight path.  
During this trajectory correction maneuver, the main engine 
burned a propellant combination of hydrazine fuel and nitrogen 
tetroxide oxidizer.  In total, the spacecraft expended 
approximately 1.4 kilograms of propellant.

Immediately before the six-second burn was performed, Surveyor 
ignited eight of its 12 attitude-control thrusters for 20 
seconds.  These tiny thruster rockets are normally used to 
stabilize the spacecraft during main engine firings.  The 
initial, 20-second thruster firing settled the liquid in the 
spacecraft's tanks to ensure a smooth flow of propellant to the 
more powerful main rocket engine that was used to perform the 
correction maneuver.

At this time, the navigation team is busy analyzing the accuracy 
of yesterday's trajectory correction maneuver.  However, 
preliminary results from the accelerometer onboard the spacecraft 
show that the engine firing provided a velocity change of 3.875 
meters per second.  This value was within 0.5% of the predicted 
change of 3.857 meters per second.

Yesterday's maneuver was the second in a series of four 
trajectory correction maneuvers that are designed to refine the 
spacecraft's flight path to Mars.  The first maneuver occurred 
shortly after launch last November.  The third and fourth are 
currently scheduled for April 21st and August 25th, respectively.

After a mission elapsed time of 134 days from launch, Surveyor is 
47.69 million kilometers from the Earth, 63.84 million kilometers 
from Mars, and is moving in an orbit around the Sun with a 
velocity of 26.27 kilometers per second.  This orbit will 
intercept Mars on September 12th, 1997.  The spacecraft is 
currently executing the C6 command sequence, and all systems 
continue to be in excellent condition.

Friday, 28 March 1997

No major activities occurred onboard the Mars Global Surveyor 
spacecraft this week.  Meanwhile, at the Jet Propulsion 
Laboratory in Pasadena, Surveyor's navigation team has completed 
their preliminary assessment of the trajectory correction 
maneuver that took place on March 20th.  This short firing of the 
spacecraft's main rocket engine resulted in a velocity change of 
3.875 meters per second and refined Surveyor's flight path to 
Mars.

Initial analysis provided by the navigation team indicates that 
the spacecraft performed the maneuver with an accuracy of greater 
than 99%.  Consequently, the spacecraft is now on a flight path 
that will come within 630 kilometers of the Martian surface at 
the point of closest approach on September 12th.  Additional 
trajectory correction maneuvers scheduled for April 21st and 
August 25th will reduce this approach altitude to 500 and 380 
kilometers, respectively.

After a mission elapsed time of 141 days from launch, Surveyor is 
54.12 million kilometers from the Earth, 58.29 million kilometers 
from Mars, and is moving in an orbit around the Sun with a 
velocity of 25.82 kilometers per second.  This orbit will 
intercept Mars on September 12th, 1997.  The spacecraft is 
currently executing the C6 command sequence, and all systems 
continue to be in excellent condition.

Friday, 18 April 1997

No major mission activities occurred this week onboard the Mars 
Global Surveyor spacecraft.  Back at the Jet Propulsion 
Laboratory in Pasadena, California, the project management has 
made a decision not to attempt any more efforts to free debris 
that is currently keeping the -Y-side solar array slightly out of 
position.  This solar panel is currently deployed and fully 
functional, but is 20.5 degrees from its proper position.

The flight team believes that the position discrepancy was caused 
when a damper shaft in the array's deployment mechanism broke 
shortly after launch.  This damper is a device that was installed 
to minimize the mechanical shock of deployment by slowing the 
motion of the array during deployment.  The flight team theorizes 
that the broken shaft caused the damper arm to wedge into the 
hinge joint connecting the solar panel to the spacecraft.

An important aspect of this position discrepancy is that the 
solar panels will be used at Mars not only to produce electrical 
power, but also to help the spacecraft attain its final mapping 
orbit.  Over the course of a four-month period following Mars 
orbit insertion, Surveyor will be dipped into the upper Martian 
atmosphere on every orbit.  During these atmospheric passes, air 
resistance generated by the solar panels will slow the spacecraft 
and gradually lower its orbit.  Surveyor will use this 
"aerobraking" technique to lower the high point of its orbit from 
an initial 56,000 kilometer altitude to just under 400 
kilometers.

For the last few months, the flight team has been considering 
several options to free the debris and allow the panel to latch 
and lock into its proper position.  One idea involved a short 
firing of Surveyor's main rocket engine to provide a small force 
to dislodge the damper arm.  However, such efforts will not be 
necessary because an extensive analysis has indicated that 
aerobraking with the -Y solar panel slightly out of position is 
feasible with a few minor modifications to the original plan.

One of the minor changes involves rotating the panel into a 
position where the front side will face into the air flow instead 
of the back side.  This orientation will keep the unlatched panel 
from folding up on itself when it encounters the air flow during 
aerobraking.  Because the front side contains the silicon cells 
that produce electricity, it is more fragile than the back side 
and cannot tolerate as much heating from the air flow.  As a 
result, the flight plan will be modified so that Surveyor 
aerobrakes at a slightly slow pace than previously planned.

After a mission elapsed time of 162 days from launch, Surveyor is 
76.20 million kilometers from the Earth, 44.32 million kilometers 
from Mars, and is moving in an orbit around the Sun with a 
velocity of 24.59 kilometers per second.  This orbit will 
intercept Mars 146 days from now, slightly after 6:00 p.m. PDT on 
September 11th (01:00 UTC, September 12th).  The spacecraft is 
currently executing the C6 command sequence, and all systems 
continue to be in excellent condition.

Friday, 2 May 1997

No major activities took place this week.  For the past three 
weeks, few activities have occurred because the Surveyor 
spacecraft has been configured in a quiet state for a search 
campaign to detect gravity waves.  According to theoretical 
physics, these waves are gravitational disturbances emitted by 
all objects in the universe.  However, because gravity is a 
relatively weak force, detection of these waves is almost 
impossible unless they are generated by massive objects such as 
black holes and matter at the center of the Milky Way Galaxy.

To date, nobody has ever detected a gravity wave.  If Surveyor 
encountered these waves, the spacecraft would experience an 
extremely small jolt.  This tiny bumping motion would cause a 
tiny shift in the frequency of the spacecraft's radio signal 
transmitted to Earth.  Analysis of the data generated by this 
experiment will take six months or more.

After a mission elapsed time of 176 days from launch, Surveyor is 
92.74 million kilometers from the Earth, 37.03 million kilometers 
from Mars, and is moving in an orbit around the Sun with a 
velocity of 23.89 kilometers per second.  This orbit will 
intercept Mars 132 days from now, slightly after 6:00 p.m. PDT on 
September 11th (01:00 UTC, September 12th).  The spacecraft is 
currently executing the C7 command sequence, and all systems 
continue to be in excellent condition.

Status report prepared by:

Office of the Flight Operations Manager
Mars Surveyor Operations Project
NASA Jet Propulsion Laboratory
California Institute of Technology
Pasadena, CA 91109
-----------------------------------------------------------------

End Marsbugs, Vol. 4, No. 6.

