MARSBUGS:  
The Electronic Exobiology Newsletter
Volume 5, Number 14, 28 May 1998.

Editors:

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

Julian Hiscox, Division of Molecular Biology, IAH Compton 
Laboratory, Berkshire, RG20 7NN, UK.  Julian.Hiscox@bbsrc.ac.uk or 
Marsbug@msn.com

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.  Article 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 and Word97 files suitable for 
printing may be obtained via anonymous FTP at:  
ftp.uidaho.edu/pub/mmbb/marsbugs.  Also, an official web page is 
under construction.  Currently it is part of 
http://members.aol.com/marsbugs/dave.html (right now, the page 
simply points to the FTP site).

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.


INDEX

1)	MARSHALL SCIENTIST TO PARTICIPATE IN ASTROBIOLOGY INSTITUTE
By Dave Dooling

2)	NASA SELECTS INITIAL MEMBERS OF NEW VIRTUAL ASTROBIOLOGY 
INSTITUTE
NASA release 98-84

3)	POLICIES NEEDED FOR REPORTING POTENTIAL HAZARDS OF ASTEROID 
COLLISIONS WITH EARTH
National Research Council release

4)	SPACEGUARD REVISITED
By Sir Arthur C. Clarke

5)	BIOSPHERE LESSONS CAN BE APPLIED TO SPACE, FORMER CREW CO-
CAPTAIN SAYS
Wake Forest University School of Medicine release

6)	YALE RESEARCHERS SYNTHESIZE ENZYME THAT MAY HAVE PLAYED KEY 
ROLE IN FORMATION OF LIFE
By Vincent Kiernan

7)	MARS SOCIETY FOUNDING CONVENTION

8)	THE MARS MICROPHONE:  READY TO GO
By Greg Delory

9)	1998 MARS SURVEYOR PROJECT STATUS REPORTS
By John McNamee

10)	STARDUST STATUS REPORTS
By Ken Atkins

11)	GALILEO EUROPA MISSION STATUS
JPL release

12)	THIS WEEK ON GALILEO
JPL releases

13)	NEW GALILEO IMAGES OF EUROPA
JPL release



MARSHALL SCIENTIST TO PARTICIPATE IN ASTROBIOLOGY INSTITUTE
By Dave Dooling, MSFC

22 May 1998

[Editor's note:  the photos described here can be seen in the 
Word97 version of Marsbugs or at 
http://science.msfc.nasa.gov/newhome/headlines/ast22may98_1.htm]

What started as a hobby for a scientist here has become a new line 
of scientific investigation in the newly formed NASA Astrobiology 
Institute.  Richard Hoover, a solar physicist at Marshall Space 
Flight Center, is co-investigator on two astrobiology proposals 
that NASA has selected for funding.

[photo caption] The poster depicts Hoover's foray into 
astrobiology, including Europa (background and top), and a 
cyanobacteria (center) found deep in the Antarctic (bottom).  
(links to a 900x1281-pixel, 320K JPG.  Photo credit:  
NASA/Marshall Space Flight Center.)

Dr. David McKay of Johnson Space Center is principal investigator 
on a proposal to look for biomarkers in astromaterials:  signs of 
life in soil, rocks, and other materials from outside the Earth.  
Dr. Kenneth Nealson of the Jet Propulsion Laboratory in Pasadena, 
Calif.  is principal investigator on a proposal on a study of the 
co-evolution of planets and biospheres.  Hoover will be a co-
investigator on both proposals.

"This is really exciting," said Hoover, whose primary work at 
Marshall has been developing advanced telescopes to study the sun.  
"We are going to look at life on Earth in the most extreme 
environmentshot volcanic vents, deep-ocean ice, and even ancient 
rocksand help sharpen our senses when we look for signs of life 
on Mars, Europa, and other astromaterials."

For Hoover, this journey started years ago when he became 
fascinated by diatoms (below), the "living jewels of the sea."  It 
became a hobby, then a passion, which has earned him international 
recognition.  Most recently, he has applied knowledge gained in 
this area to the search for preserved microbes in Antarctic ice 
cores as a model of extraterrestrial life.

While Mars has long been thought of as the best chance for life 
elsewhere in our solar system, recent evidence of liquid water in 
Europa, one of Jupiter's moons, raises the possibility of life 
there.  In turn, the discoveries over the past few decades of life 
in hot springs, deep ocean vents, and even Antarctic ice broaden 
the range of conditions where at least basic life forms may set up 
housekeeping.

In the first investigation, Hoover will work with David McKay who 
startled the scientific community in 1996 with claims that he had 
found evidence of microbial fossils in a rock believed to have 
fallen to Earth from Mars.  While the evidence within the Allan 
Hills meteorite, ALH84001, continues to be debated, pictures and 
data from the Mars Pathfinder and Mars Global Surveyor missions 
have added evidence that Mars once had flowing water.

"The primary research that we'll be doing is looking microfossils 
in ancient rocks," Hoover said.  He anticipates analyzing 
phosphorites from Mongolia, oil shale from Siberia, and other 
formations dating back about 3.8 billion years.  The search for 
fossils of bacteria and archaea will be of prime importance.

[photo caption] Left:  Europa, as seen by the Galileo spacecraft, 
is covered with ice, apparently atop a world ocean, raising the 
possibility that conditions could be right for lifeand similar to 
those in Lake Vostok, hidden under 3 km (1.8 mi) of Antarctic ice 
(right).

Life is divided into three principal domains, eukaryotes (large 
cells, like plants and animals), bacteria, and archaea.  Archaea, 
only discovered in 1977, normally thrive in extreme conditions 
like the hot springs of Yellowstone National Park, thermal vents 
deep underwater in the mid-Atlantic ridge, highly acid and 
alkaline baths, and deep rocks.  These are not normal conditions 
now, but were more than 3 billion years ago.

"It's now looking like the archaea are among the most ancient 
forms of life on Earth," Hoover said.  And the implication is that 
if life could originate and then thrive under such conditions 
here, then it could do the same on Mars and Europaperhaps even 
volcanic Iowhere conditions are considered inhospitable.

Under the biosphere evolution study with Nealson at JPL, Hoover 
will develop methods to fix, prepare, and view samples so that 
unambiguous indications of lifeor non-lifecan be obtained.  He 
will use advanced tools such as the Scanning Electron Microscope 
(ESEM) and an atomic-force microscope that NASA/Marshall already 
has for engineering work.

"One of the things that's important in preparation techniques is 
making sure that you get no interference from the substrate in the 
X-ray spectral analysis," Hoover said.  NASA/Marshall's ESEM is 
especially good at analyzing biological materials without the need 
for special coatings.  The detail revealed by the ESEM offers new 
challenges.  

[photo caption] Samples of microbes found by the ESEM in deep ice 
from the Antarctic.

"The most critical thing is getting to the ability to recognize 
different types of microorganisms in tools such as the ESEM," 
Hoover said.  "It's a very powerful tool, but it shows you things 
that you don't see in optical microscopes or conventional electron 
microscopes."  That can mean relearning how to recognize creatures 
that you already know.

Recognizing and classifying microbes and bacterial fossils in this 
manner will be doubly important in a field that has thousands of 
unnamed microbes.  The rule in the international microbiology 
community is that an organism is not named unless it is grown in a 
pure culture and is lodgedphysicallyin a recognized cell bank.

"In many cases, these bugs can't be grown in pure culture," Hoover 
said.  Asking a bacterium from a deep ocean vent to grow in a lab 
culture is like asking a human to breathe a vacuum.  It takes more 
than recreating conditions like water temperatures above boiling 
(intense pressure keeps that water from boiling).  Some creatures 
only survive with certain neighbors, like one bacterium that 
releases methane and another that consumes it.

[photo caption] At right, Hoover and Dr. S. S. Abyzov of Russia's 
Institute of Microbiology use the ESEM to probe deep ice from 
Antarctica for signs of life.  (links to a 1,500x1,082-pixel, 576K 
JPG.  Photo credit:  NASA/Marshall Space Flight Center.)

Another challenge will be recognizing life when you see it.  
Hoover said he was recently stumped by a microsphere with a lot of 
iron.  A colleague told him that it was indeed a bacterium that 
consumes iron sulfateFeSO3to get oxygen.

"That tells me that we have to learn the kinds of things that go 
on inside an electron microscope, and in other tools, with respect 
to microbiology," Hoover said, "because these are the kinds of 
tools we'll take to Mars and Europa when we look for life."

"It's extremely important that we continue to learn and to develop 
an enhanced knowledge of microfossils, and of bacteria, 
eukaryotes, and archaea."


NASA SELECTS INITIAL MEMBERS OF NEW VIRTUAL ASTROBIOLOGY INSTITUTE
NASA release 98-84

19 May 1998

NASA has selected 11 academic and research institutions as the 
initial members of the agency's new Astrobiology Institute, thus 
launching a major component of NASA's Origins Program.

The selected institutions represent the best of 53 uniformly 
first-class proposals submitted, according to NASA officials.  
Given that the institute members will remain at their home 
organizations, the partnership among the members and NASA will be 
carried out primarily via the Internet.  This electronic 'virtual' 
Institute will bring together astrophysicists, biologists, 
chemists, physicists, planetologists and geologists to conduct 
interdisciplinary research on the multifaceted issue of life in 
the Universe and its cosmic implications.  It will also help to 
train young scientists in this emerging field.

"These initial members of NASA's Astrobiology Institute will be at 
the forefront of the increasingly important link between astronomy 
and biology, which has been a fundamental interest of mine for the 
past several years," said NASA Administrator Daniel S. Goldin.  
"The 'office hallways' of this virtual institute will be the fiber 
optic cables of the Next Generation Internet, and the 
groundbreaking research that this group generates will help guide 
our space exploration priorities well into the 21st century."

The selected initial members of the Institute are:

*Universities
Harvard University, Cambridge, MA
University of California, Los Angeles
University of Colorado, Boulder
Arizona State University, Tempe
Pennsylvania State University, University Park

*Research Institutions
Carnegie Institution, Washington, DC
The Scripps Research Institute, La Jolla, CA Woods Hole Marine 
Biological Laboratory, Woods Hole, MA

*NASA Centers
Ames Research Center, Moffett Field, CA
Johnson Space Center, Houston, TX
Jet Propulsion Laboratory, Pasadena, CA

NASA has developed the Origins Program with its Office of Space 
Science to search for signs of life in the Universe, both in our 
Solar System and beyond.  The Astrobiology Institute will foster 
the interdisciplinary research and training necessary for future 
exploration of this theme.  Funding for the Institute will begin 
with $9 million in 1999 and $20 million in 2000.  This total is 
expected to grow as research directions are developed and the 
capabilities of the Next Generation Internet are expanded and 
fully utilized.

The Astrobiology Institute members will conduct a broad range of 
interdisciplinary and synergistic research on topics including:  
the formation of organic compounds important to the origins of 
life, such as from meteorites; the formation and characteristics 
of habitable planets; the emergence of self-replicating systems 
and possible pre-biotic worlds; how the Earth and life have 
influenced each other over time, including the evolution of 
ancient metabolism and the interplay of evolved oxygen; the 
evolution of multicellular organisms and the evolution of complex 
systems in simple animals; organisms in extreme environments such 
as hydrothermal vents; and the identification and development of 
biomarkers to determine terrestrial and extraterrestrial 
biosignatures.

The selection of the members, encompassing academic institutions 
and government labs, was based on a competitive evaluation process 
that began with the release of a Cooperative Agreement 
Announcement in October 1997.  The next solicitation opportunity 
for new members will take place in about a year.

For further information on the Institute and the field of 
astrobiology, see the following Internet site:
http://astrobiology.arc.nasa.gov/

The Institute's director and staff will reside at NASA's Ames 
Research Center, Moffett Field, CA.  NASA Ames will manage the 
Institute's operations for NASA's offices of Space Science, Earth 
Science, and Human Exploration and Development of Space at NASA 
Headquarters in Washington, DC.


POLICIES NEEDED FOR REPORTING POTENTIAL HAZARDS OF ASTEROID 
COLLISIONS WITH EARTH
National Research Council release

13 May 1998

Recent news of a possible asteroid collision with Earth in 2028 
sparked intense scientific and popular interest worldwide.  When 
further data revealed that the asteroid had virtually no chance of 
hitting this planet, the episode prompted the astronomy community 
to re-evaluate how they communicate such information to the 
public.

NASA and astronomers should develop protocols for reporting 
information about asteroids that appear to pose a potential hazard 
to Earth, says a new report from a National Research Council 
committee, which began its work before the recent episode.  These 
protocols will be important because several telescope facilities 
and new instruments now coming into operation will dramatically 
increase the rate by which scientists are able to discover 
asteroids and comets whose orbits approach Earth.  With the flood 
of discoveries expected within the next decade also will come the 
risk of false alarms.

Some 400 Earth-approaching asteroids and comets larger than one 
kilometer in diameter have been discovered so far, but only an 
estimated 10 percent of the objects this size have been 
identified.  Of the thousands that may be discovered, some 
initiallyfor a few days, weeks, or even yearsmay seem likely to 
collide with Earth, until enough data have been collected to 
determine accurate orbits and interpreted to show otherwise.  
Policies for handling such potentially important information will 
be needed.  International scientific organizations, such as the 
International Astronomical Union, could play a role in this task, 
the report says.

Most asteroids orbit the sun in a belt between Jupiter and Mars, 
but thousands have orbits that sometimes take them uncomfortably 
close to Earth.  Geological processes such as erosion tend to 
erase scars left when asteroids and comets occasionally hit Earth, 
but there are some notable exceptions, such as Arizona's Meteor 
Crater.  Moreover, there is evidence that an asteroid or comet 
some five to 10 kilometers in diameter created an enormous crater 
in Yucatan, Mexico, some 65 million years ago.  That event has 
been implicated in the extinction of dinosaurs and other living 
organisms.  This information, coupled with recent evidence of the 
collision of Comet Shoemaker-Levy 9 with Jupiter in 1994, has led 
to increased scientific and public interest in assessing the 
likelihood that a large object might hit Earth again.

Although asteroids and comets are potential hazards to Earth, 
these tiny worlds offer a trove of clues to the solar system's 
birth and early history, the report says.  Exploration of 
asteroids also may be used as stepping stones toward manned 
missions to Mars.  Comets are frozen chunks of ice and dust 
thought to be left from the formation of the planets in the solar 
system.  Asteroids are minor planets, some made from almost pure 
mixtures of nickel and iron like those at the Earth's core or from 
minerals similar to those found in the Earth's crust, and others 
from exotic combinations of carbon compounds.

To better understand the scientific opportunities posed by 
asteroids and comets, the report recommends that priorities be 
given to the following areas:

Telescopic studies.  
NASA, other government agencies, and private research 
organizations should further coordinate their programs using 
ground-based telescopes to search for and study asteroids and 
comets.  Because a typical asteroid or comet is very faint and 
travels by Earth so quickly, the opportunity to view it may last 
no more than a few days or a week at most.  To conduct the 
detailed observations that these fleeting objects require, routine 
or priority access to existing infrared and optical telescopes is 
needed.  Otherwise, telescopes dedicated to characterizing the 
asteroids and comets discovered by ongoing search programs should 
be developed.

Laboratory investigations.  
More research is needed to increase understanding of 
extraterrestrial materials, such as meteorites, which are believed 
to come from asteroids.  Laboratory studies can address, for 
example, the puzzle of how the environment in space changes the 
surfaces of asteroids to such an extent that the physical 
characteristics of the most common varieties of asteroids and 
meteorites do not match.  NASA, other government agencies, and 
private research organizations should support additional 
laboratory investigations of samples of these space-borne objects.  
New analytical instruments, such as those necessary to study very 
small samples of meteorites, also are needed.

Robotic and manned spacecraft missions.  
Spacecraft that pass by, rendezvous with, or obtain samples from 
asteroids orbiting near Earth provide important information on the 
detailed physical characteristics, composition, and geologic 
histories of planetary bodies that is otherwise unobtainable.  
Moreover, Earth-approaching asteroids or comets are among the most 
accessible objects in the solar system.  Indeed, some are easier 
to reach than the moon.  NASA's Galileo missions, for example, 
provided a wealth of information about asteroids Ida and Gaspra 
orbiting between Mars and Jupiter.  Last year, a NASA spacecraft 
made detailed observations of another asteroid, Mathilde.  The 
spacecraft is currently en route to a February 1999 rendezvous 
with Eros, one of the largest Earth-approaching asteroids.  NASA 
should continue such missions and improve spacecraft technology, 
such as propulsion and navigation systems, to allow additional 
low-cost rendezvous and sample-return missions.

Should the United States choose to undertake further manned 
exploration beyond Earth, a strong case can be made for beginning 
with missions to Earth-approaching asteroids, the report says.  
Because missions to these asteroids represent deep-space 
exploration with moderate technical challenges, they would be the 
least-expensive next step in human exploration of space and could 
provide the experience and technology needed for fruitful missions 
to Mars and beyond.  Five percent of Earth-approaching asteroids 
are readily accessible by relatively short space flights.

A primary concern would be keeping the length of the mission as 
short as possible to minimize hazards and risks to which 
astronauts are exposed, including weightlessness, radiation, 
meteoroid impact, and equipment failure.  Further research should 
be conducted to study specific technical requirements necessary 
for a six- to 12-month round-trip expedition.  With the 
anticipated increase in discoveries of Earth-approaching 
asteroids, there likely will be opportunities for missions to one 
or more asteroids each year.

NASA funded the study.  The National Research Council is the 
principal operating agency of the National Academy of Sciences and 
the National Academy of Engineering.  It is a private, non-profit 
institution that provides science advice under a congressional 
charter.  

Copies of The Exploration of Near-Earth Objects are available from 
the National Academy Press for $10.00 (prepaid) plus shipping 
charges of $4.00 for the first copy and $0.50 for each additional 
copy; tel. (202) 334-3313 or 1-800-624-6242.

NOTE:  The report cited in this release is available online at 
http://www.nap.edu/readingroom/enter2.cgi?0309060834.html


SPACEGUARD REVISITED
By Sir Arthur C. Clarke, Kt., CBE
Chancellor, University of Moratuwa, Sri Lanka

26 May 1998

Convocation Address

Less than four years ago, in October 1994, I devoted my 
Convocation Address to something which probably few people had 
ever worried aboutthe danger to our planet of impacts from space.  
Well, during those four years so much has happened that I make no 
apologies for returning to the subject.

If you spend a few hours at night under a perfectly clear sky
which, alas, I haven't done for yearsyou are almost certain to 
see a few meteors sliding silently across the stars; there are 
times, indeed, when you may see hundreds.  One such occasion is 
due in November 1999:  a Space Shuttle launch has been 
rescheduled, and the owners of communications satellites are 
already rushing to take out insurance.  For though that "shining 
furrow", as Tennyson called it, is caused by an object not much 
larger than a pea burning up as it enters the atmosphere, that has 
enough energy to damage, or even destroy, delicate orbiting 
equipment costing hundreds of millions of dollars.  Tennyson, who 
a century and a half ago saw "the heavens filled with commerce" 
could never have imagined that one day this would be literally 
true.

Quite often, one of these cosmic fragments is large enough to 
survive passage through the atmosphere, and falls to earth.  We 
then call it a 'meteorite'; the word 'meteor' applies merely to 
the streak of light across the sky.

That meteorites did fallsometimes in large numbers over 
considerable areashad been known from time immemorial; indeed, it 
has been suggested that they were the only source of iron for 
early man.  Yet two hundred years ago, in what has been called the 
Age of Enlightenment, there was great skepticism about their 
existence.  Thomas Jefferson, widely considered the most brilliant 
President ever to sit in the White House, once remarked after 
hearing that a couple of academic gentlemen had witnessed a shower 
of meteorites:  "I would rather believe that two Yankee professors 
lied, than that stones fell from the sky."  Well, now we know that 
mountains can fall from the sky.

The evidence is overwhelming, yet only in the last few decades has 
this been acceptedas someone once said:  "The obvious we see 
eventually."

Perhaps the best example of this phenomenon is the famous Meteor 
Crater in Arizonaa huge hole in the ground more than a kilometer 
across.  Despite the perfectly accurate name that the locals had 
given to it, for years most geologists argued that the crater was 
homegrownsome kind of volcanic formation! Now we know that it was 
produced by the impact some 50,000 years ago of a nickel-iron mass 
about as large as this building.  Once they removed their mental 
blindfolds, geologists started finding impact craters all over the 
world.  About two hundred have now been identified, and there must 
be many more hidden in the ocean depths.  We live in a very 
dangerous neighborhood:  what has happened countless times in the 
past will, inevitably, occur again in the future.

What did most to focus the attention of the scientificand non-
scientificcommunity on this fact was a paper published in 1980 by 
the American physicist Luis Alvarez and his geologist son Walter, 
suggesting that the extinction of the dinosaurs was linked with 
the impact of an asteroid on Earth, about 65 million years ago*.  

The word 'asteroid' is unfortunate, because it means 'small star'
and asteroids are in fact only small planets, most of them between 
Mars and Jupiter.  The largest, Ceres, is just under a thousand 
kilometers across, but they come in all sizes down to ones that 
would sit comfortably on the Galle Face Green (what there is left 
of it.) So where one draws the line between meteorites and 
asteroids is a matter of definition; they all bits of debris left 
over from the formation of the Solar System.

And so are comets, which are enormously larger but no heavier than 
asteroids, since they are almost entirely clouds of extremely thin 
gas, surrounding a small, solid nucleus.  When, after many trips 
round the sun, all its volatile material has boiled off into 
space, only this core is leftand the comet becomes a normal 
asteroid.

I am proud to say that the International Astronomical Union, which 
is in charge of such matters, recently named an asteroid 
(previously known only by a number, 4923) after me.  It's about 
ten kilometers in diameter, and spends most of its time near the 
orbit of Mars, so I'm afraid its climate is rather chilly.  The 
IAU apologized to me because Number 2001 was no longer available.  
Apparently it had been allocated several years ago, to somebody 
named A. Einstein.

As far as the resulting damage to planet Earth was concerned, it 
would not make the slightest difference whether the impactor was a 
comet or an asteroid.  However, because it is such an impressive 
astronomical object, we could see a comet months before it hit.  
But an asteroid might give only two minute's warning, when the sky 
suddenly exploded...

This happened over a remote part of Siberia in 1908.  Luckily, 
though a huge area of forest was devastated, there was no loss of 
human life.

There have been several other major events since then, again in 
uninhabited areas, and in 1972 there was a hair-raising near-miss.  
On 10 August, a large meteorite streaked half way across the 
United States and was seen not only by thousands of people, but 
recorded by many amateur photographers.  It came within a mere 58 
kilometers of ground level; had its trajectory been slightly 
different, some American city might have emulated Hiroshima.

I'm not sure if this provided any inspiration for my novel 
Rendezvous with Rama, which opened with the destruction of 
Northern Italy by asteroid impact in the year 2077.  This disaster 
resulted in the establishment of a warning system, to which I gave 
the nameSPACEGUARD.  Well, fact has followed fiction.  When the 
U.S.  House of Representatives asked NASA to study the problem, I 
was delighted when the resulting 1992 report was entitled THE 
SPACEGUARD SURVEY, with due acknowledgement.

That same year, a senior editor of TIME wrote to me saying that 
though the magazine had never deliberately published fiction, 
they'd like me to write a short story for a special issue.  The 
result was The Hammer of God, in which I attempted to answer the 
question:  what could we do to save ourselves if we see a killer 
rock headed this way?

The novel-length version of The Hammer of God appeared in 1993and 
just one year later, the whole world had a grandstand view of the 
most spectacular collision ever observed in our Solar System.  The 
impact of Comet Shoemaker-Levy 9 on Jupiter in July 1994 made 
holes in the giant planet's atmosphere larger than the Earth; they 
could be seen even in the smallest telescope, and the after-
effects lingered for months.

Only a few weeks ago, there was a great deal of alarm when the 
initial orbit calculated for the newly-discovered asteroid 1997 
XF11 suggested that it might collide with Earth in the year 2028.  
Luckily, after a hunt through the thousands of photographic plates 
collected by astronomers over many decades, an earlier image of 
XF11 was discovered.  This made it possible to compute a much more 
accurate orbit, and we now know that there is no danger from this 
particular asteroidat least for millions of years!

This rather embarrassing affairthe correction came only a day 
after the initial reporthas triggered a major debate in the 
astronomical community.  A protocol is now being drawn up to 
reduce the chance of any premature and perhaps inacurate 
announcement.  And I am happy to say that NASA is now in the 
process of establishing a new office to deal with the problem, 
with an initial annual budget of $3,000,000.

Among the members of NASA's SPACEGUARD Committee is my old friend 
the Dutch-American astronomer Tom Gehrels, one of the world's 
leading experts on asteroids.  He has visited Sri Lanka on several 
occasions, hoping to establish an observatory hereso far without 
success, because of a deplorable lack of interest in astronomy (as 
opposed to astrology!)

This situation, I hope, may be rectified now that the Japanese 
Government has made an extraordinarily generous gift of a half-
million dollar observatory-class telescope, currently located at 
the Arthur Clarke Centre.  Although this is far from being an 
ideal location, the best observing sites are currently 
inaccessible and good work can still be done at Moratuwaif we can 
find experienced and enthusiastic staff.  I might add that most 
comets and many asteroids are discovered by amateurs working with 
telescopes considerably smaller than the one we now possess.

Some might argue that, in a world already nervous about global 
warming, poisoned oceans, DIY nuclear bombs, etc.  etc., any 
discussion of protection from asteroids and comets is a massive 
exercise in irrelevancy.  Yet there is much that canand shouldbe 
done, as is proved by the current intense debate among 
astronomers, space scientists, and under-employed Star Warriors 
looking for new targets.

It is an old ideagoing back at least to Andre Maurois' "The War 
Against The Moon" (1927)that only a threat from beyond the Earth 
could unify the quarrelsome human species.  So it may indeed be a 
stroke of luck that such a threat has been discovered, at just the 
period in history when we can devise technologies to deal with it.

Although some suggested cures may sound worse than the disease (Dr 
Edward Teller has proposed a bodyguard of orbiting H-bombs) there 
are several plausible alternatives.  They all depend on the length 
of the warning time available.

Of the many defenses proposed, the most elegant (and 
environmentally friendly!) one is to rendezvous with any asteroid 
on an orbit liable to impact Earth, and to persuade it to make a 
slight change of course.  If there was sufficient warning time, 
only a modest amount of rocket propulsion would be necessary.  
This was the scenario I developed in The Hammer of God, which was 
later optioned by a promising young movie-maker named Steven 
Spielberg.  I don't know how much of my story he has used, but I 
have a double interest in Deep Impact, as he is calling the film.  
The role of the first black President of the United States is 
played by Morgan Freeman, now considered by many to be the finest 
actor in America.  Well, Morgan has just optioned my own 
Rendezvous with Rama, which started the whole SPACEGUARD business.  
I can't wait...

Meanwhile SPACEGUARD Foundations have been set up in the UK, the 
US and Australia, to persuade governments to fund a survey which 
would, for the first time, give us some idea of the real extent of 
the danger.  At the moment, we probably do not know even one tenth 
of the NEO'sNear Earth Objectswhich must exist.

In one of his last books, Carl Sagan pointed out that no really 
long-lived civilization could survive unless it develops space 
travel, because major asteroid impacts will be inevitable in any 
solar system over the course of millennia.  Larry Niven summed up 
the situation with the memorable phrase:  "The dinosaurs became 
extinct because they didn't have a space program."  And we will 
deserve to become extinct, if we don't have one.

* Luis was a good friend of mine, and I dedicated my 1963 novel 
Glide Path to him.  This work of barely disguised fiction was 
based on my experiences as an RAF officer when I took over the GCA 
(Ground Control Approach) radar blind-landing system which "Luie" 
had invented at the Massachusetts Institute of Technology.  The 
main protagonist was modeled on him, and I am very happy that my 
prediction of his Nobel Prize came true a few years later.


BIOSPHERE LESSONS CAN BE APPLIED TO SPACE, FORMER CREW CO-CAPTAIN 
SAYS
Wake Forest University School of Medicine release

12 May 1998

The experiences of the team of scientists who lived in the 
Biosphere 2 closed system from 1991 to 1993 can be applied to 
space travel, according to Sally Silverstone, co-captain of the 
crew.  Long-term space missions will require life support systems 
similar to the steel and glass structure north of Tucson, Ariz., 
where eight scientists lived for two years, Silverstone said.

Silverstone spoke at symposium on future directions in space life 
science research at a meeting of the Space and Underwater Research 
Group of the World Federation of Neurology here today.  The 
meeting is being coordinated by the Stroke Research Center of the 
Wake Forest University Baptist Medical Center.

Biosphere 2 was sealed and open only to sunlight.  The structure 
had systems that provided water, food, air regeneration, and 
wastewater recycling.  Inside Biosphere 2, a half-acre cropping 
area produced enough food to meet about 80 percent of the crew's 
nutritional needs, she said.  Biosphere 2 also contained a rain 
forest, a million-gallon ocean with a coral reef, a desert, a 
savanna, a marsh, 3,800 species of plants and animals, as well as 
living quarters for the crew of four men and four women.

In future space travel such as a base on another planet, similar 
"biospheres" may be used that would have a closed environment open 
to energy from the sun.  As with Biosphere 2, nothing but ambient 
light could pass through the barrier, requiring the base to 
provide the atmosphere, water and nutrients to keep the operators 
of the base going.  About one fourth of the crew's time was spent 
on managing the agricultural fields.  Food preparation took 12 
percent of the crew's time and animal care took 9 percent of their 
time.

Silverstone spoke about the future research specifications for 
long-term missions, as well.  The whole basic concept has been 
pretty well proved, she said.  But there are many areas that need 
to be studied, she said.  Among the research needs are:

* How to increase crop production in smaller spaces.

* Comparing use of artificial lighting to ambient lighting to see 
what is missing.

* Understanding atmospheric recycling because certain nutrients 
can get tied up more than others.

* Determining recreational needs of the crew in space.

Silverstone, who is the vice president of Agricultural and 
Forestry for Ecofrontieers Inc.  and shareholder of Biospheres 
LLC, a private research and development firm, was the co-captain 
of the Biosphere 2 crew and manager of agriculture and food 
systems.  She has worked on food and agricultural projects in East 
Africa, India and Puerto Rico.  A native of England, she managed 
and coordinated the architectural division operations, financial 
administration and cost control from 1987 to 1991 for Space 
Biospheres Ventures, the company that built and operated Biosphere 
2.  In addition to publishing papers on the agricultural systems 
of Biosphere 2, she has published a cookbook, Eating In:  From the 
Field to the Kitchen in Biosphere 2.


YALE RESEARCHERS SYNTHESIZE ENZYME THAT MAY HAVE PLAYED KEY ROLE 
IN FORMATION OF LIFE
By Vincent Kiernan
Copyright  1998 by The Chronicle of Higher Education 

26 May 1998

Researchers at Yale University announced today that they had 
synthesized a molecule similar to substances that they believe 
played a key role in the formation of primordial life forms on the 
earth four billion years ago.  The moleculea hybrid of 
deoxyribonucleic acid and the amino acid histidineis an enzyme 
that destroys messenger ribonucleic acid, genetic material that 
cells use to transcribe information contained in DNA.

The substance was synthesized by Ronald R. Breaker, an assistant 
professor of biology, and Adam Roth, a postdoctoral research 
associate.  They reported the development in today's issue of the 
Proceedings of the National Academy of Sciences.

Most organisms store their genetic information in DNA.  But some 
scientists, such as Dr. Breaker, believe that primordial organisms 
used ribonucleic acid, not DNA, as their storehouse for genetic 
information.  In the view of these scientists, double-stranded 
DNAwhich has a more complex structure than ribonucleic acid
developed later.  But organisms based solely on ribonucleic acid 
and lacking DNA would have needed enzymes that could manipulate 
ribonucleic acids.

Dr. Breaker's experiment did not go that far:  It showed only that 
DNAnot ribonucleic acidcould form enzymes.  But DNA and 
ribonucleic acid are made from many of the same chemical building 
blocks, so the experiment lends credence to the notion that 
ribonucleic acid could have formed enzymes on the primordial 
earth, he says.

"Our experiment shows for the first time that that is indeed 
possible," says Dr. Breaker.


MARS SOCIETY FOUNDING CONVENTION
August 13-16, 1998
University of Colorado, Boulder

Dr. Robert Zubrin, author of The Case for Mars, would like to 
invite you to participate in the Founding Convention of the Mars 
Society.

This summer, over 1000 scientists, engineers, visionaries, 
philosophers, explorers, businessmen, journalists, historians, 
politicians, and other citizens will join in a historic gathering 
to found an association committed to the exploration and 
settlement of Mars by both public and private means.
Be there.

Sessions Announced!
Thirty Six sessions are now planned for the conference.  These 
sessions include:
1.	Concepts for Privately Funded Mars Missions
2.	Current Plans for Robotic Mars Exploration
3.	Mars Meteorite AH84001:  Evidence for Life?
4.	Latest Findings of the Pathfinder and Mars Global Surveyor 
Missions
5.	The Search for Life on Mars
6.	The Contamination Hazard:  Fact or Fiction
7.	Concepts for Future Robotic Mars Exploration Missions
8.	Piloted Mars Exploration Missions
9.	Use of Local Resources
10.	Methods of Construction on Mars
11.	Advanced Propulsion
12.	Options for Producing Power On Mars
13.	Gaining Access to the Martian Hydrosphere
14.	Biomedical Issues in Mars Exploration
15.	Space Launch Options for Mars Exploration and Settlement
16.	Life Support Technology
17.	Human Factors
18.	Technologies for Achieving Long Range Mobility on Mars
19.	Concepts and Technologies for a Permanent Mars Base
20.	The Economics of Mars Colonization
21.	Social Aspects of Mars Colonization
22.	Timekeeping and Calendar Systems for Mars
23.	Mars as a Way Station to Worlds Beyond
24.	Terraforming Mars
25.	Mars Exploration and American Public Policy
26.	International Collaboration as a Path to Mars
27.	The Need for Law on Mars
28.	Risk and Exploration:  How Much is Acceptable?
29.	Methods of Public Outreach
30.	Mars and Education
31.	Mars and the Arts
32.	The Role of Women in Exploration and Settlement
33.	Potential Philosophical Impacts of Mars Exploration
34.	The Human Need to Explore
35.	The Significance of the Martian Frontier for Future Human 
History
36.	The Founding Declaration of the Mars Society

Conference Registration Fee:  $140 before June 30, 1998, $180 
afterwards.

Call for Papers
Papers for presentations at the convention are requested dealing 
with all matters (science, engineering, economics, and public 
policy) associated with the exploration and settlement of Mars.  
Abstracts of no more than 300 words should be sent by 5/31/98 to:  
Mars Society, Box 273, Indian Hills, CO 80454 USA

Written papers are not required for presentation at the 
conference.  However papers submitted in writing will be published 
in a series of special issues in the Journal of the British 
Interplanetary Society and compiled for publication in book form 
to be published by Univelt Inc.

Co-sponsors Boost Effort
The following organizations have stepped forward to co-sponsor the
Founding Convention of the Mars Society:
The National Space Society
The British Interplanetary Society
The World Space Bar
United Societies in Space
Pioneer Astronautics
The Boulder Center for Science and Policy
Fisher Space Pen

Journal Founded!
The Mars Society has initiated an electronic magazine entitled, 
New Mars:  The Journal of the Martian Frontier.  New Mars will 
feature news of technical advances, scientific findings, political 
developments, as well as feature articles discussing scientific, 
engineering, social, historic, and public policy issues relating 
to the exploration and settlement of Mars.  The editor of New Mars 
will be Richard Wagner, the former editor of the National Space 
Society's Ad Astra Magazine.  Contributions are solicited.

Further information on both the Founding Convention and the New 
Mars journal can be found at:  http://www.nw.net/mars


THE MARS MICROPHONE:  READY TO GO
By Greg Delory

Ever wonder what it sounds like on Mars? When the next lander in 
NASA's program to explore the Red Planet touches down in 1999, we 
will all have the chance to find out.  Onboard the Mars Polar 
Lander will be a small recording device, the Mars Microphone, 
whose job is to sample sound while the rest of the probe studies 
the soil, weather, and atmospheric dust.

The idea for the Mars Microphone started with Janet Luhmann of the 
University of California, Berkeley and David Juergens of the Jet 
Propulsion Laboratory, who proposed to the Planetary Society that 
a sound-recording device would be easy to include on a Mars 
mission.  Society Executive Director Louis Friedman investigated 
the possibility of incorporating a microphone in the Mars Polar 
Lander mission.

At that time, mission planners had just selected a Russian 
instrument to be put aboard the spacecraft (the first Russian 
instrument included on a US planetary mission).  Under the 
direction of Viacheslav Linkin of the Space Research Institute in 
Moscow, the lidar will use a laser to study the distribution of 
dust in the Martian atmosphere.  Linkin offered a place on the 
lidar for the microphone, which could operate without requiring 
any mass, power, volume, or data-rate adjustments on the lander.

Friedman and Society President Carl Sagan then requested NASA 
approval to include the microphone in the Mars Polar Lander 
payload, stipulating that there would be no cost to NASA.  NASA 
Associate Administrator for Space Science Wes Huntress agreed.

The Planetary Society formed a team with the Space Sciences 
Laboratory at Berkeley, and together we developed a low-cost 
implementation plan that enabled us to build the instrument with 
funding solely by the Planetary Society.

The Mars Microphone will be the first instrument funded by a 
membership organization to fly to another world.  It was designed, 
constructed, and tested under Luhmann's direction at the Space 
Sciences Laboratory.

Are There Sounds on Mars?

Given that sound waves need an atmospheric medium through which to 
travel, many people are surprised to learn that any sounds at all 
can be heard on Mars.  The atmospheric pressure on the surface of 
the Red Planet is small, amounting to around 0.1 percent of the 
Earth's sea level pressure.  But even at Mars' low pressure, 
acoustic signals within the frequency range of the human ear can 
be detected.  And while the atmosphere of Mars is very different 
from Earth's, consisting mostly of carbon dioxide, there are 
similarities between these environments that should make the sound 
data worthwhile.

For example, there is weather on Mars, including winds, 
sandstorms, and dust devils, which are little tornadoes caused by 
local weather patterns.  The Mars Microphone may be able to hear 
these winds and perhaps even a type of lightning within 
sandstorms.  The microphone will also record noises made by the 
lander, such as the sound of the robotic arm digging for soil 
samples.

However, the most exciting sounds are likely to be ones that we 
don't even know about yet.  Experience has demonstrated that 
whenever a new instrument is developed and flown in space, we 
learn something new about extraterrestrial environments, and 
therein lies the true spirit of the Mars Microphone concept.

The instrument will bring the public closer to Mars exploration.  
The sounds picked up by the Mars Microphone will be available on a 
World Wide Web page during the mission so that anyone will be able 
to hear for themselves what it sounds like on Mars.

Building and Testing on a Shoestring

The Mars Microphone is a small device, roughly 5 centimeters on a 
side and one centimeter thick (2 x 2 x 0.5 inches), weighing less 
than 50 grams (1.8 ounces) and using a small amount of power, less 
than 0.1 watt during its most active times.  In addition to the 
microphone, the instrument contains digital electronics to acquire 
and store sound samples.  Because the rate at which we can acquire 
data will be limited, it will take several days, maybe even a 
week, to retrieve one 10-second sound clip.  The device has 
internal memory, similar to the RAM in your home computer, which 
will store sounds for transmission to Earth along with other 
lander data.

In the construction of the Mars Microphone, we relied on 
commercial, off-the-shelf technology, meaning that very few of the 
components were developed specifically for this mission.  Most are 
readily available commercially.  Our sound processor chip, for 
example, is also used in talking toys and educational computers 
that listen and respond to spoken words.  The microphone itself is 
typically used in hearing aids.  The entire program, including 
design, construction, and testing, cost roughly $50,000, a bargain 
for an instrument on a planetary probe.

The Mars Microphone has since passed several tests to show it can 
withstand the rigors of a planetary mission.  Radiation levels in 
space and on Mars are higher than what we are used to on Earth, 
and, like humans, the electronic components in the microphone are 
sensitive to radiation damage.  We exposed the microphone and the 
sound processor chip to levels of radiation that they would 
receive during the mission, and there were no failures or 
degradation of performance.  We also conducted thermal tests with 
temperature ranges of -100 to +20 degrees Celsius (about -150 to 
+70 degrees Fahrenheit), and detected no malfunctions.

Finally, we performed pressure tests to ensure that the microphone 
could actually hear noises at the low pressures of the Martian 
atmosphere.  Although sound level diminishes substantially with 
decreased pressures, we were still able to hear sounds by 
increasing the gain of the amplifiers within the microphone.

The microphone was integrated onto the Mars Polar Lander last 
October at Lockheed Martin in Denver, Colorado.  We verified that 
the microphone worked properly on the lander and even listened to 
the technicians conversing as they tended to the craft.

The next phase of testing will occur this summer, when the entire 
lander plus microphone will undergo thermal and vacuum tests to 
simulate the journey through space and operations on the Martian 
surface.  During this time the microphone will practice listening 
to the movements of the lander's robotic arm.

For the latest on the Mars Microphone project and more details 
about the experiment, visit the Mars Microphone home page at
http://sprg.ssl.berkeley.edu/marsmic.

Greg Delory is a postdoctoral physicist at the Space Sciences 
Laboratory of the University of California, Berkeley.


1998 MARS SURVEYOR PROJECT STATUS REPORTS
By John McNamee, Mars Surveyor 98 project manager

15 May 1998

Orbiter integration and test activities are proceeding on 
schedule.  Mission system testing of the mapping phase is in 
progress.  The Mars Color Imager (MARCI) flight instrument has 
been removed from the orbiter to allow upgrading of the color 
filter array.  Troubleshooting of the various Pressure Modulator 
InfraRed Radiometer (PMIRR) anomalies continues.  The PMIRR 
chopper motor is scheduled for removal from the instrument on May 
19 for troubleshooting at the vendor (Honeywell).

Lander integration and test activities are proceeding on schedule.  
The lander was moved into the thermal vacuum chamber on May 11 and 
chamber pump down for cruise configuration thermal vacuum testing 
will begin on May 16.

22 May 1998

Orbiter integration and test activities are proceeding on 
schedule.  Mission system testing of the mapping phase which 
involved the execution of the flight mapping sequences was 
completed successfully.  Troubleshooting of the various Pressure 
Modulator InfraRed Radiometer (PMIRR) anomalies continues and much 
progress has been made in resolving these problems.  None of the 
PMIRR problems appear to be major obstacles to the launch of the 
orbiter.

Lander integration and test activities have been disrupted due to 
an anomaly involving the capillary pump loop (CPL) thermal control 
hardware.  The cruise thermal vacuum test was interrupted on May 
19 after the test team was unable to keep the CPL's primed and 
running during the test due to known design deficiencies and 
artifacts of the test set up.  After a thorough review by Lockheed 
Martin and JPL Project and Off-Project engineers the decision was 
made to resolve all CPL design issues before proceeding with any 
further cruise thermal vacuum testing or landed thermal balance 
testing at Mars ambient.  This approach allows the thermal 
subsystem engineers to focus on solving the core design problem 
with CPL operation on the pad, during ascent, and in early cruise 
without the diversion of designing an alternative test set up that 
could allow completion of the cruise thermal vacuum test 
objectives in a non-flight configuration.  The alternative test 
set up approach was viewed as too high risk in terms of schedule 
and potential hardware damage.

For more information on the Mars Surveyor 98 mission, please visit 
this website:
http://mars.jpl.nasa.gov/msp98/


STARDUST STATUS REPORTS
By Ken Atkins, STARDUST project manager

15 May 1998

Assembly, Test, and Launch Operations (ATLO) activities:  ATLO 
this past week involved harness modifications to achieve a 
compatible timing interface and grounding for the Navigation 
Camera scan-mirror motor, Inertial Measurement Unit (IMU #2) 
installation, Attitude Control System interface testing and 
spacecraft functional testing.  The formal ATLO Pre-Environmental 
Test Review was conducted.  The Board concluded that STARDUST is 
ready to proceed to its environmental test.

Aerogel:  The ATLO Test Unit (ATU) aerogel trays were installed in 
the Sample Return Capsule (SRC).  The installation procedure was 
practiced in the SRC Structural/Thermal Model.  JPL aerogel team 
members participated in the aerogel collector inspection and 
installation.

Outreach:  After the film "Deep Impact" opening and the 
announcement of the new round of name collections, the STARDUST 
home page jumped to a peak of 64,239 hits on May 11, and has been 
averaging 51,600 hits per day for the week.  About 86,000 names 
have already been collected.  There is a link to the Stardust name 
collection form from the Deep Impact homepage at:
http://www.deepimpactmovie.com

STARDUST was also the highlighted feature on the Space Day home 
page at:
http://www.spaceday.com/thisweek/index.htm

22 May 1998

Assembly, Test, and Launch Operations (ATLO) activities:  
Activities this past week included the successful first run of the 
"Aliveness Test."  This test confirms all subsystem interfaces are 
operational and "healthy."  Also, one spacecraft side panel (+Y) 
was folded up to allow installation of the Cometary & Interstellar 
Dust Analyzer (CIDA) sensor.  The gold "saxaphone-like" sensor, 
delivered this week by the German CIDA team, is clearly visible in 
the video picture from Lockheed Martin.  Installation and initial 
testing went very well.  Congratulations to the CIDA team!  The 
silver horn in the picture is the medium gain antenna...a key 
element of the telecommunications subsystem.

Outreach:  Public interest in the film "Deep Impact" has continued 
to improve public awareness of STARDUST by the film-folk's help in 
facilitating the new round of name collections for the second 
microchip to be flown in the Sample Return Capsule (SRC).  As of 
May 20, 146,274 names had been collected.  This exceeds the total 
number of names collected for the first microchip.  As many, many 
more interested fans join us...  a hearty, "Welcome Aboard."

In another familiar setting, the STARDUST Project provided Aerogel 
for an interesting exhibit in Disneyland's premier of the New 
Tomorrowland.  The Official Grand Opening is this Memorial 
weekend.

On Thursday, there were 109,228 hits to the home page, a new 
record for STARDUST!

Thanks for looking in!  We encourage you to browse through the 
site.  You can listen to STARDUST-related music by hitting the 
jukebox in the STARDUST Cafe 
(http://stardust.jpl.nasa.gov/info/sd-cafe.html), or you can check 
out some great coloring work by kids if you click the words "Color 
me STARDUST" on the "What's New?" page.  You can also find out 
where comet Wild-2 is right now 
(http://stardust.jpl.nasa/gov/comets/wildnow.html).  And for 
newcomers, certainly don't forget the STARDUST name collection 
form (http://stardust.jpl.nasa.gov/microchip/signup.html).  And, 
as you browse, look for the great links to our partner's sites 
such as Jason, Challenger Centers, and OmniPlex.

For more information on the STARDUST missionthe first ever comet 
sample return mission, please visit the STARDUST home page:
http://stardust.jpl.nasa.gov


GALILEO EUROPA MISSION STATUS
JPL release

14 May 1998

The Galileo spacecraft has spent the week processing and 
transmitting to Earth pictures and science information gathered 
during its March 29 flyby of Jupiter's moon Europa.  The material 
had been stored on the spacecraft's onboard tape recorder.

Some of the information would have been transmitted last week, but 
it was delayed in the name of science when the Galileo team gave 
up some antenna time at the Deep Space Network's 70- meter (230-
foot) antenna in Canberra, Australia.  The antenna was needed to 
support radio frequency observations of a newly identified gamma 
ray burst.

Included in this week's batch of information transmitted to Earth 
by Galileo are two images of a region of Europa notable for its 
dark spots.  Together, these images provide a stereo topographic 
view of the area.  Another observation measures the varying light 
intensities on Europa, information that helps scientists identify 
different surface materials.  An observation from Galileo's near-
infrared spectrometer should provide more information on the 
materials that make up the region of Europa, which has dark spots 
and pull-apart wedge sections.

The spacecraft is sending back previously recorded information 
that will beef up knowledge of the interaction between Jupiter's 
magnetic and electric fields and Europa.  Last week, the Galileo 
team modified the spacecraft's onboard attitude control software.  
However, the adjustment did not change the gyroscope's behavior as 
the team had hoped.  A second modification was made Wednesday, May 
13, and early tests indicate that the procedure was a success.  
Another gyro performance test is scheduled this Friday, May 15, 
and the Galileo team expects it will confirm that the attitude 
control system is now performing as planned.  The attitude control 
system has been behaving anomalously since the spacecraft's 
closest flyby to Europa last December 16.  The Galileo team has 
been able to operate the spacecraft in such a way that the anomaly 
has had very little effect on the spacecraft's performance.  
Nonetheless, engineers continue to analyze the situation, which 
they believe is related to the spacecraft's repeated exposure to 
Jupiter's strong radiation.

Galileo's next Europa flyby will take place on May 31, 1998, at an 
altitude of 2,521 kilometers (1,566 miles).  The spacecraft 
successfully completed its primary mission in December 1997 and is 
now in its two-year extension, the Galileo Europa Mission.  
Current plans include four more Europa flybys after the May 
encounter, four Callisto flybys, and one or two of Io, depending 
on spacecraft health.


THIS WEEK ON GALILEO
JPL releases

18-24 May 1998

With just about two weeks remaining before its next close 
encounter with Jupiter's moon Europa, Galileo spends this week 
continuing to process and transmit to Earth science data gathered 
during its previous encounter in late March.  Data processing is 
interrupted once this week, on Wednesday, to turn the spacecraft 
to keep the radio antenna pointed toward Earth, and to perform 
regular maintenance on the spacecraft's propulsion system.

Only two observations are on the processing and transmission 
schedule this week.  Both were performed by the spacecraft's 
camera, or solid state imaging subsystem, and contain science 
information describing Europa.  The first is a high-resolution 
picture of the Tyre Macula crater region.  This region contains a 
circular feature about 140 kilometers (87 miles) in diameter 
(about the size of the island of Hawaii) and is thought to be the 
site where an asteriod or comet hit Europa's ice crust.  The 
second observation contains a region that shows a transition from 
bright plains to pull-apart wedges.  These features suggest that 
the surface crust has been separated and filled with material from 
below the surface.

Last week, flight team engineers sucessfully identified and 
corrected a minor error in an update to the attitude control 
computer's onboard software that had been performed on Sunday, May 
3.  The original software update had not been performing as 
expected.  Testing performed after this latest update has shown 
that the software is now performing as designed and the attitude 
control computer should be able to correct and use the output from 
the gyroscope that has been behaving anomalously since December 
1997.

25-29 May 1998

Galileo spends this week preparing for its next passage through 
the heart of the Jupiter system.  The encounter is scheduled to 
start this Saturday, May 30, and features a flyby of Jupiter's 
moon Europa at an altitude of 2516 kilometers (1564 miles).

Preparation for the encounter includes completion of processing 
and transmission to Earth of science information still stored on 
the spacecraft's onboard tape recorder.  The data was acquired 
during Galileo's previous flyby of Europa in late March.

Data processing and transmission is interrupted once this week, on 
Thursday, when the spacecraft executes the final flight path 
correction prior to the close flyby of Europa.

Five observations remain on the data processing schedule.  The 
first is a global color observation of Europa, performed by the 
spacecraft's camera.  The image will provide information 
describing the global geology of Europa, specifically the origin, 
composition, and distribution of materials on the surface.  The 
camera team also returns a global color observation of Ganymede.  
Similar to the Europa observation, the information returned will 
describe the radius, shape, color, and composition of Ganymede's 
surface.  The camera team also returns an observation of Io.  
Acquired while Jupiter eclipsed Io from the sun, this type of data 
has proved to be the best way to discover and monitor lava 
temperatures and barely visible interactions between volcanic 
plumes, Io's atmosphere and Jupiter's magnetosphere.

The remaining two observations are returned by the near infrared 
mapping spectrometer team.  One is the second of a set of three 
distant observations of Europa.  The other is a global map of 
Callisto designed to provide more data describing the materials 
found on the surface.

Don't forget!  Galileo's next encounter starts this Saturday, May 
30, and with it comes the return of Today on Galileo.  

For more information on the Galileo spacecraft and its mission to 
Jupiter, please visit the Galileo home page:

http://www.jpl.nasa.gov/galileo


NEW GALILEO IMAGES OF EUROPA
JPL release

21 May 1998

The following images of Europa taken by the Galileo spacecraft are 
now available on the Galileo home page:  
http://www.jpl.nasa.gov/galileo

Europa's Scrambled Ice
Inside Europa's Mannann'an Crater
A Closer Look At Chaos On Europa
Small Craters on Europa
A Dark Spot on Europa
Topography Within Europa's Mannann'an Crater
Europa Imaging Highlights During GEM


End Marsbugs Vol. 5, No. 14

