MARSBUGS:  

The Electronic Exobiology Newsletter

Volume 5, Number 10, 15 April 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)	IS THERE LIFE ON MARS:  A HISTORY OF DIFFICULTIES IN 

INTERPRETING THE OBSERVATIONAL AND EXPERIMENTAL EVIDENCE.

by Richard Taylor



2)	SITE SELECTION FOR MARS EXOPALEONTOLOGY

by Jack Farmer and Dave Des Marais



3)	MARS EXPLORATION STUDIES OF JBIS--BOOK REVIEW

by Julian Hiscox



4)	NEW MITIGATION STRATEGY MINIMIZES RISK OF ASTEROID COLLISIONS

University of Illinois release



5)	INCREASING GREENHOUSE GASES MAY BE WORSENING ARCTIC OZONE 

DEPLETION AND MAY DELAY OZONE RECOVERY

NASA release 98-58



6)	GLOBAL SURVEYOR SCHEDULES IMAGING OPPORTUNITIES FOR VIKING, 

PATHFINDER, CYDONIA REGIONS OF MARS

JPL release



7)	PROCESSED MARS GLOBAL SURVEYOR IMAGES OF THE CYDONIA REGION 

RELEASED

by Ron Baalke



8)	MARS ORBITER CAMERA VIEWS THE "FACE ON MARS"

From the Mars Global Surveyor home page



9)	EDINBURGH SCIENTISTS BID TO JOIN NASA "LIFE IN THE UNIVERSE" 

STUDY

by Jacqueline Mitton



10)	SHUTTLE MISSION'S "NEUROLAB" TO STUDY NERVOUS SYSTEM

NSF release



11)	JPL EVENING LECTURES HIGHLIGHT EARTH EXPLORATION MISSIONS

JPL release



12)	SCIENCE TEAM CHOSEN FOR TECHNOLOGY VALIDATION MISSION TO 

EXPLORE THE SUBSURFACE OF MARS

NASA release 98-59



13)	MARS GLOBAL SURVEYOR FLIGHT STATUS REPORTS

JPL releases



14)	MARS SURVEYOR '98 PROJECT STATUS REPORT

by John McNamee



15)	MARS POLAR LANDER PHOTOS

JPL release



16)	STARDUST STATUS REPORT

by Ken Atkins



17)	GALILEO EUROPA MISSION STATUS 

JPL release





IS THERE LIFE ON MARS:  A HISTORY OF DIFFICULTIES IN INTERPRETING 

THE OBSERVATIONAL AND EXPERIMENTAL EVIDENCE.

by Richard Taylor, Probability Research Group.



Mars has been observed and studied throughout recorded history but 

scientifically speaking it was only in the late 19th Century that 

astronomers began to build observatories with telescopes large 

enough and of high enough quality to reveal detail on the surface 

of the planet.  Up to the 1950's our knowledge of Mars was gained 

entirely by observing the planet for relatively short periods of 

time at approximately two-year intervals, when the planet was in 

opposition.  Because of the eccentricity of the Martian orbit not 

all oppositions are equally favorable for high quality 

observations.  Astronomers thus had to work visually and use 

photographic techniques or telescope mounted instruments that were 

stretched close to their limits of performance.  For these reasons 

obtaining reliable data in any quantity was a difficult 

undertaking.



Until 14 July 1965, the date of the Mariner 4 flyby of Mars, the 

scientific study of the planet had been largely descriptive, and 

it must be said to an undefinable degree, subjective.  Ever since 

the first successful Martian space probe the basis of the study of 

Mars has moved from being largely descriptive, to being based upon 

the acquisition of accurate measurements and hence truly objective 

data, and has even included conducting experiments upon the 

surface of the planet itself.  To put it simply to begin to really 

understand the planet we needed to see Mars from close-up.  Once 

we had gained this ability scientists, chiefly planetary 

astronomers and biologists, hoped that one of the most fascinating 

questions that has long held the attention of all of us--is there 

life elsewhere in the universe, and especially on Mars--might soon 

be answered for certain with a clear yes or no.



There was no real possibility of doing this until we were able to 

undertake space research missions, but after 34 years of probing 

Mars and collecting a truly immense amount of data just how close 

have we come to answering just the question, "Is there life on 

Mars?"  The answer seems to be that today although we know more 

about Mars and the possibilities for life beyond Earth than ever 

before, we are no closer to giving an assured yes or no to the 

question.



Even in the case where it is possible to examine actual samples of 

Martian rocks, in the form of SNC meteorites, we are unable to 

overcome ambiguities and uncertainties in the analysis and 

interpretation of the data.  And these rocks, delivered by chance 

to the Earth, can be examined in terrestrial laboratories using 

some of the most sophisticated techniques available.  The original 

paper by McKay, Gibson, et al., describes work that provides 

several types of evidence the complete assemblage of which is open 

to a number of possible interpretations.  The controversial nature 

of differing interpretations has sprung to attention many new 

publications either supporting or refuting the conclusions of 

David McKay’s group.  The controversial interpretations arising 

from this "Earth-based" study of Martian meteorites is set to run 

for some considerable time, but it is instructive to compare what 

is happening in the course of these current investigations with 

the outcome of the experiments conducted by the Viking Landers 

which touched down on Mars 22 years ago in 1976.



A number of experiments placed on the Viking Landers were designed 

specifically to search for biological and/or chemical activity 

consistent with the presence of life.  The different experiments 

were conceived to search for life similar to that found on Earth 

as well as for a form of life more specifically adapted to the 

prevailing conditions on Mars.  This approach automatically 

carried with it the possibility that the overall assessment and 

integration of the individual experimental results could not be 

guaranteed to be free of ambiguity in interpretation.



There were three key Viking "life" experiments.  Gilbert Levin was 

responsible for the "labelled release" experiment.  This assumed 

that any Martian microorganisms, like those on Earth, would 

assimilate simple organic compounds and decompose them into end 

products such as CO2, CH4, or H2 as end products.  For this reason, 

a dilute aqueous solution of seven such organic compounds, 

radioactively labeled for detection purposes, was added to the 

incubation chamber containing the Mars soil sample.  The 

experiment tested for the expected labeled release of the gas 

produced as any organisms ate the organics and breathed out the 

decomposition products in the form of radioactive disintegrations 

in counts per minute measured by a carbon-14 detector.



The "gas exchange" experiment developed by Vance Oyama of NASA 

Ames Laboratories tested for life under two different conditions.  

In the first it was assumed that the addition of a small amount of 

water to the dry Martian environment would stimulated any 

organisms present to more rapid metabolic activity and that any 

gas released immediately above the sample would be detectable by 

chromatography.  The second approach involved the addition of a 

rich "wet" nutrient containing 19 organic compounds to the Martian 

environment.  Again the presence of life would be indicated by the 

release of gas by the increased metabolic activity and would also 

be detected by chromatography.  In neither case did the added 

liquid come into direct contact with the Martian soil sample but 

was placed underneath the porous bottom of the incubation cell 

containing the soil.  This allowed water vapor to seep gradually 

into the incubation chamber creating gradations of moisture 

throughout the soil.  Additionally experiments could be performed 

without the addition of water.



The team responsible for the "carbon assimilation" experiment--

which came to be more widely known as the "pyrolytic release" 

experiment--was headed by Norman Horowitz of Caltech.  In the 

early 1960s Horowitz had co-operated with Levin "labeled release" 

approach for the detection of biological activity on Mars.  

However, after Mariner 4 revealed that the atmosphere of Mars was 

too tenuous to allow liquid water to exist anywhere on the surface 

of the planet he concluded that a different approach to the 

problem was required and that an experiment should be designed to 

test for Martian organisms under conditions then known to exist on 

Mars, which he concluded amounted to an environment "hostile to 

life to a degree unknown anywhere on Earth."  Given this extreme 

hostility, Horowitz argued that if life existed on Mars it would 

adapted to this harsh environment and maladjusted to significant 

departures from it.  He suggested that experiments that departed 

radically from actual Martian conditions would be unlikely to 

succeed in detecting Martian metabolism, or biological activity of 

any kind.  Thus trying to culture Martian organisms by adding any 

kind of aqueous medium he believed to be a mistaken approach.  To 

meet his requirement of an experiment that conformed with the 

actual post-Mariner 4 conditions Horowitz proposed to add to a 

sample of Martian soil only CO2 and CO, gases known to be present 

in the Martian atmosphere, but with the added gases radioactively 

"tagged" for detection purposes.  It was assumed that any Martian 

life would be carbon based and any such organisms assimilate these 

gases and convert them to organic matter over a suitably long 

period of incubation.  The experiment was incubated for 120 hours 

after which the sample chamber was heated to ~635 degrees 

Centigrade to pyrolyze the organic matter and release the volatile 

organic products the data output was then measured disintegrations 

per minute by a radiation counter.



From the nature of these three experiments we can see from the 

outset that they were molded by preconceptions which were likely 

to make a uniform interpretation of the output data difficult and 

perhaps impossible to make.  In science if we ask the wrong 

question, or at least do not ask the question in exactly the 

correct form, we are likely to get an answer that may not in 

itself be wrong but which it is not possible for us to understand 

completely.



Although all three experiments sought to detect various kinds of 

metabolic activity their approaches and methods of detecting 

output data were different.  The first two, (Levin and Oyama's 

experiments) sought to detect life by the decomposition of organic 

nutrients into gas during metabolism.  Levin's experiment using 

standard radioactive carbon-14 "tracer" techniques as a means of 

detection.  This has the advantage that the method that does not 

effect the chemistry in any way but does allow atmospheric carbon 

to be distinguished from carbon metabolized from the supplied 

nutrients.  Oyama's used gas chromatography for detection.  The 

third experiment (Horwitz) was based on an initial synthesis of 

organic matter, which would incorporate the labeled atmospheric 

gases supplied.  Subsequent pyrolysis of any synthesized organic 

matter would allow it to be detected by the same radioactive 

technique as used by Levin.



The complexity of the apparatus necessary to perform these three 

active biology experiments was immense and it took some five years 

to complete the design, construction and testing before the 

packages were finally delivered early in 1975 for incorporation 

into the Viking Landers which were launched in the summer of the 

same year.  In terms of the likely outcome of these experiments it 

is interesting to note that prior to the actual landings the 

opinions of the three individuals responsible for each of the 

three experiments ranged from optimism as to the chance of the 

discovery of life on the part of Levin, through the 50-50 chance 

espoused by Oyama, to pessimism on the part of Horowitz.  These 

views were to remain substantially unchanged after all the data 

were in and analyzed right down to the present day.



Both Viking landers arrived on the surface of Mars safely and 

successfully one year later in the summer of 1976.  Viking 1 

landed on the Chryse plain on July 20, and on July 28, the biology 

experiments began to return some surprising data.  The labeled 

release experiment evolved gas soon after the nutrient solution 

was added and then with the passage of time the reaction reduced.  

The gas exchange experiment led not only to the release of CO2 but 

also oxygen, however the rate of reaction was so rapid that seemed 

unlikely that it was a result of biological activity.  The 

pyrolytic release experiment also appeared to indicate a positive 

result favoring biological activity.



Thus the initial experimental results appeared to indicate 

positive results for the presence of metabolic activity of some 

kind in two cases and for the presence of a strongly oxidizing 

material in the Martian soil at the Viking 1 landing site in the 

third experiment.  The element of doubt affecting these results 

came not from any of the life experiments per se but from the 

Martian organics experiment.  This had nothing to do with 

biological metabolic activity but was designed to reveal the 

presence of organic molecules in the Martian environment through 

the use of a combination of gas chromatography and mass 

spectrometry.  The results of this experiment, in complete 

contrast with the life experiments showed that no organic 

molecules were present even to levels as low as a few parts per 

billion.



A further ambiguity soon arose with both the pyrolytic and labeled 

release experiments when it was shown that the pretreatment of 

duplicate Martian soils samples by heating prevented the 

previously observed supposed metabolic activity from taking place.  

However the nature of the results of the gas exchange experiment 

and the Martian organics experiment led to the general conclusion 

that there was clear evidence of chemical reactions, they could 

not be attributed unequivocally to biological activity.



Over the ensuing months many more biological experiments were 

performed and reported in scientific journals and just before the 

termination of the biological experimental program in May 1977 

opinions had firmed up to a considerable extent that the result of 

the pyrolytic release experiment was probably nonbiological in 

origin, while the results of the labeled release experiment 

remained ambiguous.  The result of the gas exchange experiment was 

concluded as being evidence for chemical reactions capable of 

releasing oxygen--possibly involving hydrogen peroxide or 

superoxides and was in no way indicative of biological activity.  

To explain the presence and origin of H2O2 and other superoxides it 

is necessary to suppose that the effect of solar radiation acting 

on the small amount of water vapor in the tenuous Martian 

atmosphere is capable of their production and that under Martian 

conditions they can persist unreacted in the surface soils of 

Mars.  This question still remains unanswered.



What are we to make of the outcome of the assessment of the Viking 

1 Lander results, which were confirmed substantially by those of 

the Viking 2 Lander?  The most interesting fact is that after 

considering all the experimental evidence and even though a 

particular experimenter might acknowledge that he accepted that 

"it was not easy to point to a nonbiological explanation for the 

positive results" (Horowitz on his pyrolytic release experiment) 

he remained holding the view he had held prior to the Viking 

landings on Mars.  In doing so he used the argument that it was 

not advisable to abandon Occam's razor although it can be argued 

that in seeking a more complex explanation of the observed 

activity other than the apparently more simple biological 

explanation he was falsifying his own argument.  He did however 

admit that many would maintain that his chosen interpretation is 

unproven, and that they would be right for it is impossible to 

prove that any of the reactions detected by the Viking instruments 

were not biological in origin.  Levin, did not agree with this 

stance and throughout the 1980s and down to the present day he has 

continued to hold the view that a biological interpretation of the 

Viking data, in particular that of the labeled release experiment 

was not only possible, but better satisfied Occam's razor.  In 

reaching this conclusion he too was holding to the opinions he 

held prior to the Viking missions.



Steven J. Dick has pointed out in a discussion of the history of 

the Viking missions in his recent book, The Biological Universe, 

in which he discusses the history of the human search for life 

beyond Earth, that it is not only the actual experimental results 

that we must consider carefully, but also the context within which 

these data were obtained.  Thus on the basis of the same available 

evidence, as Dick points out, it remains possible for Horowitz to 

conclude that these data not only prove the absence of life on 

Mars but also, as Mars offers the most promising extraterrestrial 

habitat for life by far in the solar system, that it is now 

virtually certain that the Earth is the only life bearing planet 

in our region of the galaxy.  Whereas Levin is able to draw quite 

different and almost diametrically opposed conclusions.  In 1988 

Soffen in considering the options for the future exploration of 

Mars wrote of the results of the Viking experiments, "Most 

biologists feel that the results of this first set of metabolic 

experiments are indecisive.  They believe that no life was 

detected, but that we cannot state for certain that we have 

exhausted the possibility… to dismiss biology once and for all 

with our meager data may be premature."



I contend that the forgoing brief history of observational and 

experimental research on the question of the existence or non-

existence of life on Mars, shows that the difficulty in drawing 

conclusions--of saying yes or no in answer to the question of the 

existence of life on Mars--arises not just from the fact that our 

data must necessarily be incomplete.  It is in large part 

conditioned by scientific preconceptions--by belief--the more data 

we have acquired the more difficult it has become to avoid 

"pendulum dynamics" in assessing the possibilities for life on 

Mars or elsewhere.  Opinion swinging often quite wildly between 

the strongly affirmative and the dismissive.

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



SITE SELECTION FOR MARS EXOPALEONTOLOGY

by Jack Farmer and Dave Des Marais

NASA Ames Research Center, Moffett Field, CA.  94035



[Condensed by the authors from:  Farmer, J.D.  and Des Marais, 

D.J.  1998.  Exploring for a record of ancient martian life.  

Journal of Geophysical Research, in press]



Introduction



The microbial fossil record encompasses a wide range of 

information, including cellular remains, stromatolites, 

biofabrics, trace fossils, biominerals and chemofossils.  The 

preservation of fossils is strongly influenced by the physical, 

chemical and biological factors of the environment which, acting 

together, ultimately determine the types of information that will 

be captured and retained in the rock record.



The critical factor in assessing the suitability of a site for a 

microbial fossil record is the paleoenvironment.  The 

reconstruction of ancient sedimentary environments usually 

requires the integration of a wide variety of geological 

information, including the shape, geometry and internal structure 

of sedimentary deposits, their mineralogy, and geochemistry.  For 

Mars, much of our knowledge about past environments is based on 

orbital imaging of geomorphic features.  This evidence provides an 

important context and starting point for site selection.  However, 

our knowledge of the martian surface is quite limited, and a major 

goal of the upcoming exploration effort is to reconstruct the 

history of Martian volatiles, climate, and hydrology as a context 

for the exploration for past or present life.  Mineralogical 

mapping from orbit will be an important key in this effort.



In exploring for evidence of past life, terrestrial experience 

suggests that the long-term preservation of biological 

information, as fossils, occurs under a fairly narrow range of 

geological conditions that are well known to paleontologists (1).  

In detrital sedimentary systems, microbial fossilization is 

favored by rapid burial in fine-grained, clay-rich sediments.  In 

chemical sedimentary systems, preservation is enhanced by rapid 

entombment in fine-grained chemical precipitates.  For long term 

preservation, host rocks must be composed of stable minerals that 

resist chemical weathering, and which form an impermeable matrix 

and closed chemical system that can protect biosignatures from 

alteration during subsequent diagenetic change or metamorphism.  

In this context, host rocks composed of highly ordered, chemically 

stable mineral phases, like silica (forming cherts) or phosphate 

(forming phosphorites), are especially favored.  Such lithologies 

tend to have very long crustal residence times and (along with 

carbonates and shales), are the most common host rocks for the 

Precambrian microfossil record on Earth.



Subsurface Environments



If we assume that a subsurface hydrosphere has been present 

throughout martian history, then life could have originated there 

at any time, perhaps emerging at the surface periodically when 

climate changes, induced by external forcing or endogenous 

processes (e.g. volcanism), allowed liquid water to exist at the 

surface.  The recent discovery of subsurface chemolithoautotrophic 

organisms, which are capable of synthesizing organic substrates 

from CO2 and H2 liberated from the aqueous weathering of basalt, 

is especially relevant as a model for martian life (2).  While a 

subsurface habitable zone may yet exist on Mars, access to such 

environments will likely require drilling to depths of several 

kilometers (3).  Given the technological challenge of deep 

drilling, this is unlikely to occur prior to human missions.  So, 

even if there is extant life on Mars today in subsurface habitats, 

it may be much easier to find its fossil counterparts in ancient 

deposits exposed at the surface.



In exploring for a fossil record in subsurface environments on 

Mars there are several geological situations that may provide 

access to the appropriate materials.  These include 1) ejecta from 

impact craters, 2) talus slopes, debris flows or alluvial fans 

developed below the walls of deep canyons, and 3) the deposits of 

outflood channels.  Examples of aqueous mineral deposits of formed 

in subsurface environments that could harbor a microbial fossil 

record include such things as cements in detrital sedimentary 

rocks, low temperature diagenetic minerals deposited in veins, or 

filling vesicles in volcanic rocks, and hydrothermal deposits 

formed below the upper temperature limit for life (~160 degrees 

C).  But the practical problem with these kinds of deposits is 

that they tend to be disseminated, making up only a small 

percentage of a host rock.  Even with mineralogical information 

provided by the Thermal Emission Spectrometer (TES) presently in 

orbit around Mars (4), predicting their occurrence ahead of time 

may be quite difficult.



Surface Hydrothermal Deposits



The deposits of surficial aqueous sedimentary systems are likely 

to provide the largest targets for site selection.  Of these, the 

deposits of hydrothermal systems (subaerial and subaqueous thermal 

springs) have been discussed previously (5).  It is likely that 

hydrothermal systems were widespread on Mars early in its history 

and a number of common geo-tectonic settings on Mars are likely to 

have hosted hydrothermal activity (6).  However, the deposits of 

surface spring systems are likely to be difficult to find as well.  

On Earth, exposure areas for hydrothermal spring mounds are 

typically a few square kms, less than a single TES pixel.  But 

such deposits may be quite abundant within some volcanic terrains.  

It is estimated, for example, that between 15-20% of the floor of 

Yellowstone caldera is covered by thermal spring deposits.  In 

such abundances, subaerial sinters could well be detected by TES.  

Where exposed, the shallow subsurface portions of these systems 

may be quite a lot larger (perhaps tens of square kms), although 

(as noted above) mineralization may be finely disseminated in the 

basement rock, making remote detection more difficult.



Paleolake Basins



There are a large number of potential paleolake basins on Mars 

(inclusive of impact craters and volcanic calderas) that have been 

previously identified using Viking images (7).  However, deposits 

of paleolakes may offer the largest and most easily identified 

exopaleontological targets from orbit.  Based on a variety of 

arguments, some workers have suggested that there was once an 

ancient ocean on the northern plains (8), and some sites of 

interest (potential shoreline terraces) fall within the 30degN 

constraint.  From a paleontological standpoint the most 

interesting places of this type are terminal paleolake basins 

which are likely to have been both saline and alkaline.  Models by 

Schaefer (9) suggest such environments could be widespread on 

Mars.  The conditions in terminal lake basin settings favor 

widespread chemical sedimentation, an important condition for 

microbial fossilization.  Important lithological targets for a 

microbial fossil record in terminal lake basins include spring-

deposited carbonates, shoreline cements, a wide variety of 

evaporite minerals and fine-grained detrital sediments including 

shales, marls, and water-lain volcanic ash deposits.



Facies Models as Tools for Exploration



In developing a strategy to explore for ancient hydrothermal 

deposits on Mars, we can learn from the methods that have been 

developed by explorationists to explore for economic mineral 

deposits on Earth (10).  Due to their simple mineralogy, 

hydrothermal deposits can often be detected using remote sensing 

methods (11).  Common thermal spring mineral assemblages include 

silica, carbonate, and various metallic oxides and sulfides.  But 

there are also a number of diagnostic silicate minerals, including 

clays, formed by the hydrothermal alteration of country rocks 

(12).  These hydrothermal minerals have characteristic spectral 

signatures that could be detected from Mars orbit using high 

resolution infrared remote sensing methods (13).  In playa lake 

settings, evaporite deposits often form a predictable "bull’s eye" 

pattern with carbonates being deposited in marginal basin areas, 

and sulfates and halides occurring progressively more basinward 

(14).  The floors of some impact craters on Mars, such as "White 

Rock" (16) and Bequeral Crater (see Oxia Palus NE, Site 148, ref.  

17), have floor deposits that could be evaporites, inclusive of 

carbonates.  Evaporite minerals possess characteristic spectral 

signatures in the infrared (15) and could similarly be identified 

from Mars orbit using high resolution remote sensing methods.  

Clearly, utilization of TES data will be important for optimizing 

site selection for Exopaleontology, and every effort should be 

made to benefit from that data before a final decision is made.



References



(1)	Allison, P.A.  and Briggs, D.E.G.  (1991) In Alison, P.A.  

and Briggs, D.E.G.  (eds.) Taphonomy:  Releasing the Data of the 

Fossil Record.  Plenum Press, New York, p.  25-70; Allison, P.A., 

and Pye, K.  (1994) Palaios 9, 561-575; Knoll, A.H.  (1984) Phil.  

Trans.  Royal Soc., London 311B, 111-122



(2)	Stevens, T.O and McKinley, J.P.  (1996) Science 270, 450-454



(3)	Clifford, S.M.  (1993) J. Geophys. Res.  88, 2456-2474



(4)	Christensen, P.R., Anderson, D.L., Chase, S.C., Clark, R.  

N., Kieffer, H.H., Malin, M.C., Pearl, J.C., Carpenter, J., 

Bandiera, N., Brown, F.G. and Silverman, S.  (1992) J. Geophys. 

Res.  97, 7719-7734



(5)	Walter, M.R., Des Marais, D.J.  (1993) Icarus 101, 129-143; 

Farmer, J.D., and Des Marais, D.J.  (1994) Lunar Planet. Sci.  25, 

367-368



(6)	Farmer, J.D.  (1996) In Bock, G. and Goode, J. (eds.) 

Evolution of Hydrothermal Ecosystems on Earth (and Mars?).  Wiley, 

Chichester, 273-299



(7)	Goldspiel J.M.  and Squyres, S.W.  (1991) Icarus 89, 392-410; 

Scott, D.H., Rice, J.W., Jr., and Dohm, J.M.  (1991) Orig. Life 

Evol. Biosph.  21, 189-198; Chapman, M.G.  (1994) Icarus 109, 393-

406; Landheim, R., Cabrol, N., Greeley, R., and Farmer, J.D.  

(1994) Lunar Planet. Sci.  25, 769-770; Farmer, J., Des Marais, 

D., Greeley, R., Landheim, R. and Klein, H.  (1995) Adv. Space 

Res. 15(3), 157-(3)162



(8)	Baker, V.R., Strom, R.G., Gulick, V.C., Kargel, J.S., 

Komatsu, G., and Kale, V.S.  (1991) Nature 352, 585-594



(9)	Schaefer, M.W.  (1993) Geochem. Cos. Acta 57, 4619-4625



(10)	Huntington, J.F.  (1996) In Bock, G. and Goode, J. (eds.) 

Evolution of Hydrothermal Ecosystems on Earth (and Mars?).  Wiley, 

Chichester, 214-230



(11)	Goetz, A.F.H., Vane, G., Solomon, J.E, and Rock, B.N.  

(1985), Science 228, 1147-1153



(12)	Swayze, G.A., Clark, R.N., Sutley, S., Gallagher, A.  (1992) 

Third JPL Airborne Geosci.  Workshop, Volume 1:  AVIRIS, JPL 

Publication 92-14, 47-49



(13)	Kruse, F.A., Kierein-Young, K.S.  and Boardman, J.W.  (1990).  

Photogram.  Engin. Rem. Sens.  56, 83-92



(14)	Warren, J.K.  (1989) Evaporite Sedimentology:  The Importance 

of Hydrocarbon Accumulation.  Prentice-Hall, New Jersey, 285 p.



(15)	Crowley, J.K.  (1993) Rem. Sens. Environ.  44, 1-25



(16)	Williams, S.H., and J.R.  Zimbelman.  (1994) Geology 22, 107-

110



(17)	Greeley, R. and Thomas, P. (eds.) (1994) Mars Landing Site 

Catalog.  (2nd Ed.) NASA Ref. Publ. 1238, 392 p.

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



MARS EXPLORATION STUDIES OF JBIS--BOOK REVIEW

by Julian Hiscox



Title:  Mars Exploration Studies of the Journal of the British

Interplanetary Society, 1989-1997.



Editor:  Robert Zubrin.



Volume 91:  Precursors and Early Piloted Missions.

Pages:  388.

ISBN:  0-87703-426-5 (Hard cover $70.00).

	  0-87703-427-3 (Soft cover $33.75).



Volume 92:  Base building, Colonisation and Terraformation.

Pages:  376.

ISBN:  0-87703-428-1 (Hard cover $70.00).

	  0-87703-429-X (Soft cover $45.00).



Obtainable from:  Univelt Incorporated, PO Box 28130, San Diego, 

California 92198-0198, USA.  Tel:  (760) 746-4005.  Fax:  (760) 

746-3139.



Nearly thirty years have passed since Neil Armstrong and Eugene 

"Buzz" Aldrin became the first humans to set foot on another 

world.  However, gone are the predictions of the early space 

pioneers, like Werner von Braun for huge orbiting space stations, 

Lunar bases and gargantuan missions to Mars.  Instead our presence 

in space is restricted to a semi-reusable space shuttle, space 

station Mir, and the soon to be assembled International Space

Station.  Whilst this is not meant to undo the wonderful 

achievements of both manned and unmanned space programs, the 

visions of yesteryear are often so different to the practicalities 

of today.  Perhaps one of the overriding factors in accomplishing 

these realities is cost, which in turn affects political will.



We can go to Mars with today’s technology, that is if we take the 

things with us required to bring everything back, but the cost 

involved is prohibitive in today’s fiscal climate, $540 billion at 

the last count.  What is required is a way to reduce the cost of 

the mission to manageable proportions, whilst retaining safety and 

worthwhile scientific goals.  This can be achieved by adopting new 

mission architectures perhaps adopting NASA’s philosophy of 

quicker, cheaper, better.  How can this be achieved?  The 

explorers of the 18th and 19th centuries provide a useful 

parallel.  Instead of taking all of the supplies necessary for a 

round trip voyage with them, they relied upon restocking along the 

way.  This is possible with travelling to and from Mars.  Unlike 

the Moon, all the resources needed to support life are available 

in some form on the surface of Mars and these resources can be 

used to facilitate human exploration of the Martian surface.  From 

Imagination to Reality:  Mars Exploration Studies of the Journal 

of the British Interplanetary Society is a collection of papers 

about Mars exploration and possible colonization.  They form part 

of the comprehensive American Astronautical Society’s Science and 

Technology Series.  (Details of this series, which contains the 

proceedings of the Case for Mars Conferences, can be accessed via 

the World Wide Web http://univelt.staigerland.com).  The papers 

were originally published in the Journal of the British 

Interplanetary Society (JBIS) and have been subject to peer 

review.  Volume 91, Section One contains 11 articles on Martian 

precursor missions, including sample return missions, in situ 

resource utilisation on Mars, e.g. propellant and oxygen 

production, and rockets for use in Mars ascent vehicles.  Included 

is an outline by Robert Zubrin of a possible first step in the 

human exploration--Athena, which is an Apollo 8 type mission, i.e.

to orbit around Mars.  Section Two also contains 11 articles, but 

focuses on early piloted missions, including human aspects such as 

the radiation and micro-gravity affects on human health of a round 

Mars trip.  An incremental approach to Mars exploration is 

eloquently argued by Geoffrey Landis (NASA Lewis Research Center) 

rather than a one off "flags and foot prints" mission.  Zubrin’s 

Mars Direct proposal forms the main idea of getting humans to Mars 

and returning them safely to Earth.  In this proposal the cost of 

going to Mars is greatly reduced by utilising Martian resources, 

the technologies for which have been logically discussed in 

Section One.



Volume 92, Section One, contains 11 articles which detail the 

setting up of a scientific outpost on Mars--superficially similar 

to those found in Antarctica.  Again Martian resource utilisation 

is a major focus.  Included is a discussion on closed 

environmental life support systems (CELSS), which as the name 

suggests, will surely provide the corner stone for long duration 

space missions.  Section Two contains 8 rather more speculative 

articles on Martian colonisation and the possibilities of altering 

the martian climate to more earth life conditions--popularly known 

as terraforming.  This section details the economic, 

technological, ethical and biological aspects of terraforming 

Mars.  The only notable absences, which might have been included 

in this section, were Martyn Fogg’s detailed papers on the 

technological problems of terraforming Mars and their possible 

solutions.



In summary, these two volumes read like a blue print for Mars 

exploration, and the reviewer thoroughly recommends them to those 

interested in Martian exploration.  Although of a technological 

nature, the ideas presented in the papers are easily digestible.  

Over the years the ideas published in JBIS have contributed to 

space flight.  I hope that many of the proposals presented in 

these two books will come to fruition.

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NEW MITIGATION STRATEGY MINIMIZES RISK OF ASTEROID COLLISIONS

University of Illinois release



4 April 1998



The spectacular plunge of Comet Shoemaker-Levy 9 into Jupiter in 

July 1994 and recent concern about the projected "near miss" of 

Asteroid 1997 XF11 with Earth in October 2028 brought renewed 

awareness that collision events do occur within our solar system--

and the next one could involve our planet.  In fact, such a 

collision may be long overdue, and steps should be taken to 

alleviate the risk, a University of Illinois researcher says.



"If faced with this kind of danger, we would want to send a 

spacecraft to intercept the object as far from Earth as possible," 

said Bruce Conway, a professor of aeronautical and astronautical 

engineering.  "This would allow whatever mitigation strategy we 

use to have the longest time to act."



There are two practical problems that must be solved, however, 

Conway said.  "The first is simply getting a sizable payload to 

the object in the shortest amount of time, and the second is 

deciding what to do when we get it there."



In a paper published in the September-October (1997) issue of the 

Journal of Guidance, Control, and Dynamics, Conway described the 

optimal low-thrust interception of a potential collider.  The 

proposed mission scenario would combine the speed of conventional 

chemical rockets with the increased payload capability of 

continuous-thrust electric propulsion.  Having arrived at the 

destination, however, what should be done to prevent the impending 

collision?



"For years, we assumed that the best mitigation strategy was to 

blow up the object with a nuclear warhead," Conway said.  "But 

that may not be such a good idea.  If we blow it up, instead of 

having just one large mass hurtling toward the Earth, we could end 

up with a multitude of smaller--but equally lethal--objects coming 

at us.  A better alternative would be to deflect the object."



One possible mechanism to accomplish this would involve detonating 

a nuclear warhead above the asteroid surface, Conway said.  "That 

would create a crater, and a large portion of the jet of vaporized 

material would shoot off in one direction--like a rocket--and push 

the object in the opposite direction."



But which direction should the object be pushed to ensure that it 

will miss the Earth?  And would it make more sense to speed the 

object up or slow it down?



Conway's latest research has focused on answering these questions.  

He developed an analytical method that, given the orbital 

parameters of the object and the interval between interception and 

close approach, determines the proper direction in which to push 

the object to maximize the deflection in the required time.  Such 

calculations may never be needed, but they're nice to have just in 

case.



"While the probability of a large asteroid or comet colliding with 

the Earth is low, the potential for destruction is immense," 

Conway said.  "It's probably not something we should lose sleep 

over; but, on the other hand, it would be really silly not to do 

anything."

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INCREASING GREENHOUSE GASES MAY BE WORSENING ARCTIC OZONE 

DEPLETION AND MAY DELAY OZONE RECOVERY

NASA release:  98-58



In late 1997, larger levels of ozone depletion were observed over 

the Arctic than in any previous year on record.  Now, using 

climate models, a team of scientists reports why this may be 

related to greenhouse gases, according to a paper published in the 

April 9 issue of Nature.



The study suggests the increase in greenhouse gas emissions is one 

possible cause of the observed trends in Arctic ozone losses and 

that this may delay recovery of the ozone layer.  The research 

team, consisting of researchers from NASA's Goddard Institute for 

Space Studies (GISS) and Columbia University, New York, 

investigated the response of ozone to projected future emissions 

of greenhouse gases and ozone-depleting halogens over time, using 

the GISS climate model.  This is the first time ever that the 

interaction between ozone chemistry and the gradual buildup of 

greenhouse gases has been studied in a climate model.



"Buildup of greenhouse gases leads to global warming at the 

Earth's surface, but cools the stratosphere.  Since ozone 

chemistry is very sensitive to temperature, this cooling results 

in more ozone depletion in the polar regions," said Dr. Drew 

Shindell of Columbia University, the lead author of the study.  

NASA will continue research in this area to determine if these 

models are accurate.



The "greenhouse effect" is defined as the warming of climate that 

results when the atmosphere traps heat radiating from Earth toward 

space.  Certain gases in the atmosphere--such as water vapor, 

carbon dioxide, nitrous oxides and chlorofluorocarbons--act like 

glass in a greenhouse, allowing sunlight to pass into the 

"greenhouse," but blocking Earth's heat from escaping into space.



Ozone, a molecule made up of three atoms of oxygen, comprises a 

thin layer of the upper atmosphere which absorbs harmful 

ultraviolet radiation from the Sun and protects people, animals 

and plants from too much ultraviolet sunlight.



Distribution and concentration of stratospheric ozone are 

influenced in two ways by human-driven activity in addition to 

natural, seasonal variations.  Of first importance is the direct 

impact of industrially produced chlorofluorocarbons.  Although 

ozone levels around the globe are expected to continue to decline 

over the next several years, NASA is now detecting decreasing 

growth rates of ozone-depleting compounds in the upper part of the 

atmosphere, indicating that international treaties to protect the 

ozone layer are working.  The second influence on stratospheric 

ozone levels is the indirect impact of "greenhouse gases" on 

atmospheric temperatures.  Ozone destruction is quite sensitive to 

temperature increases in the atmosphere.



Since upper atmospheric temperatures in the Northern Hemisphere 

during winter and spring generally are warmer than those in the 

Southern Hemisphere, ozone depletion over the Arctic has been much 

smaller than over the Antarctic during the 1980s and early 1990s.  

The Arctic stratosphere, however, gradually has cooled over the 

past few decades resulting in very large ozone depletion, 

especially during 1996-97.



In the simulations performed by Shindell and his team, temperature 

and wind changes, induced by increasing greenhouse gases, clearly 

alter the dynamics of the atmosphere.  According to this model, as 

the abundance of greenhouse gases gradually increases, the 

frequency of Northern Hemisphere sudden stratospheric warming is 

reduced, leading to significantly colder lower stratospheric 

temperatures.  If proven correct, this dynamic effect would add to 

the greenhouse cooling of the stratosphere.



"Results suggest that the combination of these two cooling effects 

causes dramatically increased ozone depletion so that ozone loss 

in the Arctic by the year 2020 roughly is double what it would be 

without greenhouse gas increases," said Dr. David Rind of GISS, a 

co-author of the paper.  Increasing greenhouse gases therefore may 

be at least partially responsible for the very large Arctic ozone 

losses in recent winters.



The authors caution, however, that though the model predicts a 

general trend towards increasing ozone depletion, the year-to-year 

variability is quite large, especially in the Arctic.  For 

example, several years in the late 1990s and early 2000s show very 

little Arctic ozone depletion, while others show record losses.  

In fact, the 1997-98 winter that just occurred was characterized 

by significantly less ozone loss than the preceding six winters.  

A factor that should be considered, however, is the consistency in 

model predictions, i.e. whether other models can reproduce the 

same results.



According to this model, the severity and duration of the 

Antarctic ozone depletion also may increase due to greenhouse gas-

induced stratospheric cooling over the coming decades.  However, 

ozone in the Antarctic is already so depleted that any additional 

losses may be relatively small, Rind added.



The research was conducted by scientists at GISS, The Center for 

Climate Systems Research, Columbia University, and Science Systems 

and Applications Inc., New York.  The GISS research is part of 

NASA's Earth Science Enterprise, a long-term coordinated research 

effort to study the Earth as a global system.

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GLOBAL SURVEYOR SCHEDULES IMAGING OPPORTUNITIES FOR VIKING, 

PATHFINDER, CYDONIA REGIONS OF MARS

JPL release



31 March 1998



The Mars Global Surveyor project has resumed scientific 

observations of the surface of Mars and has scheduled 

opportunities to image four selected sites:  the Viking 1 and 2 

landing sites, the Mars Pathfinder landing site and the Cydonia 

region.



Three opportunities to image each of the four sites using the 

spacecraft's high-resolution camera will take place over the next 

month, beginning on April 3 at 1:58 a.m.  Pacific time, when 

Global Surveyor passes over the Viking 1 landing site.  The 

spacecraft will next pass over the Viking 2 landing site at 1:37 

p.m. Pacific time on April 3.  On April 4, Global Surveyor will 

try to image the now-silent Mars Pathfinder spacecraft at 1:16 

a.m. Pacific time.  It will then capture a portion of the Cydonia 

region of Mars, location of the so-called "Face on Mars," on April 

5 at 12:33 a.m. Pacific time.



Attempts to rephotograph the sites will occur during two 

additional opportunities falling about nine days apart.  A 

detailed schedule of the imaging attempts is listed below.  

Uncertainties in both the spacecraft's pointing and the knowledge 

of the spacecraft's ground track from its navigation data will 

provide only a 30- to- 50-percent chance of capturing the images 

of each site.



All of the selected targets are located south of Global Surveyor's 

periapsis, or point of closest approach to the Martian surface.  

Shortly before the spacecraft reaches this point, the Global 

Surveyor spacecraft will rotate slightly so that when it nears the 

selected target, the camera's field-of-view will sweep across the 

target as the spacecraft flies south and rises away.



The spacecraft will begin transmitting to Earth data stored on its 

onboard solid-state recorders about seven hours after the images 

are acquired, concluding about three hours later.  Currently it 

takes radio signals from Mars Global Surveyor about 20 minutes to 

travel from the spacecraft to Earth.



Data will be received at one of NASA's Deep Space Network tracking 

stations at Goldstone, CA, near Madrid, Spain or near Canberra, 

Australia, and then sent by satellite to NASA's Jet Propulsion 

Laboratory, Pasadena, CA.  There the images, along with all of the 

rest of Global Surveyor's science and engineering data, are placed 

in the project database for access by flight controllers.  This 

process takes only seconds for each bit of data.  Consequently, 

the image data will not be available be on the ground until about 

10.5 hours after they are acquired.  Data received overnight will 

not be retrieved until 9 a.m. Pacific time on the following 

workday.



When camera operators retrieve image data, the information is 

assembled into "raw" images.  Raw images may contain data errors 

or drop-outs introduced by noise in the telecommunications channel 

between the spacecraft and the ground, as well as very slight 

picture element variations inherent in the camera.  This data 

processing takes about 30 minutes.



Raw images will posted on three web sites:  JPL's Mars news site 

at http://www.jpl.nasa.gov/marsnews , the Mars Global Surveyor 

project home page at http://mars.jpl.nasa.gov , and NASA's 

Planetary Photojournal site at http://photojournal.jpl.nasa.gov.  

Information identifying the acquisition time, predicted center 

latitude and longitude of the target location, and the local solar 

time will accompany these images.  Contrast enhancement will be 

performed by JPL's Multimission Image Processing Laboratory and 

posted on World Wide Web a few hours later.  The Global Surveyor 

project home page also contains spacecraft orbital velocity and 

distance to the planet in real time.



Images of the Viking and Mars Pathfinder landing sites will not be 

posted until image enhancement and identification of the vehicles 

have been completed, because the small spacecraft will be at the 

limits of the camera's resolution.  This process will take about 

24 hours.



Mars Global Surveyor is part of a sustained program of Mars 

exploration known as the Mars Surveyor Program.  The Jet 

Propulsion Laboratory manages the mission for NASA's Office of 

Space Science, Washington, DC.  JPL's industrial partner is 

Lockheed Martin Astronautics, Denver, CO, which developed and 

operates the spacecraft.  JPL is a division of the California 

Institute of Technology, Pasadena, CA.

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



PROCESSED MARS GLOBAL SURVEYOR IMAGES OF THE CYDONIA REGION 

RELEASED

by Ron Baalke, JPL



Here are the processed Mars Global Surveyor images of the Cydonia 

region:



http://photojournal.jpl.nasa.gov/cgi-

bin/PIAGenCatalogPage.pl?PIA01236



This shows two strips of data, the raw image is on the left, and 

the processed image is on the right.  The "Face" is well lit and 

shows no deep shadows that was exhibited in the Viking images.  In 

the higher-resolution MGS image, the "Face" is just an ordinary 

looking hill, and with no shadows there are no facial features 

present at all.



In this image:

http://photojournal.jpl.nasa.gov/cgi-

bin/PIAGenCatalogPage.pl?PIA01237



The "Face" has been rotated to appear in the same orientation as 

the Viking image.  Again, nothing out of the ordinary.



The original Viking image is here:

http://photojournal.jpl.nasa.gov/cgi-

bin/PIAGenCatalogPage.pl?PIA01141



You can compare the Viking image with the Mars Global Surveyor 

image.  MGS took the image of the "Face" from a different viewing 

angle than Viking, but you can line up the nearby craters to see 

how they compare.

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



MARS ORBITER CAMERA VIEWS THE "FACE ON MARS"

From the Mars Global Surveyor home page

http://mars.jpl.nasa.gov/mgs/msss/camera/images/4_6_face_release/i

ndex.html



Shortly after midnight Sunday morning (5 April 1998 12:39 AM PST), 

the Mars Orbiter Camera (MOC) on the Mars Global Surveyor (MGS) 

spacecraft successfully acquired a high resolution image of the 

"Face on Mars" feature in the Cydonia region.  The image was 

transmitted to Earth on Sunday, and retrieved from the mission 

computer data base Monday morning (6 April 1998).  The image was 

processed at the Malin Space Science Systems (MSSS) facility 9:15 

AM and the raw image immediately transferred to the Jet Propulsion 

Laboratory (JPL) for release to the Internet.  The images shown 

here were subsequently processed at MSSS.



The picture was acquired 375 seconds after the spacecraft's 220th 

close approach to Mars.  At that time, the "Face", located at 

approximately 40.8° N, 9.6° W, was 275 miles (444 km) from the 

spacecraft.  The "morning" sun was 25° above the horizon.  The 

picture has a resolution of 14.1 feet (4.3 meters) per pixel, 

making it ten times higher resolution than the best previous image 

of the feature, which was taken by the Viking Mission in the mid-

1970's.  The full image covers an area 2.7 miles (4.4 km) wide and 

25.7 miles (41.5 km) long.



Weather Conditions at the Time of Imaging



Winter clouds cover much of the northern hemisphere of Mars above 

40° N latitude at this time of the martian year.  An image of the 

Viking Lander 2 site (at 44° N) taken just over a day ago was 

completely obscured by clouds.  The image below shows a color 

composite made from the red and blue wide angle cameras (the green 

component is synthesized from the average of the red and blue 

frames).  The small box marks the location of the high resolution 

image.  As can be seen, fortuitously, the area imaged was 

relatively clear, although the lack of surface definition in many 

nearby areas, and the low contrast of the raw MOC high resolution 

image, suggests haze or fog over much of the area.



[Image]

Color Wide Angle Image of Cydonia taken at same time as High 

Resolution

Image

654 KB JPEG



Location Images



The first two images below this paragraph are the best Viking 

pictures of the area in Cydonia where the "Face" is located.  For 

more information about the "Face" and the Viking images, see

http://www.msss.com/education/facepage/face.html.  Marked on the 

two images is the "footprint" of the high resolution (narrow 

angle) camera.  Also marked on the second of the images is a 

dashed box outlining the area seen in enlarged views.



The third view is a one-quarter scale version of the full MOC 

image, presented to show the "Face" in relation to the features in 

its immediate vicinity.  This image has been processed to enhance 

features and project it into a mercator map perspective.



[Image]

035a72.map

1.68 MB



[Image]

070a13.map

1.64 MB



[Image]

Full swath at 1/4th resolution

1.12 MB



Raw and Raw stretched



The images below this paragraph are portions of the raw image, and 

a slightly contrast enhanced version of the raw image, that 

include the "Face."  The full raw image can be retrieved from the 

JPL WWW site by selecting either the MGS icon (the upper right of 

the four icons shown on that page) or by going to one of the many 

JPL Mars mirror sites.



NOTE:  The raw images shown immediately below (and on the JPL 

site) are flipped left to right from the others shown on this page 

because of the scan direction of the camera.  All other images 

shown have had their orientation corrected for this scan 

relationship.



[Image]

Section of raw image

584 KB



[Image]

Contrast enhanced raw image

584 KB



Processing



Image processing has been applied to the images in order to 

improve the visibility of features.  This processing included the 

following steps:



1.	The image was processed to remove the sensitivity differences 

between adjacent picture elements.  This removes the vertical 

streaking.



2.	The contrast and brightness of the image was adjusted, and 

"filters" were applied to enhance detail at several scales.



3.	The image was then geometrically warped to meet the computed 

position information for a mercator-type map.  This corrected for 

the left-right flip, and the non-vertical viewing angle (about 45° 

from vertical), but also introduced some vertical "elongation" of 

the image for the same reason Greenland looks larger than Africa 

on a mercator map of the Earth.



4.	A section of the image, containing the "Face" and a couple of 

nearly impact craters and hills, was "cut" out of the full image 

and reproduced separately, as seen below.



For additional information on image processing, see:



http://www.msss.com/education/facepage/vikingproc.html.



[Image]

Calibrated, mercator map-projected (flipped left to right), 

contrast

enhanced, filtered

543 KBytes



[Image]

Brightness-inverted (dark to light) version of calibrated, 

mercator map-projected (flipped left to right), contrast enhanced, 

filtered

573 KB



[Image]

Just the "Face"

307 KB



Comparison of the Best Viking and Reduced Resolution MOC Images



In the comparison below, the best Viking image has been enlarged 

to 3.3 times its original resolution, and the MOC image has been 

decreased by a similar 3.3 times, creating images of roughly the 

same size.  In addition, the MOC images have been geometrically 

transformed to a more overhead projection (different from the 

mercator map projection of the preceding images) for ease of 

comparison with the Viking image.  The left image is a portion of 

Viking Orbiter 1 frame 070A13, the middle image is a portion of 

MOC frame 22003 shown normally, and the right image is the same 

MOC frame but with the contrast reversed (that is, light features 

were forced to be dark, and dark features were forced to be light) 

to simulate the approximate lighting conditions of the Viking 

image.



[Image]

Comparison of best Viking with two versions of MOC image

415 KB



Malin Space Science Systems and the California Institute of 

Technology built the MOC using spare hardware from the Mars 

Observer mission.  MSSS operates the camera from its facilities in 

San Diego, CA.  The Jet Propulsion Laboratory's Mars Surveyor 

Operations Project operates the Mars Global Surveyor spacecraft 

with its industrial partner, Lockheed Martin Astronautics, from 

facilities in Pasadena, CA and Denver, CO.

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



EDINBURGH SCIENTISTS BID TO JOIN NASA "LIFE IN THE UNIVERSE" STUDY

by Jacqueline Mitton, Royal Astronomical Society



In response to an initiative from NASA, a group of Edinburgh 

geologists, biologists and astronomers hoping to participate in 

the new NASA Astrobiology Institute (NABI) have formed the 

Edinburgh Astrobiology Consortium.  On Tuesday 31st March, Dr. Ray 

Wolstencroft of the Royal Observatory Edinburgh, will tell the 

National Astronomy Meeting at the University of St Andrews about 

the research the group want to do.



"Astrobiology is a huge subject," says Dr. Wolstencroft.  "You can 

probably best describe it as 'the study of life in the universe'.  

Interest in astrobiology is growing rapidly thanks to the recent 

discoveries of planets around nearby stars, possible though 

controversial evidence of fossils in a Martian meteorite and the 

accumulating evidence that terrestrial organisms can thrive in a 

wide variety of extreme environments.  NASA is keen to encourage 

much more research in astrobiology."



"A major goal for NASA is to develop an understanding of whether 

there is life elsewhere other than on Earth, where life may be 

found and how best to detect it.  NASA is also interested in how 

terrestrial organisms may adapt and evolve in extraterrestrial 

environments.  All this needs teams of researchers including 

international experts in different areas of science."



The Astrobiology Institute will be a "virtual institute" of 

geographically separate research groups located around the world 

and will be managed by the NASA Ames Research Center in Mountain 

View California.  To overcome the difficulties of such widely 

separated groups working together, the Institute is experimenting 

with advanced electronic connections based on the Next Generation 

Internet.



The work proposed by the Edinburgh Astrobiology Consortium(EAC) 

includes:



* Very remote sensing of vegetation on Earth-like planets



* Theoretical studies of photosynthesis on Earth-like planets 

orbiting stars hotter or cooler than the Sun



* Early development of life on the Earth



* Evolution of primordial bacteria from deep ocean sediments.



The EAC members are:



* Ray Wolstencroft, Alistair Glasse, Mark Casali (Royal 

Observatory Edinburgh)



* Paul Jarvis (Dept of Forestry and Natural Resources, University 

of Edinburgh)



* John Raven (Dept of Biological Sciences, University of Dundee)



* Francois-Marie Breon (Laboratoire du Climat, Paris)



* Nicholas Barton, William Hill, Andy Leigh-Brown (Institute of 

Cell, Animal and Population Biology, University of Edinburgh)



* Dick Kroon (Dept of Geology and Geophysics, University of 

Edinburgh)



* Colin Graham (Dept of Geology and Geophysics, University of 

Edinburgh)



* Andrew Lawrence (Institute of Astronomy, University of 

Edinburgh)



The Edinburgh proposal is one of 70 submitted to NASA from groups 

around the world, and the Consortium is waiting to hear whether 

its bid has been successful.



Contact for Further Information:  Dr Ray Wolstencroft, Royal 

Observatory, Blackford Hill, Edinburgh EH9 3HJ.  Tel 0131 668 

8307; FAX 0131 662 1668 E-mail:  R.Wolstencroft@roe.ac.uk

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



SHUTTLE MISSION'S "NEUROLAB" TO STUDY NERVOUS SYSTEM

NSF release



7 April 1998



Science in Space to Feature Snails, Fish



Early on the morning of April 16, 1998, dozens of snails and fish 

will go where only a few men and women have gone before--into 

outer space.  The snails and fish will travel aboard NASA's Space 

Shuttle Columbia, as part of a research project funded by the 

National Science Foundation (NSF) to study the development of 

gravity sensors in space by animals in the early stages of life.



The snails and fish will fly aboard Neurolab, a shuttle research 

mission dedicated to the study of the life sciences.  Neurolab 

will focus on the most complex and least understood part of the 

human body--the nervous system--that faces major challenges in 

space.



Gravity sensing systems have the same basic structure in all 

vertebrates, whether fish or humans.  The gravity-detecting organ 

is lined with sensory cells that send signals to the brain when 

they are "triggered" by small, rock-like particles of calcium 

carbonate, referred to as statoliths in snails and otoliths in 

fish (and in humans).  In humans, this system is a component of 

the inner ear.



"Gravity is always present on earth, so it's been hard to explore 

its role in development and in controlling movement," says 

Christopher Platt, program manager in NSF's division of 

integrative biology and neuroscience, which funded the aquatic 

experiments.  "Neurolab allows unique tests that will shed light 

on how gravitational sensors work.  These studies may tell us how 

exposure to lack of gravity may lead to abnormalities in the 

otolith organs, relevant to long-term space flight and to certain 

kinds of posture and balance problems in people on Earth."



Other benefits of the aquatic studies aboard Neurolab are 

development of an electrode that offers potential use as a 

connection to the nervous system in people with deafness caused by 

hair cell damage.  The electrode might also someday be used as an 

interface to signal motor prostheses how and when to move.



Tracking the progress of the snails and fish flying aboard 

Columbia will be scientists on The Aquatic Team, as they're known 

to shuttle crewmembers.  Researcher Michael Wiederhold of the 

University of Texas Health Science Center at San Antonio will 

monitor freshwater snails and swordtail fish in the beginning 

stages of their development into adults.



Wiederhold hopes to learn what physiological changes occur in the 

components of the gravity sensors of animals in space, whether 

signals sent from the inner ear to the brain are altered, and if 

alterations do occur, whether behavior of the animal changes.  

Upon return from their flight in space in Neurolab, the freshwater 

snails and swordtail fish will be compared to a control group on 

Earth to determine whether the size of their statoliths and 

otoliths increased while they were in "microgravity."  On Earth, 

the pull of gravity eventually signals developing statoliths and 

otoliths to stop growing.  "In space, however," says Wiederhold, 

"without this signal, they should develop to a larger size than 

they do on Earth.  And if indeed they increase in size, how will 

that affect these animals?"



Scientist Steven Highstein of the Washington University School of 

Medicine in St. Louis, Missouri, will also study aspects of the 

inner ear, but his research involves the inner ears of astronauts 

flying aboard Columbia, as well as those of oyster toadfish aboard 

Neurolab.

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JPL EVENING LECTURES HIGHLIGHT EARTH EXPLORATION MISSIONS

JPL release



7 April 1998



"The Earth Observer:  Understanding Our Planet from 400 Miles Up" 

will be the theme for two free public lectures, one on Thursday, 

April 16 at 7 p.m. in JPL's von Karman Auditorium, the other on 

Friday, April 17 at 7 p.m. in The Forum at Pasadena City College.  

Seating is limited and will be on a first-come, first-served 

basis.



The lectures will be presented by Marguerite Syvertson, outreach 

coordinator for the Earth Science Flight Experiments Program and 

the Earth and Space Sciences Division.  She has been involved as 

an engineer, scientist and outreach specialist in the development 

of the Earth Observing System (EOS).



Over the next decade, NASA is preparing to launch a suite of 

missions that will greatly aid in a more comprehensive 

understanding of Earth and its processes.  The Earth Observing 

System AM-1 satellite, scheduled for launch this summer, is the 

first of these missions and will provide unprecedented amounts of 

data about Earth's surface, oceans and atmosphere that will allow 

scientists to study and eventually model changes in Earth's 

environment and climate.



EOS AM-1 will carry two instruments onboard:  the Multi-Angle 

Imaging Spectroradiometer (MISR) and the Advanced Spaceborne 

Thermal Emission and Reflection Radiometer (ASTER), which is 

provided by Japan's Ministry of International Trade and Industry 

with scientific support provided by JPL.  These instruments will 

monitor Earth's biosphere, volcanoes, oceans and clouds.



Two more spacecraft, one carrying the Atmospheric Infrared Sounder 

(AIRS), which will study weather and climate, and the other 

carrying the Microwave Limb Sounder (MLS) and the Tropospheric 

Emission Specrometer (TES), will study atmospheric composition and 

will be launched in 2000 and 2002 respectively.



This lecture is part of the von Karman Lecture Series sponsored 

monthly by the JPL Media Relations Office.  A web site on the 

lecture series is located at http://www.jpl.nasa.gov/lecture.  For 

directions and other information, call the Media Relations Office 

at (818) 354-5011.

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SCIENCE TEAM CHOSEN FOR TECHNOLOGY VALIDATION MISSION TO EXPLORE 

THE SUBSURFACE OF MARS

NASA release 98-59



Nine researchers have been selected to be the Science Team for the 

Mars Microprobes, a technology validation mission that will 

hitchhike to the red planet aboard NASA's 1998 Mars Polar Lander 

mission.



Two identical probes will be carried as a secondary payload on the 

lander, due for launch in January 1999.  Following an 11-month 

cruise, the Microprobes will separate from the lander before it 

enters the Martian atmosphere, and then hit the ground at 

approximately 400 mph.



During the impact, each microprobe will separate into two 

sections:  the forebody and its instruments will penetrate up to 

six feet (two meters) below the surface, while the aftbody will 

remain near the surface to communicate with a radio relay on 

NASA's Mars Global Surveyor orbiter while making meteorological 

measurements.



The nine selected scientists are:

* David Catling, NASA Ames Research Center, Moffett Field, CA * 

Ralph Lorenz, University of Arizona, Tucson

* Julio Magalhaes, NASA Ames Research Center * Jeffrey Moersch, 

NASA Ames Research Center * Paul Morgan, Northern Arizona Univ., 

Flagstaff * James Murphy, NASA Ames Research Center

* Bruce Murray, California Institute of Technology, Pasadena * 

Marsha Presley, Arizona State Univ., Phoenix

* Aaron Zent, NASA Ames Research Center



The scientific objectives of the Mars Microprobes include 

searching for the presence of water ice in the soil and 

characterizing its thermal and physical properties.  A small drill 

will bring a soil sample inside the probe, heat it, and look for 

the presence of water vapor using a tunable diode laser.  An 

impact accelerometer will measure the rate at which the probes 

come to rest, giving an indication of the hardness of the soil and 

any layers present.  Temperature sensors will estimate how well 

the Martian soil conducts heat, a property sensitive to different 

soil properties such as grain size and water content.  A sensor at 

the surface will measure atmospheric pressure in tandem with a 

sensor on the Mars Polar Lander.



The Mars Microprobes mission, also known as Deep Space-2 (DS-2), 

is scheduled to be the second launch in NASA's New Millennium 

Program of technology validation flights, designed to enable 

advanced science missions in the 21st century.



"I'm delighted with the selection of this excellent group of 

investigators.  The Mars Microprobe will give us a glimpse of the 

subsurface of Mars, which in many ways is a window into the 

planet's history," said Dr. Suzanne Smrekar, the DS-2 project 

scientist at NASA's Jet Propulsion Laboratory, Pasadena, CA.  "The 

region of Mars we will explore is similar to Earth's polar regions 

in that it is believed to collect ice and dust over many millions 

of years.  By studying the history of Mars and its climate, we are 

likely to better understand the more complex system on our own 

planet."



In addition to the miniaturized science instruments capable of 

surviving high velocity impact, technologies to be tested on DS-2 

include a non-erosive, lightweight, single-stage atmospheric entry 

system or aeroshell; power microelectronics with mixed 

digital/analog advanced integrated circuits; an ultra-low 

temperature lithium battery; an advanced three-dimensional 

microcontroller; and flexible interconnects for system cabling.



"The combination of a single-stage entry vehicle with electronics 

and instrumentation that can survive very high impact loads will 

enable us to design a whole new class of very small, rugged 

spacecraft for the in-situ exploration of the planets," explained 

Sarah Gavit, DS-2 project manager at JPL.



"Slamming high-precision science instruments into the surface of 

Mars at 400 mph is very challenging, no doubt about it!  But once 

this type of technology is demonstrated, we can envision future 

missions that could sample numerous regions on Mars or make 

network measurements of global weather and possible Marsquakes," 

said DS-2 program scientist Dr. Michael Meyer of NASA 

Headquarters, Washington, DC.



Further information on DS-2 is available on the Internet at the 

following URL:  http://nmp.jpl.nasa.gov/ds2/



The New Millennium Program is managed by JPL for NASA's

Office of Space Science in Washington, DC.  JPL is a division of 

the California Institute of Technology, Pasadena, CA.

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



MARS GLOBAL SURVEYOR FLIGHT STATUS REPORTS

JPL releases



27 March 1998



Nearly six months of aerobraking operations concluded today as the 

flight team raised the low point of Surveyor's orbit out of the 

Martian atmosphere.  This maneuver was accomplished shortly after 

1:00 a.m. PST as the spacecraft's onboard flight computer 

commanded the main rocket engine to fire for 6.6 seconds.  The 

burn occurred at the high point of the 201st orbit and raised the 

low point of the orbit from 77.7 miles (125.0 km) up to 106.0 

miles (170.6 km).



"From my point of view, it was an excellent execution of the 

maneuver," commented Surveyor's navigation chief, Dr. Pat 

Esposito.  According to the navigation team, the burn altered the 

spacecraft's velocity by 9.8 miles per hour (4.4 meters per 

second) and was precisely executed.  Compared to the original 45-

hour orbit after arrival at the red planet last September, this 

post-aerobraking orbit takes 11 hours, 38 minutes, and 38 seconds 

to complete.



Later in the afternoon on the 202nd orbit, the flight team 

transmitted commands to activate the science payload.  At this 

time, active instruments include the Magnetometer, Mars Orbiter 

Camera, and the Mars Orbiter Laser Altimeter.  The Thermal 

Emission Spectrometer will be activated the week of March 29th.  

In addition, the radio science team continues to collect data 

about Mars' gravity and atmosphere by analyzing the radio signals 

that Surveyor transmits back to Earth.



For the next five months, the temporary aerobraking hiatus will 

allow the science teams to collect data near the low point of 

every orbit.  Aerobraking will resume on September 11th with the 

goal of reducing the orbit period to less than two hours by 

February 1999.  The current hiatus is necessary so that Mars will 

be in the proper position in its orbit around the Sun when mapping 

commences next spring.



Some of the payload activity highlights this month include 

measurements of the thickness of the north polar ice caps by the 

laser altimeter, and attempted targeting of the Viking 1, Viking 

2, and Mars Pathfinder landing sites by the camera.  Imaging of 

the Cydonia region, location of the so-called "face on Mars," will 

also be attempted.  Because targeting exact locations on the 

ground from orbit requires extreme precision, normal uncertainties 

in the spacecraft's position and pointing capability will limit 

the probability of success to between 30% to 50%.



After a mission elapsed time of 505 days from launch, Surveyor is 

222.10 million miles (357.43 million kilometers) from the Earth 

and in an orbit around Mars with a high point of 11,100 miles 

(17,865 km), a low point of 106.0 miles (170.6 km), and a period 

of 11.6 hours.  The spacecraft is currently executing the P203 

command sequence, and all systems continue to perform as expected.  

The next status report will be released on April 17th.



4 April 1998



10:00 AM PST



Mars Global Surveyor made its first attempt to target a specific 

location on the surface of Mars yesterday and missed the target 

very slightly.  The site of the Viking Lander 1 was the first 

target in the up coming set of four that will include Viking 

Lander 2, Mars Pathfinder and the Cydonia region.  Global Surveyor 

came rather close, but the landing site was about 150 meters (500 

feet) to the west of the edge of the long, narrow image that was 

to contain it.  The image was well centered in the north to south 

direction.  The width of the image was slightly greater than 5 km 

(3 miles).  The flight team will continue its analysis of the 

targeting performance.



The sequence of events for the imaging of Cydonia was loaded on 

board the spacecraft yesterday afternoon.  The detailed commands 

to control the imaging will be loaded in about 2 hours after the 

latest orbit determination has been completed.



4:00 PM PST



The Mars Global Surveyor flight team and camera operators may have 

been successful in placing the site of the Viking Lander 2 within 

the field of view of the MGS Mars Orbiter Camera on the second of 

four attempts to image sites of interest on the surface of Mars.  

Like the atmospheric conditions in Pasadena, CA, today, Utopia 

Planitia, the location of the Viking Lander 2, was heavily 

overcast when the image was recorded shortly in early afternoon, 

Pacific time, yesterday.  The Mars Orbiter Camera team reports 

that because of the surface obscuration, the location of the image 

with respect to surface features is problematic.  It is believed, 

however, that the Viking-era landing location and one of its more 

recently estimated locations are within the lower portion of the 

image.  Knowledge of the Viking Lander 2 site is the least well 

established of the targets that Global Surveyor is attempting to 

photograph.  Analysis of the results of these first images will 

help the project team with the future imaging attempts.



9 April 1998



Mars Global Surveyor has completed the first of three sets 

(clusters) of specially targeted imaging opportunities during its 

current hiatus in aerobraking.  While it was estimated that 

probability of successfully accomplishing this imaging would be on 

the order of 30-50% for each of the images, owing to navigation, 

spacecraft attitude control and map location uncertainties, it 

appears that we have done somewhat better.



On April 3, 1998, at 0958 UTC, MGS pointed the Mars Orbiter Camera 

toward the Viking Lander 1 site in Chryse Planitia.  The area was 

covered with a thin cloud layer and patchy thick clouds, reducing 

but not eliminating surface visibility.  The narrow angle image 

had relatively low contrast but the contrast was sufficient for 

adequate feature identification.  This analysis showed that the 

targeted spot for the Viking Lander 1 sites was approximately 40 

pixels or 150 m off the western edge of the image, although it was 

well centered in the north to south direction.  We came very 

close, and the pointing performance was well within the expected 

variations of the spacecraft's attitude control system, and we'll 

count this as a miss.  Because the Lander was not in the picture, 

we won't release the image at this time.



Viking Lander 2 is located in Utopia Planitia, further north and 

on the other side from Mars from Viking Lander 1.  When MGS imaged 

this area on April 3, at 2137 UTC, on the orbit following the 

Viking Lander 1 observation, it found the area in heavy overcast, 

with clouds and haze severely reducing the surface visibility by 

over 70-80%.  These clouds and possible surface frost led to a 

scene substantially brighter than anticipated, and thus much of 

the image data was saturated bright.  Aggressive application of 

image processing techniques enhanced faint brightness variations, 

rendering a small number of surface features visible.  These 

features were used to attempt to determine the success of the 

targeting.  It is believed that the Viking-era landing location 

may be with the extreme south-west portion of the image and the 

western-most of three new estimated positions, more recently 

determined, may be in the lower south-eastern portion of the 

image.  The location of Viking Lander 2 is the least well known of 

the sites being imaged.  So, we'll count this attempt as a hit, 

however, because the image is mostly clouds, we won't release it 

at this time.



Mars Pathfinder, the Sagan Memorial Station, and the Sojourner 

rover are located in Ares Vallis.  On April 4th, at 0916 UTC, the 

spacecraft was successful in targeting the point that it was 

directed to, however, a controversy has arisen as to the true 

coordinates of the real landing site.  It appears that, after some 

reevaluation of the targeting information used with the Mars 

Pathfinder project, we have used the wrong coordinate references 

for our target point.  Better information will be used in the next 

opportunity.  Because it appears that Mars Pathfinder is not in 

the image, we won't release the image at this time.



The feature known as the "Face on Mars" in the Cydonia region was 

imaged quite successfully on April 5th and its image was released 

in raw form and in an enhanced form on April 6th.  The picture was 

acquired 375 seconds after the spacecraft's 220th closest approach 

to Mars.  At that time, the "Face", located at approximately 40.8 

degrees N, 9.6 degrees W, was 275 miles (444 km) from the 

spacecraft.  The "morning" sun (about 10 AM local solar time) was 

25 degrees above the horizon.  The picture has a resolution of 

14.1 feet (4.3 meters) per pixel, making it ten times higher 

resolution than the best previous image of the feature, which was 

taken by the Viking Orbiter 1 in 1976.  The full image covers an 

area 2.7 miles (4.4 km) wide and 25.7 miles (41.5 km) long.



Since winter clouds cover much of the northern hemisphere of Mars 

above 40 degrees N latitude at this time of the Martian year, the 

raw image of the "Face" was of very low contrast, that is, 

variations in brightness of the picture elements cover a very 

small range compared to the ultimate capability of the camera.  

Thus, the "raw" image appears very dark and flat.  This very 

washed out appearance of the northern hemisphere of Mars can be 

readily seen in the wide angle image taken at the same time as the 

narrow angle picture that contains the "Face" (see

http://mars/mgs/msss/camera/images/4_6_face_release/index.html).  

The enhanced version of the raw data has made the feature visible.  

The enhanced version also flipped the image left to right to make 

it appear in the same orientation as the familiar Viking image.



The targeting was very good for this attempt and is clearly a hit.  

The "Face" was nearly exactly in the center of the image.  A 

portion of another feature in the area, the "D&M Pyramid", is the 

bottom left-hand corner of the image.



The Mars Surveyor Operations Project assesses the results of the 

first cluster of targeted imaging to have been quite successful.  

The results have provided information useful in fine-tuning the 

processes for the second cluster of images that will be taken 

starting on April 12th.



10 April 1998



The Mars Global Surveyor operations team is gearing up to begin 

imaging a second set of specifically targeted geologic features on 

Mars, after completing the first set of images last week and 

successfully capturing the so-called "Face on Mars."



At the direction of NASA Administrator Daniel Goldin, the flight 

team has developed a schedule of new targets.  On Tuesday, April 

14, Global Surveyor will image a second portion of the Cydonia 

region known as "The City."  This area of Cydonia contains 

geological features that have been referred to as "mounds," a 

"city square," "pyramids" and "the fortress."  The spacecraft's 

high-resolution camera will use the "city square" portion of this 

geologic formation as the target point.



The image will be posted on JPL's Mars news site at 

http://www.jpl.nasa.gov/marsnews, on the Mars Global Surveyor 

project home page at http://mars.jpl.nasa.gov, and on NASA's 

Planetary Photojournal site at http://photojournal.jpl.nasa.gov as 

soon as it is available.  This is expected to be by about mid- 

evening Pacific time on Tuesday, April 14.



Last week's attempts to image the landing sites of the Viking 1, 

Viking 2 and Mars Pathfinder landers were unsuccessful.  Global 

Surveyor will make new attempts to image the Viking sites on two 

consecutive orbits on Sunday, April 12.  On Monday, April 13, the 

spacecraft will image the Mars Pathfinder landing site, using 

refined coordinates obtained during the first attempt.



Winter weather in the northern hemisphere of Mars was a 

significant factor in preventing a view of the landing sites 

during the first series of attempts.  The site of the Viking 

Lander 1 in Chryse Planitia, for instance, was covered with a 

thick cloud layer, which reduced but did not eliminate surface 

visibility.  However, data showed that the spacecraft's pointing 

was off just enough to miss that target.



The spacecraft was able to target the Viking 2 lander site in 

Utopia Planitia, which is farther north and on the other side of 

Mars from Viking 1.  However, this area was heavily overcast with 

clouds and haze, which reduced surface visibility by 70 to 80 

percent and rendered the image unusable.  The spacecraft missed 

the Mars Pathfinder site due to the inaccuracy of landing site 

coordinates.



The project team estimates that Global Surveyor has about a 30 to 

50 percent of imaging each target on a given attempt, due to 

navigation uncertainties and spacecraft performance.



A third and final set of high-resolution imaging of the Viking, 

Pathfinder and Cydonia regions will be attempted on April 21-23.

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



MARS SURVEYOR '98 PROJECT STATUS REPORT

by John McNamee, Mars Surveyor 98 project manager



3 April 1998



Orbiter and lander integration and test activities are proceeding 

on schedule with no significant problems. The orbiter spacecraft 

was moved to the thermal vacuum chamber at Lockheed Martin on 

April 3.  The chamber will be pumped down beginning on April 13 

for approximately 2 weeks of orbiter thermal vacuum testing.  The 

lander spacecraft in full cruise configuration is in the acoustics 

lab at Lockheed and acoustic testing will begin on April 6.



Independent experts conducted a mechanical pre-closeout walkaround 

of the orbiter spacecraft on March 27.  No major items were 

discovered.  Ten minor items were noted as requiring a second 

look.

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



MARS POLAR LANDER PHOTOS

JPL release



3 April 1998



Recent photos of the Mars Polar Lander are now available on the 

Mars Surveyor '98 home page:



http://mars.jpl.nasa.gov/msp98/images/sc9803.html



The Mars Polar Lander is currently being integrated and assembled 

at the Lockheed Martin Astronautics facility in Denver, Colorado.  

Scheduled for launch in January 1999, the spacecraft will land for 

the first time ever in a polar region of Mars in December 1999.  

Additional information on the Mars Surveyor '98 program is 

available here:



http://mars.jpl.nasa.gov/msp98/

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



STARDUST STATUS REPORT

by Ken Atkins, Stardust project manager



3 April 1998



Assembly, Test, and Launch Operations (ATLO) activities:  ATLO 

effort continued wrapping the harness, building/installing the 

main particle "Whipple" shield, installing the CIDA (Cometary and 

Interstellar Dust Analyzer) keep-alive power (defined last week) 

converter and preparing for the solar array switching unit (SASU) 

interface test.  Preparations continued for installing the flight 

solar arrays and for the arrival of many key assemblies for system 

integration later this month.



The thermal vacuum test on the Sample Return Capsule (SRC) was 

completed on both hot and cold cycles.  This is to ensure 

assemblies and wiring have a lot of margin for any expected 

thermal environments on the mission.  Additional testing is 

planned on the deployment mechanisms.



Testing of the Payload & Attitude Control Interface (PACI) board 

with the Cometary & Interstellar Dust Analyzer (CIDA) electronics 

simulator and the star camera and IMU simulations continued 

without problems.



Opportunity and Outreach:  Increased distribution of informational 

bookmarks continued.  The Challenger Centers received a supply for 

their students who will be participating in their "Rendezvous with 

a Comet" educational experience/event.



For more information on the STARDUST mission--the first ever comet 

sample return mission--please visit the STARDUST home page:  

http://stardust.jpl.nasa.gov

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



GALILEO EUROPA MISSION STATUS 

JPL release



9 April 1998



The Galileo spacecraft successfully completed its most recent 

flyby of Jupiter's moon Europa on March 29, and indications are 

there was no change to the gyroscope performance.  Because one of 

the two gyros had been acting up, the closest approach to Europa 

was carried out in cruise mode, with the gyros turned off; the 

spacecraft used only stars to orient itself and point its 

instruments.  However, an attitude-control system performance test 

showed that the gyros did not degrade further during this latest 

pass through Jupiter's intense radiation environment.  Galileo 

project engineers have pinpointed a single computer chip as the 

cause of the anomalous behavior.  This particular chip has 

received more radiation exposure than other similar chips in the 

gyro electronics.



This week, Galileo transmitted to Earth pictures and other science 

information gathered during the latest Europa flyby.  This 

includes one of three observations by the photopolarimeter 

radiometer designed to refine temperature variation maps of 

Europa's surface.  This will help scientists understand surface 

ages and composition and the process that may have formed the 

surface.  In addition, there is information from instruments that 

study magnetic fields and charged particles on the interaction 

between Europa and Jupiter's magnetic and electric field 

environment.  The camera and the near infrared mapping 

spectrometer have returned information on a region of dark lines 

and the Mannann'an crater on Europa.  Data gathered by the 

spectrometer of the south pole of Jupiter's volcanic moon, Io, 

provides the spacecraft's best view of the area until late 1999.



On Friday, April 10, the spacecraft will perform regular 

propulsion system maintenance and perform a turn to keep its radio 

antenna pointed toward Earth.



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.

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End MARSBUGS Vol. 5, No. 10