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Solar System Exploration Today*
A Multifacetect Encleavor
Solar system exploration is ~ grmd humm enterprise that seeks to discover the nature md origins of He
celestial bodies among which we live md to explore whether life exists beyond Earn.
MOTIVATIONS. WHY SOLAR SYSTEM EXPLORATION COMPELS I}S TODAY
To appreeia~ our place in He universe' we must underfed the neighborhood in which we reside. We want
to know how plmets formed' what determined their characteristics, md why ~ least one of them became ~ abode
of life. How haphazard was this formation: Do Parklike planets typically survive' or are they usually swallowed
by Jupi~r-like objects, pushed into their parent parse or flung into the Hostess of interstellar space: Is life ~ rare
phenomenon' or is it the expected outcome of solar system formation: The answers to these profound questions
may be contained in the orbits masses, compositions' gaseous md plasma environments md surface md internal
structures of solar system objects. We may undersold yet more by scrutinizing the plme~ orbiting other stars.
The solar system evolves. Plenary md satellite surfaces record ancient histories of violent impacts' volemie
eruptions, perusal tectonics, md fluid erosion. Planets rings continually Tahoe' active geology is ~ work on He
solid bodies in He outer solar system' md Titans Ionosphere support ongoing organic Nemesis. Marks climax
md internal dummies have echoed dramatically over time. Ear~-erossing asteroids md comes threaten us.
Will we md our plme~ry home survive: Some day people may live on other piked. By investigating these
environments' we em better prepare for our future md perhaps predict He destiny of our species.
Could life have developed on other solar system objects: lament discoveries suggest ~~ the ``h~itable
zoners is not defined simply by distance from ~ Car. Liquid water appears to be seeping out of the frozen cliffs of
Mars md likely lies behead He icy crust of Europa. Life on Earn survives extreme environment. Organic
molecules md chemical-energy sources are ubiquitous beyond our plmet md the ingredients offamiliar terrestrial
life water' carbon' md nib open may have been brought to Earths surface by asteroids md icy comets. Life
itself may have been strewn across the solar sys~m~s archipelago by He impacts of comets md asteroids.
Throughout this report' the word 1' is used ir1 ~ ~rlera1 surly me~irlg compatible with any kind of life. When used to mew
compatible with hums life' the text is qualified as such.
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Representative terms from entire chapter:
research councils
754
HEW FR0~ IN =E 50~R HIM
Exploration of ~e solar system cart reveal how likely we are to find life elsewhere in the univerm arid how it
might be recognized. Just as studies of extreme but rarely visited ~rres~i~ environment have revealed novel
microbic species arid unar~ticipa~d microbial ecosystems, so the deviled exploration of the solar system also
might revolutionize our idea about ~e diversity of life arid the rare of conditions in which it might original
ardor survive.
The scrutiny of ~e solar system provides over examples against which to compare Earth. It also helps us
comprehend fir how our world operates arid how it evolves. The study of the solar system as ~ whole, md of
the individual bodies within it' helps us underbred how ~e moire family of ply formed arid how perry
systems might develop around other stars. It therefore leads us to wonder whether over Earth-like plumb cart
sustain life.
When we discuss life in the context of solar system exploration' it must be clearly understood ~~ success or
failure is not measured Chording to whether or not we actually find life beyond plmet Earn. It is just as import
to know ~~ life does notexist in ~ particular locale' because this may lead to the development of art understanding
of the environmental conditions necessary for lifers existence. This suggests thy life-rela~d studies must be
intimately co~d to studies of ~e origin md evolution of ply environments. Therefore' to assess ~e
habitability of' for example' Mars requires ~ Borough understanding of ~~ plar~et's tectonic' magmatic' hydro-
logie, md climatic evolution, including geoehemiea1 eyeles of biological relevance, Me development of po~tia1
habitats, arid Me processes responsible for Me preservation arid destruction of biomarkers.
To Duly appreciate the apparent uniqueness of Early we must undersold its rocky siblings: Mercury' Venus'
md Mars' as well as the Moon. To uncover clues to the origin md evolution of the solar system md other
plme~ry systems' we mud let about Me gist plme~ md Weir satellites md ring systems. To underfed our
begir~E~ings, we must examine samples from the solar systems oldest md mod primitive bodies: domed md
asteroids.
These issues concerning our place in the cosmos derive from Free of Me mod profound questions ~~ em be
posed about the humm condition: Are we alone: Where do we come from: What is our destiny: These
deceptively simple questions have motivated ~ broad range of humm endeavors, including exploration of scientific
subjects as diverse as cosmology md biology. Nowhere are they more applicable than in solar system exploration.
Plme~ry exploration is also driven in part by our species' seemingly inedible desire for knowledge md Me
application of ~~ knowledge to improve the humm condition. Such aspirations may be realizable as insight into
natural processes md phenomena that affect humm society' potential mitigation of hoards to Each that arrive
from space, md provision of knowledge about space resources that are available for utilization. The unqueneh~le
humm desire to explore, again ostensibly to improve the humm condition, encourages mmy citizens. And who
knows what role is played by Me yearning of humms to know ourselves md to comprehend our place in the
universe: In the words of TV. Eliot:
We shall not cease from exploration
And the end of all our exploring
Will be to arrive where we sorted
And know the place for the first time.
T.S. Eliod' <
SOLAR ~~M E~LORANON TODAY
155
Since time immemorial' ~ driving impulse for science has been to understand the threes the the natural
environment poses to civilization. Some hazards' such as disease' fire, flood, arid earthquake' are obvious arid
have long been ~e subjects of intensive scientific research. Others including climax charge arid ~e Brew posed
by cosmic impacts' have received attention by scientists only in ~e past few decades. The belted recognition of
them throws is ~ consequence of ~e long time scales between destructive events, not art indication thy they are
arty less lathe chart Bow thy have long An known. Indeed' climax chugs Ed cosmic impact are distinguished
by Heir po~ntia1 to devalue civilization as we know it. It therefore behooves us to systematically assess ~e
magnitude of Base Brews.
Climax cart be Eared by modifications in global volcanism' solar output, or ~e influx of in~rplar~ry dust.
Both deterministic arid chaotic celestial mechar~ics introduce variable solar insolation' arid society~s contaminar~
affect the atmospheres response. The interactions among these influences are so complicated thy Hey are nof yet
fully understood. The atmospheres of Venus Ed Mars' for example, evolved such thy Hey differ radically from
Earths atmosphere. To learn ~e reasons for Base differences is ~ Entrap motiv~ionfor ~e SSE Surveys support
of ~ vigorous Mars program arid of in situ investigations of Venus. In the lamer case, temperatures vastly higher
chart those on Earth result from ~ runaway greenhouse effect of ~ magnitude seemingly incommensurate win
Venus,~ slightly smaller orbital radius. Marks thin carbon dioxide Ionosphere represents the other extreme, in
which temperatures are low arid ~ significant fraction of the ahnosphere lies buried as ice within the regolith arid
upper crust. These `~end members', of ~rrestria1 atmospheric evolution nicely bracket the thar~kfully clement
climax prevailing on Earth.
The atmospheric' geological' Ed evolutionary effects of cosmic impact have become apparent only since He
early I98Os, when ~e likely cause of the Cre~eous-Tertiary extinction was first associated with the impact of ~
lO-km as~roid.i Colliding asteroids Ed comets of even much smaller diameter deliver enormous kinetic energy
with possibly deadly consequences raying from local to global. At Congress ~ s direction, He National Aeronautics
Ed Space Administration (NASA) has supported ~ ground-based program to identify 90 percent of the near-Ear~
objects (NEOs) larger than ~ km in diameter by 2008. The task is now Bout half complex, although He best
simulations of He current survey strategies predict ~~ this goal will not be met for mmy deeades.2
Kilome~r-si~d impaetors would be globally devastating' Ed even the much more common smaller projectiles
could wreak unimaginable local havoc in populated areas. The high-altitude explosion of ~ SO-m-diameter body
above Tunguska' Siberia' in ~ 908 felled bees over ~ 2~000-km2 blast zone, Ed would have been sufficient to
flatten ~ large oily. Assessment of the NEO population down to 300-m scales' as pax of ~ ordained inventory of
the small bodies of He solar system, was recognized as ~ high priority for NASA,s Solar System Exploration
program in the most recent astronomy Ed astrophysics deeada1 survey.3 We also need refined physical observa-
tions of these reining objects in order to determine Heir physical properties Ed estimate Heir kinetic energy.
Once humm exploration of the solar system is renewed' Ed especially as soon as lengthy missions begin'
knowledge of the available extr~errestria1 resources will be imperative. Preliminary studies have identified sites
where specific resources may be lowland Ed have suggested the mems to extant these valuable minerals Ed
compounds. Examples include hydrogen `
756
HEW FR0~ IN =E 50~R DIM
competition between the United Scams arid the Soviet Union. Even during thy era the two rivals occasionally
cooperated for examples in ~e exchar~e of lunar samples collected by the Apollo arid Luna programs as well as
in collaborations for the analysis of solar wind interactions win comets. hive recently' in~rn~ion~ collaborative
efforts have grown, leading to various programs thy have significar~tly enhar~ced mission capabilities arid scientific
returns. In~rnationa1 involvement has covered marry different aspects of exploration, from individual scientific
collaborations arid dam exchar~es to joint major undertakings (~.g.~ ~e C~ileo~ Cassini-Huygens~ arid Roset
missions). ~~rn~iona1 coll~or~ions could ~ strengthened by insuring strong participation by non-..
members on science definition Cams for specific projects' as is done for some missions, arid by giving further
consideration to siding groups such as the In~rn~iona1 hIars Exploration Working Group.
Some future endeavors are so vast in mope or so difficult (egg. sample return from Mars) thy no single nation
is prepared to 31100^ ~C resources necessary to accomplish Hem alone. It would be advantageous to ~e Solar
System Exploration program for NASA to encourage arid facilitate such joint ventures so as to allow them to
flourish in the future.
The theme of in~rnationa1 cooperation appears often in Part Two of this report arid the SSE Survey recom-
mend that NASA encourage and continue to pursue cooperative program with other nations
Nevertheless' primarily because of constraints on its scope' this report focuses only on He status arid future of
solar system exploration programs in He United Scams. The SSE Survey adempts to identify where major
incarnations cooperation is advisable but in its discussion of future strategy does nof consider in my depth He
remarkable md exciting plans of other agencies in He intern~ion~ eommunily' nor does it consider the ramifiea-
tions of in~rnationa1 space programs.4>5
MODIFYING THE GOALS OF SOLAR SYSTEM EXPLORATION
Solar system exploration has been pursued in the United Sates for fully four decades. During most of that
time' He seientif~e goals of NASA's Solar System Exploration program have remained quip sublet win their
relative importune gradually evolving over time. The SSE Survey largely reaffirms the statement of scientific
goals made in the Space Studies Lourdes last major survey of He planets seienees,6 but win He following
modifications. First the SSE Survey includes the search for the existence of life' either past or present' beyond
Earth' md second' the Survey seeks to ineorpora~ the development of detailed knowledge of Earths immediate
space environment in order to underfed my potential hoards to our home planet.
The objectives of solar system exploration' ~en, become these:
~ Determine if environment capable of sustaining life exist or have ever existed beyond Earth' what
parameters constrain id occurrence' how life developed in the solar system' whether life exists or may have existed
beyond Earth md in what ways life modifies planets environments;
~ Understand how physical md chemical processes determine He main eharae~risties of solar system bodies
md Heir environments' thereby illuminating the workings of Earn;
Learn how He Surfs retinue of planets md minor bodies originated md evolved;
Explore the terrestrial space environment to disc over what potential h=ards to Earth may exist; md
~ Discover how the simple' basic laws of physics md ehemis~y em lead to He diverse phenomena observed
in complex systems.
In the early years of NASA's Solar System Exploration program, especially during the period surrounding He
Apollo explorations of the Moon' space policy was dominated by political goals: for example, PresidentKermedy~s
decision to place ~ humm on the Moon by He end of He I960s. Then md for mmy years to follow, robotic
spacecraft were dispatched on scientific missions designed to simply dim over He general nature of He solar
system. This era of initial recormaissmee beam in the I960s md encompassed He Mariner missions to Venus'
Mercury, md Mars md the Pioneer md Voyager explorations of planets md s~elli~s in He outer solar system'
md concluded in the I990s with the Galileo, NEAR, md Deep Space ~ explorations of Steroids md domed.
SOLAR ~~M E~LORANON TODAY
157
Today, as ~ result' only ~e myriad newly discovered object within the Kuiper Belt including ~e Pluto-Charon
system arid relend bodies such as Cm~urs arid Trojar~s' remain entirely unexplored by spacecraft.
A new phase of explorationbegar~ win ~e Viking missions to Mars (launched in I975~, ~e Magellar~ mission
to V=us (launched in 1989~' ~e Galileo mission to Jupiter arid its sullies (launched in 1989), arid the Cassini-
Huygens mission now en roux to Saturn arid Titers. The goals of Base missions reflected ~ new focus: more
intensive exploration' including ~e lading md ~e emplacement of atmospheric proms. The science objectives
and from first-order recor~r~aissmce to deviled chemical arid physical explorations of relend objects to
determine Heir origins md to ascertain ~e processes thy shaped their identities, md, for ~e first time' to search
for life beyond Earth.
Today, we find the focus sharpening further' following the 1996 armouncement thy ~ meteoric' ALH84~'
which likely originated on Mars' showed evidence' albeit of ~ highly controversial nature' of possible past life
activity on thy plmet.7 The claims concerning ALH84~' though questioned from ~e outset arid now generally
di~redi~d, triggered ~ series of subsequent scientific, political' arid programmatic initiatives thy have had ~ very
positive impact on solar system exploration. Prime among the benefits was the so called Origins enhar~eement to
NASA's budget for FY 1998. Since ~en, He Mars component of NASA,s Solar System Exploration program has
enjoyed increased support md has developed according to strategies sometimes termed ``Seek' in situ' md sample,'
arid ``Follow He wa~r.~' These strategies are ultimately aimed ~ determining He conditions of Mars arid whether
life ever arose on ~~ plar~et. The program of geological' geoehemieal, md geophysical explorations now under
way is preparatory to the future return of matrix samples from Mars to terres~ia1 laboratories md is directed in
part to resolve these questions.
Other observations have initiated this redirection in mission focus. For example' magnetie-f~eld measure-
men~ md images from He Galileo orbiter in He late 1990s strongly suggest ~~ ~ 100-km-deep global ocem of
water, ~ possible abode of life' may currently reside below He icy crust of the Jovian satellite Europa. Similar
magnetic characteristics also indie ate possible subsurface ocems within C~ymede md C~listo. These measure-
men~ have prompted NASA to study intensively ~ orbital mission to begin deviled probing of Europe putative
ocem. Simultaneously' in He crucial area of Earth-based studies, NASA instituted the well-funded Astrobiology
program in He late 1990s. lleseareh funded Trough NASA,s preexisting Exobiology program resulted in He
discovery of He ~ree-domain, phylogenetie tree of life md revealed He evolutionary signifiemee of organisms
from environments previously thought to be incompatible win carbon-based life (e.g., hot springs md deep-sea
vents).8 That such organisms extremophiles occur on Earn wherever liquid water exists has expanded our
notion of what constitutes ~ habitable world. This md over related discoveries prompted NASAL informed
eommi~nent to the search for life elsewhere in the solar system as ~ significant aspect of id exploration stringy.
Astrobiology as does its intellectual precursor' exobiology has ~ reciprocal relationship win solar system
exploration. It provides guidance for mission design md ~ framework for interpreting new discoveries. Originally
concerned with ea~loging observations of phenomena ~~ might be characteristic of life found in regions beyond
Earthts atmospheres astrobiologist now study all processes thy are associated with the formation' population'
md extinction of habitable worlds.~°~i ~ The intellectual goals of this scientific discipline embrace Tree questions:
How does life begin md develop: Does life exist elsewhere in the universe: What is the future of life on Earn md
beyond:
Astrobiology~s multidisciplinary Trust provides ~ integrating theme, bringing together ~ subs~tia1 fraction
of the issues in solar system exploration under the common Tread of understanding plme~ry habitability. [lather
than merely addressing the distribution of life in the universe' astrobiologists are concerned win clarifying He
d~amiea1 past of He solar system that led to terrestrial plme~ md their satellites' the interplme~ry hmsport
meehmisms responsible for cross-solar-system redistribution' the history of volatile md organdies, the processes
(exospheric md surficial) thy affect He evolution of vol~iles md the formation of habitable planets' prebiotie
chemist md the emergence of life, the influence of impaetors on the survival of living systems' md all processes
that lead to loss of He habitability of solar system objects. Astrobiology has both empirical md experimental
dimensions. It seeks ~ historical accounting of the evolutionary processes that guided solar system formation md
the emergence of life on Earth. At the same time, astrobiology aspires to underbody Trough multidisciplinary
experimentation, the theoretical basis of how md why these processes occur.
758
HEW FR0~ IN =E 50~R DIM
Astrobiology as ~ Demo provides ~ scientific organizational structure ~~ integrals ~ wide subset of solar
system issues arid questions thy spars the origins' evolution, arid extinction of life. This theme allows nonexper~
to grasp the commotions between different component disciplines within plenary science arid to do so in ~ way
thy most people will appreciate as addressing core themes in hum art thought. Astrobiology arid id connections to
space science tared solar system exploration in particular) are the primary metros by which NASA tries to imple-
ment one of its prime objectives understar~ding lifers origins arid its distribution in the univerm.
Astrobiology also has some priorities ~~ are intimately cor~r~d to arid rely on perry exploration.
Scientific objectives mentioned lair in this survey of solar system exploration thy directly address key questions
in astrobiology include the following:
~rmination of the composition, abundance, md distribution of orgar~ic materials in ~e solar system;
~ Exploration of both the politic occurs where life might emerge arid ~e radiation environment ~ ~e
surface arid near-surface regions of Europa arid the over Galilear~ sa~lli~s;
~ Detailed de~rmin~ion of the elemental' chemical, isotopic, md miner~ogica1 composition of the surfaces
arid upper Grubs of planets arid sa~lli~s (including Mars' outer solar system sullies' arid icy objected;
~ Investigation of the nature of atmospheric evolution arid geochemistry on Venus arid Mars relative to thy
on Earn in order to understand the po~tia1 for perry evolution into habitable versus shrill worlds;
~ Description of ~e detailed history of impactors arid their po~ntia1 influence on ~e evolution of ~rres~ia1
biospheres; md
~ Further exploration of Mars, including ~ deviled search for subsurface liquid wear md possible ground-
ice inventories, full determination of surface mineralogy' md assessment of possible spatial md ~mpora1 juxtapo-
sition of liquid wear md sources of energy that could support life.
NASA's Astrobiology program has become ~ fundamental part of Be solar system exploration strategy. The
SSE Survey encourage NASA to continue the integration of astrobiology Friend oh~ectives with thme of
other space-wience disciplines+ Astrohiologi~l expertise should he called upon when identifying optimal
minion strategies and design requirements for flight-yualified instrument that will address key questions
in astrobiology and planetary science+
The goals for solar system exploration advocated in this report are sufficiently comprehensive to be resilient
to the kind of minor readjustments in focus just described. ~ ~ real sense' todays objectives' as rephrased ~ He
begir~E~ing of this section' define what the SSE Survey believes solar system exploration is md should be. How-
ever, as discoveries are made' eh~ges in emphasis among these Crush are inevitable. Today, solar system
exploration focuses predominantly on questions of habitability md He possible exis~nee of extraterrestrial life.
The Presidentts 2003 budget for example' proposes the New Frontiers program with precisely this overarching
goal. The SSE Survey interprets this objective broadly' since my plan to address the possible existence of
extraterrestrial life presupposes ~ extensive investigation of plme~ry evolution md of He planetary conditions
that are conducive to the development of living organisms. In this regard, it should be noted that some of He
primary goals of astrobiology em be met most efficiently Trough understanding p~ieular plmet~ bodies md
the way that they fit into the broad context of the solar system as ~ whole.
It is difficult to judge with eonf~denee He degree to which He goals of the in~rnationa1 eommuni~ have
Blared to parallel those of He United Scams. Certainly the Soviet program shared the same early emphasis on
lunar exploration md sample return, but it was originally more clearly focused on robotic investigations md
techniques. Soviet recor~E~aissmee missions to Venus md Mars quickly followed' win significant successes in
robotic ladings on the hellish surface of Venus.
1lecor~E~aissmee of He solar system by other nations experienced grew success In me incus' wan me first
explorations of Comet Halley~s nucleus by the Vega' Giotto, Suisei' md Sakigake spaceport. Together' these
missions filled in ~ almost-empty paradigm with unexpee~d details concerning the nature of biometry aetivily
md He composition of biometry solids. Today He incarnations community is mounting major geophysical md
geoehemiea1 explorations of the Moon, Mars, comets' md asteroids win the Selene' Nozomi' Mars Express'
Beagle 2, Smart I' loosen' md MUSES-C missions.
. ,~ ~ ~ ~~ · . ~ . ~ ~
SOLAR ~~M E~LORANON TODAY
RECENT A~IIEVEMENTS IN SOLAR SYSTEM EXPLORATION AND RELATED FIELDS
159
Our perceptions of our perry neighborhood have Den overturned since the spwe age dawned. Don of
light in the night sky have been har~sformed into exquisite worlds displaying bizarre phenomena softly hued
vortices swirling past Jupi~r~s Red Spot enormous Rayons arid outflow washes crisscrossing hIars, or austerely
beautiful rings encircling each of ~e girt plar~ets.
The remarkable diversity arid activity of ~e solar system were fondly unexpected by perry scimlis~ arid
were forecast by just ~ few others' but mostly as science fiction. To illustrate the vi~lity of the discipline, it may
be instructive to mention just ~ few of ~e findings since the publication of the last solar system survey less ~m
decade ago.~3 Most of ~~e new understar~dings lead to additional questions.
To identify the most import=" discoveries of the past decade, ~e SSE Surveys Sharing Group relied upon
community input to in parcels (~e Part One), along win independent surveys of the scientific community arid ~e
public (see Appendixes ~ arid D). Box 6.1 lists ~e most significar~t additions to our underfunding of the solar
system' while Box 6.2 outlines ~ half down of the most vexing md mysterious issues facing plenary scientists
today.
A plethora of exhasolar diary Blarney, whose orbital characteristics have startled theoreticians' have been
discovered elsewhere in our galaxy. Indeed, perhaps ~ percent of main sequence stars have massive eomp~ions'
but He ubiquity of terrestrial-like plar~e~ remains urn own. Simultaneously, dust disks have been found to
commonly enshroud most young stars' md even some aged ones. These observations suggest that He formation
of planets is not unusual.
llesearehers now wish to use ground-based telescopes md future spaceport, such as Kepler md the Space
In~rferome~ Mission (SIhi)' to observe ~ s~tistiea1 sample of ex~asolar planets in order to better undersold He
origin md evolution of planets systems. Such studies will eventually be extended to He search for Ear~-like
plme~ md' ultimately' will eharae~rize their ahnospheres md Heir habitability with advanced orbital observ~o-
ries such as the proposed Terrestrial Planet Finder (TPF) mission. Our understanding will be improved if we use
the properties of our own gas gibe to calibrate the processes exhibited in other plme~ry systems md to obtain
clues to the primordial composition of the solar system.
Since the first Kuiper Belt object was detected in 1992, hundreds more have been sighted, disclosing ~ large
extension to the solar system beyond Neptune. Similar structures are inferred to explain He oldest of the extrasolar
disks. We are in He midst of compiling the first catalog of this territory thy circumscribes the outer solar system
so as to unravel id morphology md makeup md to allow ~ understanding of id relationship to He formation of
the solar system.
Ado
HEW FR0~ IN =E 50~R HIM
The discovery of possible subsurface ocems on several Calilem sa~lli~s has led to the recognition of ~
possible but unexpected abode for life beyond Earn. The current goals are to identify md Carmine the extent of
my such subsurface ocem. Simultaneously we must rethink our imps of habitable zones.
Evidence continues to Cumuli indicting ~~ water flowed on or near the martim surface in geologically
reeenttimes. This, together with indications of subsurface reservoirs of fee md geological aetivily' suggests that
the lied Planet might have been hospitable to life in its past. We now should continue to document He nature of
my put habitable climate md to characterize Be extent of subsurface wear md fee to see how closely Hey
approach the surface. In situ investigations for water md evidence of pad or present life should also be eondue~d.
Aeeeptmee of the possibility of extraterrestrial life has progressed markedly during the past decade. Illush~-
ing this are claims made for extinct life forms in the ancient martim meteoric ALH84~. While these claims
have been sharply disputed' the debate has been on scientific terms md has concerned the validity of He evidence.
This new perception in pad also results from He concurrent discovery of terrestrial ex~emophiles. This discovery
encourages ~ continuing search for md examination of other martim meteorites for biological evidence. Also'
samples of known provenance should be returned to Earn for their mineralogies md isotopic characterization md
ultimately to verify my in situ hiologiea1 evidence.
As ~ find example of He advances made in the last decade, scientist in He I99Os realized the crucial role of
impacts in aItering lifers paw once they identified the Chixulub eraser in He Yuea~ as responsible for He
Cret~eeous-Tertiary (K-T) extinctions on Earn. In the same period' the pummeling of Jupiter with He remand
of Comet Shoemaker-Levy ~ reminded us all of He ubiquitous md continuing role of collisions in shaping
plme~ry bodies. As ~ result of these findings' we now recognize that we mud survey He skies for threading
SOLAR ~~M E~LORANON TODAY
NEOs md maintain ~ wash for po~ntia1 impactors.
To make Base identifications useful' we also need to
determine relevar~t physical arid compositional properties of po~ntia1 impactors, including combs.
THE RELATIONSHIP OF SOLAR SYSTEM EXPLORATION
TO SCIENCE AND ENGINEERING DISCIPLINES
The success of ~ solar system exploration mission relies crucially on the well-being of ~ wide rage of
scientific investigations arid effective engineering To ~ of value' missions nof only must reach their Urged
quickly arid win adequate power arid stability, but also must produce signif`~ar~t scientific dam thy address ~e
scientific goals fond previously. Scientific investigations are usually drawn from various established disciplines'
including perry science' geophysics' geology' atmospheric physics' cosmochemistry, fluid mechanics'
me~oritics, space plasma physics, astrobiology' arid aeronomy to name but ~ few.
This point is made to emphasize ~e wide array of scientific disciplines thy are informed by solar system
exploration. The interaction anthem ~e disciplines arid missions flows both ways solar system exploration
missions rely on ~ healthy scientific community for support arid direction' md the value of ~e missions is
dramatically Ahead by research thy capitalizes on resumed dam. The nations solar system exploration
en~rprim is driven by ~e high-leve1 public goals outlined above' but it is not possible without strong support for
the scientific arid engineering backbone of ~e program. This support is currently lacking in several areas' which
are detailed lair in this report.
THE SOLAR SYSTEM EXPLORATION PllOGlIAM AT NASA.
INTERREL ATIONS HIPS
Relationship with Other Science Program
Solar system exploration is currently overseen by two components of NASA's Office of Space Science (OSS):
the hears Exploration Program (hIEP) office md the Solar System Exploration Division. This dual responsibility
is recent md was apparently imposed to ensure that the exploration of Mars could progress ~ as rapid ~ pace as
possible without being fettered by my problems ~~ might arise in the more general program. The Solar System
Exploration program is strongly coupled seientif~eally to over separately mmaged programs in NASA. Within
the OSS, He strongest scientific md programmatic bonds are to the Sun-Earth Erections Division md He
Astronomy md Physics Division.
The Sun-Earth Cormeetions (SEC) Division sponsors research in solar md space physics with particular
emphasis, as id name implies, on He Suns effects on the terres~ia1 space environment. However' space physics
research is not only concerned with solar-terreshia1 relations but also encompasses study of the space environments
of over solar system bodies. SEC strategic plying documents Bus typically include missions to inve~iga~
plme~ry magnetospheres' ionospheres' md upper a~nospheres.~4 A major thrust in He Sun-Ear~ Cormeetions
Division is He Living With ~ Star program its purpose is to understand these Sun-Earth eormeetions for very
practical applications. This program overlaps with planets wienee by aiming to help unravel how plme~
interact win solar insolation md the heliosphere' in order to understand the past md future climate md the gaseous
md plasma environments of one very well studied plmet.
The astronomy md astrophysics flightprogram eondue~d by the Astronomy md Physics Division is mmaged
as two separate thematic groups, Structure md Evolution of the Universe md Astronomical Search for Origins.
lloughly speaking, the forgery activities are molly devoted to high-energy astrophysics' whereas He lantern
activities are devoted to less-energetic phenomena that are more relevant to the ingress of solar system explora-
tion' but not exclusively so. Planetary science has benefited enormously from Astronomical Search for Origins
missions such as He Hubble Space Telescope (HST), md it expects more discoveries from the Space Infrared
Telescope Facility (SIFTS), the Sh~ospherie Observatory for Infrared Astronomy (SOFIA), md other future
space observatories (see below). Future Origins missions such as SIM md TPF are essential to extending
plme~ry exploration beyond our own solar system, searching for other planets systems' md then mounting
HEW FR0~ IN =E 50~R HIM
spectroscopic investigations of extrasolar ply for evidence of biospheres. We me here examples of the among
in~rrel~ionship between studies relying to solar system exploration arid astronomical origins. One provi~s
very detailed look ~ one example of perry formation md evolution, while the other provi~s marry examples
of ~ wide variety of systems win different structures arid ~ different sages of evolution.
Plar~ry science also has strong scientific links to NASAL Office of Earth Science (OES). Earn is the most
innately studied Claret from space. Hence ~e science md observational techniques developed in OES are vital
for the continuing development of perry science arid observations. The major Crust in OES is the Global
Charge program, from which plenary science will gain ~ understanding of Earth as ~ ~rreshia1 planet among
the four inner ply md will obtain dam esmntia1 to understanding the origin arid evolution of ~ ~rres~ia1
perry biosphere.
Studies of the Ionosphere arid plasma environment of solar system bodies have men ~ in~gra1 part of ~e
general solar system exploration effort since the launch of Mariner 2 in 1962 md are traditionally supported by
NASA's Solar System Exploration program. Historically, some small but very imports funding has also come
from NASAL space physics activities arid the Nations Science Foundations astronomy arid atmospheric science
programs. This orgar~iz~iona1 arrar~gement made sense in He past arid will continue to do so in He future'
especially for in situ studies because spaceport traveling to various solar system bodies earl arid should carry ~
wide Urge of instrumentation. Examples of such successful undertakings are He Voyagers md He Galileo arid
Cassini orbits missions, as well as smaller ones such as Pioneer Venus. Comparative aeronomy md magneto-
sphere studies allow the knowledge of basic physical processes Squired through He study of the geo space
environment to be applied to over solar system objects md afford ~ critically impor~t opportunity to test our
understanding of these processes by observing how Hey operate in other settings. Moreover' nof only are there
important eormeetions between space physics md planets wienee with regard to seientif~e themes relevant to
both disciplines' but the ins~umen~tion used in terreshi~ space physics research md that used in solar system
exploration also frequently have ~ common heritage.
Given the erosseuding interests among solar system exploration md terrestrial aeronomy md space physics
studies' it is not surprising that He Space Studies Lourdes concurrent Solar md Space Physics Survey Committee
also addresses some aspects of solar system exploration.5 However' the nature md relative timing of these two
somewhat parallel N1~C studies did not permit as much direct eoordin~ion as would have been wished. Therefore'
the recommendations assoeia~d with solar system exploration from these studies may advoea~ some different
exploration strategies md priorities. These differences em md should be easy to resolve within He OSS. The
excellent pasteooper~ion between He different components of He OSS md among He scientific communities has
encouraged md led to major advances in He field (em., the putative discovery of ~ ocem ~ Europa by magnetie-
field observations) as well as exploration efficiencies. The SSE Survey strongly encourages He eontinu~ion of
this eooper~ive exploration strategy.
Relationship with the Human Exploration Program
The Solar System Exploration program currently has no strong scientific or programmatic ties to the humm
spaceflight activities eondue~d by NASA's Office of Space Flight (OSF), although strong interactions occurred
during He Apollo program. The planetary program does, however' rely on He OSF for the procurement of
launch services. The major thrust in the OSF is the construction of He In~rn~iona1 Space Station (ISS)' win
which no obvious eor~E~e~ion with planets exploration exists over ~m He po~tia1 of the ISS to serve as
future ~mspor~tion node to He plme~ for bow humms md robots.
Eventually Here must be ~ strong coupling between robotic md humm space exploration. Scientific explora-
tion of the solar system md the scientific utilization of the space environment provide He impetus for humm
6~ its morrow program category' for example' the Solar Id Spam Physics Survey Committee assigned high priority to ~ Jupiter Polar
hlissiorl' ~ Medicaid spay physics mission to gum high-l~itu~ eleckod~amic coupling betters Jupiter >s ionosphere Id magnetosphere.
SOLAR ~~M E~LORANON TODAY
exploration beyond Earth orbit' arid they are ~ prerequisite for sending humerus to other worlds. Robotic
missions, for example' will collect the dam necessary for sending astronauts to Mars arid back safely.~7 These
precursor experiments arid measurements would provide information on target selection, surface physics arid
chemistry' ~e Brew thy high~nergy particles pose during travel, md so on. ~ ~e long run' hum art exploration
of our celestial neighborhood is ~ driving force in its own right but it will also furnish opportunities for significar~t
science accomplishments.
The SSE Survey is not convinced ~~ humeri exploration beyond Earth orbit will raise major issues for ~e
perry science community during ~e coming decade. Nevertheless, it would ~ ~ mistake for scientists to
dismiss out-of-har~d Nose individuals aspiring to return to ~e Moon, to walk on Mars' or to exploit ~e resources
of near-Ear~ objects. This is Lue if for no other reason thm to avoid future cornice over limited resources. A
prime lesson from recent humeri exploration activities is thy prior plarming by scimlis~ might preclude
Shown wedding,' sometime in ~e future.
ISSUES llEGAllDING THE INFRASTllUCTUllE
OF THE SOLAR SYSTEM EXPLORATION PllOGlIAM
It is far beyond ~e scope of this survey to give art exhau dice ar~alysis of the current performers of the entire
scientific arid programmatic ir~frashucture of U.S. solar system exploration activities. However' the SSE Survey
bee ame aware of several eontroversi~ issues concerning He way this infrastructure currently operates. It is hoped
that raising these issues will help He audience for this report recognize He `
OCR for page 164
~4
HEW FR0~ IN =E 50~R HIM
R&A programs are not currently arid in the opinion of the SSE Survey should not be tied to specific
mission goals. Thus, individual research projects do not correspond to particular missions. Nevertheless' as ~e
breadth arid dupe of ~e space exploration missions increase' the R&A programs should expand arid be redirected
correspondingly. Therefore' in ~e broadest sense, R&A programs must be responsive to the current mission
opportunities even if they are not rigidly coupled to them.
Previous NRC studies have shown ~~, Mar ~ serious decline in the early to mid-~9Os,~ ~e overall funding
for R&A programs in NASA's Office of Space Science has, in recent years' climbed to approximately 20 percent
of ~e overall flight-mission budget. Figures supplied by NASAL Solar System Exploration program show thy
the corresponding value for perry activities is closer to 25 percent arid is projected to Day ~ about this 1~1 for
the next several years. The SSE Survey believes thy this is art appropriate allocation of resources.
Creation of Intellectual Apical
Finally, to maintain arid enhance He scientific productivity of the entire solar system exploration en~rprim
arid to ensure He creation of new in~llectua1 capital of the higher quality in the field, the SSE Survey recom-
men~ the initiation of n program of Planetary Fellows, that is, n p~tdo~ornl program analogous to the
Huhhle and Chnnilrn fellowships' which have done so much to nurture the next generation of astronomers
nnil astrophysicist. The purpose of this program would be to allow the brightest young investigators He
opportunity to develop independent research programs during Heir most crevice years. These would be presti-
gious' multiyear fellowships' based solely on highly competitive research proposals md Enable ~ my U.~.
institution.
TELESCOPE FACILITIES
AN ESSiENl7IAL ELEMENT OF AN INTEGRATED SiOLAll SYSTEM STRATEGY
Ground-hn~ Telescopes
Two major scientific findings of He pad decade' according to ~ raking by planets seienti~s (see Box 6.1
md Appendix C), were made using ground-based telescopes. The discoveries of extrasolar plme~ md of He
Kuiper Belt have had ~ undeniable impact on our perception of our surrounding solar system md Bus on He
optimal strategies for future spaceport missions.
Except for the major plmets out to md including Saturn, all of the bodies of He solar system' including all
those visited by spacecraft were discovered by ground-based telescopes. Spacecraft provide invaluable in situ
dam on objects ~~ were firm identified from the ground. Utilization of He enormous discovery po~ntia1 of
ground-based telescopes is ~ essential part of ~ integrated stringy for solar system exploration.
Telescopes are vital in sever al ways. Fired they provide He Urged to which flight missions em lair be
directed. A prime example is thy of He Kuiper BelL which emerged in the I990s as ~ vast unexplored And
previously only postulated) <~third domain', of He solar system beyond He realms of He terrestrial md Mint
plme~. Even our yet-preliminary understanding of the dummies of the objects beyond Neptune has led to wide
aceep~ee of the outward migration of proto-Neptune ~ He solar systems dawn.
Another example of ~ <
SOLAR ~~M E~LORANON TODAY
~5
A second way in which ground-based telescopes are importers is the Hey provide ongoing support for
spacecraft missions, both before arid Mar ~e mission. As art example' NASA's Infrared Telescope Facility,~
(IRTF,s) thermal imaging of ~e Galileo promos end sin showed the the probe descended through art Typical
"hot spot,, in Jupi~r~s cloud tops. This knowledge has proven crucial to ~e scientific in~rpret~ion of ~e
compositional dam returned by the probe arid in particular in explaining why ~e measured wear abundances were
unexpectedly low. Similarly' the success of ~e S~rdust md pep Impact missions crucially depends upon
ongoing ground-based charw~riz~ion of Weir target domed. The mission-funded studies of ~e Deep Impact
target, for example, have grimly reduced ~e volume of parameter space thy mud be considered by the mission
designers. Moreover, events associated with the impact into the target will be observed by ~lemopes around ~e
world, complementing observations made by ~e spacecraft~s instrument. Another good example of mission
support concerns ground-based studies of the physical charw~ristics of ~e asteroids Gaspra arid Ida prior to ~e
encounters of the Galileo spacecraft.
In ~ much broader sense, Ear~-based observations provide the context for mission result. Earth-based
studies alone have allowed us to develop taxonomic systems for asteroids md comets. It is through Best
cl~sific~ion schemes thy it is possible, for example, to expired ~e interpretation of result from the Near-Ear~
Asteroid Rendezvous (NEAR) missioner studies of Eros to other similar asteroids.
Ground-based plar~e~ry radar facilities ~ Areeibo' Puerto Rico, arid Coldstone' California, are used for
detailed, physical eharae~riz~ion of marry different bodies in the solar system. Much ofthe initial recormaissar~ee
of Venues surface was eondue~d win the Areeibo telescope' providing valuable input to md context for sub-
sequent radar studies undertaken by the Moselle mission. The same facility has also identified highly reflective
area on Mercury thought to be due to fee located in permanently shadowed craters in Me plmet~s polar regions.
Similarly, He Coldstone facility he been used to study the bulk surface properties of the icy Calilem Bellies.
Both facilities have been employed to `~Doppler-image', several near-Ear~ asteroids, providing information on
their shape, surface roughness' composition' md spin stalk in addition to dramatically improving measurements of
their orbit.
Although impor~t to solar system exploration, planets radar studies ~ both Areeibo md Coldstone are
highly leveraged activities. Roughly 90 percent of the Areeibo budget is provided by NSF to support general radio
astronomy studies. Similarly, the bulk of He Coldstone funding arises from id role as ~ eommunie~ions hub in
NASA's Deep Space Network (DSN).
NASA continues to play ~ major role in supporting the use of Earth-based optical telescopes for planetary
studies. It funds the complex operations of He I1lTF, ~ 3-m-diameter telescope lowland on Hawaiits Mauna Kea.
In return for amess to 50 percent of He observing time for non-solar-system observations, He NSF supports He
development of IllTF,s ins~umen~tion. This telescope has provided vital dam in support of flight missions (as
described above) md will continue to do so. NASA currently purchases one-sixth of He observing time on He
privately operand Keek 10-m telescopes. This time was purchased to test in~rferome~ie techniques in support of
future spaceflight missions such as SIM md TPF. However' the fraction of He NASA time available for general
solar system observations is rapidly shrinking as He Keek interferometers come online.
The SSiE Survey recn~nen~ that NASA continue to support ground-h=ed oh~ervatories for planetary
science, including the planetary rear ~pahility at the Areciho Oh~ervatory in Puerto Ciao and at the Deep
Space Network's Goldstone facility in Californian the Infrared Telescope Facility on Maunn Kea in Hawaii,
and shares of cutting-edge telescopes such ~ the Keek telescopes on Mung Kea' ~ long ~ they continue to
he critical to missions andlor wientiB'~lly productive+
Interestingly' NASA has no systematic survey eapabilily to discover the population distribution of He solar
system bodies. To do this' NASA relies on research crams to individual observers who must gain access to their
own facilities. The large NEOs are being efficiently discovered using small telescopes for which NASA provides
instrumentation funding, but all the other solar system populations for example, comer' Centaurs, satellites of
the outer planets, md Kuiper Belt objects are being characterized almost entirely using non-NASA facilities.
This is ~ major deficiency' since ~ large-aperture survey telescope will be essential to support the flight-mission
strategy (for example, by selecting md characterizing key targets of the mission) developed in Chapter 8' where
the SSE Survey makes ~ strong related recommendation.
HEW FR0~ IN =E 50~R HIM
Space-~l Telescopes
Marty significar~t discoveries in perry science have come from Earth-orbiting telescopes operating
variety of different wavelengths. Them discoveries include ~e following:
The unexpected detection of strong x-ray emissions from comer;
Studies of joviar~ atmospheric chemistry based on HST observations of ~e impact of Shoemaker-Levy
into Junior; arid
1 ~
The discovery of ~ serfs strong wear emission ~~ is best in~rpre~d as the evaporation of icy bodies in
the outer plenary system of the star.
The ar~ticipa~d launch of SIRTF arid the flight of SOFIA will provide additional superb tools for perry
science, particularly in determining absolute sins md ~e surface reflectivity of numerous objects in the Kuiper
Belt. The Long Duration Exposure Facility (LDEF) made major contributions to our understanding about ~e
nature arid provenance of in~rplm~ary dust.
Win the exception of the recently relend Kepler mission in ~e Discovery program, these orbiting ~lemopes
have been built arid operand under the auspices of NASA's nonplar~ programs. Indeed, because of ~e
commonality of the tools used by ply - astronomers arid Heir colleagues inbreed in stellar, galactic' arid
extragalactic phenomena, virtually every major ~tronomica1 mission thy has flown has made some significant
contribution to solar system exploration. The clom coincidence between the ins~umen~tion used by planetary
md other astronomers makes it urmeeessary for the SSE Survey to recommend ~ major Earth-orbiting telescope
devoted exclusively to solar system studies. The Survey prefers to rely on He Discovery md' where appropriate'
the Explorer lines to general appropriate e~dida~s. It is noted' however' that using Earth-orhiting facilities
for planetary oh~ervations impm~ special Unstrung notably the need to tram fling target and the
SSE Survey endorses the incorporation of this technically difficult hut essential ~pahility on ~11 relevant
tronomi~l teletypes.
DATA A1IClIIVING
The Planets Da~ System (PBS) was developed to provide the archiving function through working seien-
tists; in astrophysics' dam archiving is provided by the operating entities for He Hubble Space Telescope md He
other Grew Observatories. The budgets for early Discovery missions (e.g., Lunar Prospector) md teehnology-
demonshation acidities (e.~., the Department of Defense is Clementine md NASA's Deep Space I) made no
provision for archive products. As ~ result dam from these missions have been very little analyzed. The recent
success of He NEAR mission md its return of ~ huge volume of dam ~ order of magnitude more thm when He
mission was plied have highlighted the importance of archiving as ~ separate activity within solar system
exploration. These events have also illustrated mmy of the pitfalls in establishing ~ archive from ~ highly
productive mission that was budgeted in He Discovery range. The risk exists that He scientific return from solar
system exploration missions will be smaller thm ideal as small' prineipal-inve~igator-led missions proliferate.
Although it is too early to judge' it appears ~~ the Mars program he already begun to ensure thy archiving will
be well handled.
At present, the PBS appears to have insufficient resources for the job it has been given. Moreover' only rarely
is the PDS involved ~ ~ scientific parker ~ ~ missions outset. By eonbast' ~ new instrument for HST is
developed win eonsider~ion for He pipeline processing md archiving from the outset. The PBS faces two
distinct challenges in the immediate future He diversity md number of missions on the one had md the volume
of dam on the over. The interaction with mmy different missions is currently severely stressing He capability of
the PBS. On the technological front He Mars llecormaissmee Orbiter alone is projected to return ~ least
300 terab~es of dark ~ volume exceeding that of all He Grew Observatories combined md presenting ~ major
challenge to He PBS.
SOLAR ~~M E~LORANON TODAY
~7
The increasing attention paid to archiving plans in the recent rounds of Discovery selections he been ~ pep
forward, as has the recent support by ~e Mars program' although ~e overall situation remains unsatisfactory. The
SSE Survey noose for example' ~~ all Discovery proposals are required to budget ~ to 2 percent of their total cost
for education md public outreach (ElPO)' ~ valuable activity thy is also highly leveraged with ex~rna1 resources.
The total amount of money spent on preparing archival produce by arty mission is small compared to this, win ~e
only leveraging Ding in the PUS budget, except in the special case of non-NASA missions for which Bare is large
leveraging Trough ~e outside agency. This is ~e funding thy is intended to provide ~e complex archival
product ready for use by ~e research community. The PBS is funded, ~ present just to maintain suitable
standards, to advim the missions, md to distribute ~e archival products' nof to prepare ~em. The SSE Survey
bows thy in marry cases the experience resident in the PBS could lead to more efficient prepar~ion of archives if
the PBS scientists were involved ~ the earliest stages. Furthermore, subs~tia1 community demand exists for
access to the large databases of E~h-based dam produced through NASA's R&A programs—dam ~~ are in
general nof archived with the PBS for lack of resources. Enhar~emen~ to either the POS or mission budged
would enable dam archiving
The SSE Survey strongly encourages exploration of ways to accomplish the following+
Improve the early involvement of the PUS with missions,
Inere~e the PUS budget anal streamline id pr~ures, while not lowering standards or eliminating
peer reviews' in order to deal with the Ott' perhaps considering the function to he funded at n fixed
fraction' such ~ 1 percent of the minion development and operations budget in addition to n small hue
budget' to ensure that the PDS On cope with varying amounts of Forgiving' and
~ Ensum that missions ~ well ~ 11&A projects producing large Ton hem have ndeqante funding for
~ + +
proper nrenl~ng+
DATA-ANALYSIS PllOGlIAMS
A crucial task in ceding scientific value from solar system exploration missions is to properly org~ize md
adequately fund strong d~-~alysis programs ~APs). In order to maintain momentum' DAPs for the eommunily
should be ready to support investigators immediately upon He delivery of ready-to-use dam to Be PDS. This
would allow continuity for investigators on short-lifetime missions that have reached their end, md it would Flow
outsiders sufficient monies to promptly attack scientific questions based on the dam. ~ addition to providing
adequate funding' several over procedural steps mud occur.
Preliminary versions of the ultimate archival materials must be delivered regularly throughout the mission to
avoid delays in the availability of final products ~ Be missions end. This requires the involvement of the PBS ~
~ scientific parker very early in Be mission. It also requires describing' in some devils the tenant of Be archive
sufficiently before the DAP proposals are due, so that proposers em make sensible proposals before Be dam
themselves become public. It also mandates ~~ investigators be able to propose across missions when scientific
questions clearly transcend individual missions. NASA's stand intent to merge albeit ~ number of years in Be
future the DAPs for individual Discovery program missions into ~ single DAP for the Discovery program
appears to be ~ step in Be right direction. This could allow ~ researcher' for example' to coherently analyze dam
from the several missions to comets, md, similarly, ~ Mars-da~ analysis program could allow ~ researcher to
eompar~ively interpret dam from sever al missions of the Mars program. The SSE Survey urges that these d~-
analysis programs be kept sufficiently flexible so that it is structurally easy to add ~ component for analyzing dam
from other sources' such as from technology missions Deep Space ~ dam from comet I9P~orrelly (Figure 6.l
represents ~ current example or from foreign missions archiving win Be PDS (Mars Express, for example).
NASA's Grew Observatories, most no~bly Trough Be Space Telescope Science Institute (STSeI), but also
other Grew Observatories' have conclusively demonstrated the grew value of ~ uniform' readily accessible archive
coupled with support for the analysis of the dam by the original investigators as well as by others who use Be
archived dam for research. Each scientific user of ~ Grew Observatory is funded to analyze the dam obtained in his
or her program' md Be mission itself maintains ~ long-~rm archive. Because the Grew Observatories are
Ads
HEW FR0~ IN =E SOLAR MOM
FIGURE b. ~ A closeup image of ~e nucleus of Ant 19P~orrelly obeying by ~e D=p Spat ~ spacecraft. Courts of
NASA/JPL.
archiving large volumes of d~a from only ~ few instruments operated over ~ very long time' the archiving process
becomes highly automated, md dam appear in the archive Epically within days of being obtained Ad long before
they become publicly available. The dam in He archive become public after ~ short period' varying from one
observatory to mother' but usually in no more than ~ year Ad sometimes immediately. Come da~ are in the public
domain' other investigators em obtain funding to analyze them. Because Be observing programs are publicly
known even before the observations are carried out investigators em plan them to apply for support to begin
analysis immediately Her He proprietary validation period has ended. STSeI finds thy the typical datum (one
image or spectrum) is used in ~ least several separate investigations beyond that of the original observer. The
accumulated download of dam is mmy times larger than the tool amount of dam in the archive. This archival
research has led to major discoveries Ad also has dramatically improved He plying for future missions.
The success of astrophysical archives has given bird to the National Virtual Observatory ( - O) initiative
that should make the archives even more productive in the future.26
In solar system exploration' examples of the value of archives are diverse. The Geosciences Node of He
Plme~ry Da~ System' for example' digitized the microfilm d~a from He Viking Labeled-release Experiment
SOLAR ~~M E~LORANON TODAY
thus Idling ~ new t~ of investigation searching for evidence of circadian rhythms in ~e dam. The Small
Bodies Node (SON) provided archival in~rpre~tion of ~e Gio~o trajectory for art investigator Peking to discover
if ~e nucleus of Comet Grigg-Skjellerup is binary. The archives are also used extensively for plarming future
missions, all the way from the proposal stage through devils of spacecraft arid mission ~sign. ~vestig~ors have
written lepers to ~e SON highlighting how Hey have used ~e online do particularly the database on Ear~-
based comparative dam on domed arid asteroids' to Flare Discovery program proposals.
Solar system exploration missions operas entirely differently from ~e Greg Observatories in marry ways.
The missions And to ~ of fixed duration' arid all but the Flagship missions usually have short lifetimes ~~ make
it impractical for the mission Cams to eider develop or maintain ~ longhorn archive. The mission Cams rarely
have arty expertise in archiving, Id the dam produce from ~e Cams often have grossly different formed win
widely varying degrees of documentation. Furthermore' solar system exploration missions do not themselves
include extensive, funded programs for guest observers, who effectively serve as user-reviewers of ~e archival
pipeline. Da~-ar~alysis programs' established to allow research on the information returned from solar system
exploration missions' have been hit-or-miss, often underfunded' of too short duration (e.~.' the Venus D~-
An~ysis arid Jupiter Da~-An~ysis programs), or nonexistent (e.g.' the Galileo Europa arid Millermium Mission
extensions). On over occasions, funding is delayed to such art exams thy research programs risk losing momen-
tum (e.g.' for the NEAR mission).
To obtain Be maximum value from the scientific dam returned from solar system exploration missions' it is
essential to properly execute two intimately related activities. The first of these is to ensure that the archiving
entity, the Plme~ry Da~ System' has the necessary resources for the job md is heated as ~ important scientific
component of each mission from the outset. The second is to dramatically improve Be d~-~alysis programs.
SAMPLE-llETl3RN FACILITIES
As part of NASA,s Solar System Exploration program' samples will be returned from extr~errestria1 bodies.
Sample-return missions already under way include Be S~rdust md Genesis missions of NASA md the MUSES-C
mission of Jacobs Institute of Space md Ashonautiea1 Sciences (ISAS). Samples from these missions carry
plme~ry protection designation of Restricted Earth Return. They will be curded in dedicated facilities
the Johnson Space Center md distributed to qualified scientist for investigation. Samples returned from objects
of biological interest (e.g., hears md Europa) are subject to quarantine restrictions in ~ sample quarantine facility
that em preserve the pristine nature of the samples md prevent back-eon~mination of Ear.
Mars Quarantine Facility
Sever al N1~C studies outline the contingent requirements for samples returned from h~rs.29 Win the
exception of samples returned from Europa, Were are few constraints on samples returned from small solar system
objee~.~° The recent N1~C report on the Mars Quarantine Facility ~0F) stresses that ~ minimum of 7 years will
be required for Be design, eonshuetion, md commissioning of Be M9F, md that it must be operating up to 2 years
prior to the arrival of martim samples. The purpose of the M0F is threefold: to sequester unaltered samples until
hioh=ard testing is complete' to preserve the pristine nature of the samples' md to release samples deemed to be
nonhazardous to ~ sample eur~ion facility for allocation for further scientific study.
The technology required for containment md asking for pathogens is well developed. Biohazard assessment
mud also consider Be potential ecological Bread posed by returned samples. Sample containment must preserve
the samples in ~ pristine condition' without inorganic md organic eontamin~ion. Technology for He preservation
of samples similar to thy used for lunar samples in He Lunar Cur~oria1 Facility ~ the Johnson Space Center is
well developed. However' He eombin~ion of biocontainment md preservation of samples in their pristine
condition requires ~ unique design for He M0F that no currently existing facility provides. Another important
design feature should be the potential for expansion, if early findings of definite evidence of extraterreshia1 life
warrmt the need for all studies to be performed under eontainment.~i The cost of building such ~ specialized
quarantine facility needs to be investigated.
770
HEW FR0~ IN =E 50~R HIM
In addition to Walloping ~e Ethnology to satisfy the design constraints for ~e M9F, it is also importmt to
initiate ~ program to Dunlop key research arid ar~al~ica1 tools. These include' for example' the development of
criteria for ~e following:
Biohazard assessment,
Definition of life arid of standards for life detection thy minimize sample sin requirements'
S~riliz~ion of samples for po~ntia1 early release' arid
Re1~e from con~inmmt of samples deemed to be safe.
A vigorous research arid ar~alysis program must address Base issues:
Enhanced sterilization techniques thy will minimally compromise ~e interim of returned samples' arid
Highly sensitive techniques for life detection.
The sample-h~dling requirements for geochemic~ arid biological investigations arid for specific biohazard
Aping are not necessarily compatible. The NRC has recommended thy ~ advisory commi~e oversee ~e design
arid construction of the MQF arid ~~ this group "will be ultimately responsible for ~e disposition arid handling of
samples in the MQF until Hey are judged to ~ safe for release.~32 This committee should also be cognizant of ~e
processes for collecting ~e samples on hears md for allotting the samples for scientific study once Hey are
released to the Mars Curatorial Facility. The SSE Survey endorses the Unkept that ~ single advisory structure
supervise ~11 mpecis of resumed Mars sample ~lle~ion' containment' ~ara~eri~tion and hamrd =sess-
ment' and allocation. This advisory structure might he international in composition+
Sample Curatorial Facilities
To preventcross-con~min~ion between samples from different plmet~ bodies, the samples mud be handled
in separate facilities. The Mars Curatorial Facility' for example, will be required once He martim samples are
shown to be environmentally safe. Construction of such ~ facility is considered to be consistent with current
practice md experience' for example' for lunar samples md Antarctic meteorites. Sample allocations from He
Lunar Curatorial Facility md from the Antarctic Memorize Laboratory are under He guidance of advisory
committees (the Cur~ion md Analysis Plying Team for Exhaterreshia1 Materials md the Meteorite Working
Group). These advisory committees are the successors of the Lunar Sample Analysis Plying Team, which
oversaw the preliminary examination of the returned lunar samples md lunar sample allocations. These eommit-
tees best exemplify the advisory commits proposed above for the oversight md analysis plying for Mars
samples.
The Need for an Early S~nple-lletum Progrmn
When addressing the future of solar system exploration' it is clear that ~ natural process of maturation he
occurred. Missions have progressed from recormaissmee flyby md orbiter missions, to deviled eharaeteriz~ion
from more sophistiea~d' long-lived orbiters md from landed missions with in situ investigations, to sample return
from small bodies' md finally to future sample-return missions from planets' comet surfaces, md asteroids.
Science questions tied to samples returned from diverse planetary environments form ~ prominent theme in He
individual panel reports of Part Me that lead to mmy of the specific mission recommendations for He next decade
(see Shaper 8~. This recurring emphasis on sample return is ~ direr result of He sophisticated level of scientific
questions thy em now be posed md answered. There is nevertheless ~ host of interwoven issues md requirement
for each of the sample-return missions' mmy of which would benefit from ~ thorough md in~gra~d approach.
SOLAR ~~M E~LORANON TODAY
777
These issues were addressed by some of the parted reports (see, for example' Shaper 2~. The broad common
categories the mud be addressed by each mission include the following:
Consideration of the metros by which ~ sample is acquired md returned to Earn. Although each perry
environment is different ~e Ethnology required for implementation often applies to more chart one situation.
Experience gained in one environment may provide valuable benchmarks for armorer. Examples include Best:
Experim~ win end-to-=d ~qumcing for lunar sample acquisition would provide confidence in under~k-
ing the more complex Mars sample return;
The architecture for returning samples from ~e Mars graviW-well could be comparable to ~~ needed for
similar Venus activity; arid
Anchoring ~ spacecraft on arid Squiring samples from ~ low-density' near-Ear~ object would provide
experience needed for similar activities on ~ complex' multiphase comet nucleus (or vice versa).
Requirements for the development arid Ming of Earth-based' ~~-of-~-art ar~al~ica1 capabilities
to study the returned samples. Instead of developing instruments for launch into space, extremely capable arid
sophi~ic~d instrument must be developed for use in Earth-bamd laboratories for dam acquisition arid ~e
extraction of science information from ~e returned samples. A review of the ar~al~ic~ capabilities in U.~.
laboratories for sample analysis he identified the need for the development of new instrumentation arid for
upgrading U.S. laboratories. In response, ~ start in this direction has been made by the new arid fully competitive
Sample-lleturn L~or~ory Inshumen~tion md D~a Analysis Program. There is ~ need to improve md to
develop, on ~ continuing basis' novel' sensitive instrumentation md to develop He mal~iea1 techniques applicable
to specific samples md new science questions. The development of ~ specific instrument normally takes ~ to
7 years. Gaining experience md developing techniques for such ~ instrument require ~ additional ~ years.
While some instruments may become commercially available, it is more likely ~~, with adequate support' key
novel instrument will be developed Trough the close interaction between industry md researchers.
Need for appropriate mal~iea1 facilities Song wig persormel who have the expertise to use them. Diverse
instrumentation is necessary for sample Keynes. For major instruments' it is likely ~~ Me use will be shared by
mmy investigators md ~~ such instrument may reside in regional Centers of Excellence md require ~ facility-
type operation. It is anticipated Host of these regional facilities will be assoeia~d with edue~iona1 institutions
md will help chin multidiseiplin~ researchers. It is recommended ~~ these mal~iea1 capabilities md experience
working wig very small samples be developed well in advance of sample return.
~ Need for planetary protection md eur~oria1 facilities to contain samples md for procedures to handle
diverse samples. Such facilities for lunar samples are greedy in place md in use. Facilities for Me Discovery
missions Stardu~ md Genesis are under design. Appropriate facilities for diverse samples from environment
with biological po~ntia1 as well as from environments whose in~grily must be mainlined le.g., temperature'
pressure' composition) need to be implemented md sample-h~dling experience gained well in advance of sample
return.
As we enter the detailed exploration phase of planetary exploration, sample return of the basic `
779
HEW FR0~ IN =E 50~R HIM
PUBLIC RELATIONSHIPS+ OUTREACH AM EDI}CATION
NASA has men engaged in education arid public outreach activities since its inception in 1958. During ~e
mid-~9Os' ~e NASA Office of Space Science formalized ~ E/PO scraggy ~~ includes education communities'
space scimlis~, arid relend NASA org~izations.33 The implementation of this strategy was formulated by art
E/PO Task Group appointed by ~e Space Science Advisory Commits. A key element of ~e implementation is
to ``leverage,' activities Trough collaborations with other orgar~iz~ions arid institutions, such as plar~aria. An
in~gra1 pad of OSS,~ E/PO goal includes Gaining activities to help create ~ scientific workforce for the future.
The program is well conceived to achieve Base goals md on its way to Wyoming ~ hallmark for other governmental
agencies.
The OSS ElPO is orgar~i~d into four forums, each of which corresponds to OSS themes including Solar
System Exploration (S SE). The SSE ElPO forum, direc~d through the ~t Propulsion L~or~ory' provides
sustained afford arid continuity of educations activities beyond Hose of short-~rm missions or wlivities under-
taken by individual researchers. Part of the OSS EiPO Program is the concept of Brokers which are regional
centers win ~e goal of interfacing between ~e needs of various ElPO ventures arid perry scimlis~.
The OSS EiPO sponsors ~ wide variety of activities arid collaborations, implemented Trough missions'
research activities' formal education projects' md informal projects. For example' in He year 2000, some 614 evens
for educators were held across solar system exploration activities arid involved more ~m 42~000 attendees; in
addition' more than 600 public events were held, reaching more than 662~000 participant. Concurrently, 85
permanent museum exhibits were supported' md ~ ~ traveling exhibits involving solar system exploration were
developed.
Plenary missions provide ~ unparalleled opportunity to capture student md public attention in science'
engineering, md exploration. llecognizing this high potential' all NASA flight programs are required to Devon
~ to 2 percent of their total budget to ElPO. Typically' each flight project develops its own set of Utilities. The
EiPO component developed Trough principal-investigator-led flight projects' such as Discovery missions' have
been particularly effective. ~ these projects' ElPO is typically <
SOLAR ~~M E~LORANON TODAY
773
system exploration should ~ incorporated into undergraduate arid gradual curricula. This could be achieved by
working closely with authors arid publishers of textbooks, including offering help ~ the review stages of
publication.
One significar~t issue ~socia~d with the various science principal investigator (PI)-led EiPO efforts is the
general lack of recognition by institutions arid peers for EiPO activities. Considerations of promotion arid Inure
place little weight on such wlivities' arid ElPO publications are seldom considered to be significant in ~e PINS
publication record. Consequently, mod PIs conduct EiPO on the side' because Hey feel it is important, but
underfed ~~ Heir efforts are unlikely to be recognized or rewarded.
Most of ~e current SSE ElPO principal-investig~or-led activities appear to be focused on teachers arid
studded' with relatively little attention given to the general public. Some perry scientists noted thy research-
linked ElPO proposals for activities focusing on the adult population tend to ~ rejected within ~e current SSE
EiPO framework. Although it is recognized ~~ ~e OSS ElPO sets ~ priority on educating leachers md students'
it is also importmt to educate ~e general population about broad science topics md more specifically' solar system
exploration goals arid results. Enabling inversions with active ply scientists could ~ very effective for this
purpose.
Nearly everyone agrees thy having art ElPO program within S SK' arid particularly the involvement of PIs is
good. However, marry ply scientists view ~e SSE ElPO program as being excessively bureaucratic'
especially when the broker-facili~tor system is Eked into account. Although marry PIs consider this system to
have merit in principle' Hey see it as ineffective in practice. Moreover' it is nof clear how ~e lines of responsibility
are drawn between NASA's Public Information md Education md Public Outreach offices or how He various
activities are coordinated.
The requirement of incorporating EiPO for specific projects, such as Discovery missions, is considered
meritorious, md most plenary scientists agree that He current funding levels of ~ to ~ percent are about right
within He SSE program. In most implementations' planets scientist md education specialists work h~d-in-
h~d to derive irmov~ive md effective activities for communicating solar system exploration to students teachers'
md the public. In mmy respects these programs mrve as models for SSE EiPO in general. ElPO Utilities
proposed as part of the overall research program, however' have not worked very well' primarily because of He
review process md the lack of sufficient funds. For example' mmy PIs put subs~tia1 effort into preparing
<
774
HEW FR0~ IN =E SOLAR IBM
S. Spam Studies Board Id ~ card ore Life Skiers N~ior~:~1 Monarch Cour~cil' Life i~ ~e Berm An AN of Us a
brows Program `~A~trob~olo~' N~ior~1 Academies Press' Washir~or~' D.~.' 2003.
?. H. Strughold' ~e Frees a~ Re1~t Ur~iversity of New Mexico Press' Albuquerque' 1953.
10. For :~ flour examir~ation of NASA>s A~robiolo~ programs see' for example' Spam Studies Boards N~ior~:~1 Research Cour~cil' Life
Unnerve An AD of ~ s a~ I~r~ho ~l Programs ~~ A~trob~olo~' National Academies Press' Washir~or~' Date.' 2003.
~ ~ . ~ . J~kosky et al.' 1lThe Role of Askobiolo~ ire Solar System Explor~ior~: A Sport from the NASA A~robiolo~ Coitus to the
N~ior~:~1 Monarch Council Solar System Explor~ior~ Dec:~da1 Straws Working Group>~' NASA A~robiolo~ Ir~itu~' Coffey Field'
Califorr~ia; white paper available orally ~ ~h~p:~r~re.colorado.edullifelMAI-report-to-NRC.html>.
~ 2. Executive Office of the Pre micra o f the Ur~i~d Stand' Budget of ~e US Oover~t—F`~l Year 2003' U .S. Goverr~mert Prirt~g
Offing Washin~or~> D.~.' 2002. Available online at ~h~p:ilwww.whitehou~.goviomb~ud~tify2003~ud~t.html>.
~ 3. Spam Studies ~ oard' N~ior~1 Research Councils An ~~r~r~y for ~e P~ry SO 1995-2010' N~ior~1 Academy
Press' Washir~or~> D.~.> 1994.
14. See' for example, SEC Roadmap Team' Su~-~arth Coo Romp 2003-2020' NASA' Washir~or~' D.~.' 2002.
~ S. Spam Mu dies ~ oard' N~ior~1 Research Cour~cil' $~e Management ~~ ~e Hu~ Polo of Space' Natior~1 Academy Pre ss'
Washir~or~> ~ .O .> ~ ?97' pp . ~ 3- ~ S.
16. Spam Studies Poard' N~ior~1 Research Council, ~e Hu~ Polo of spars' N~iona1 Academy Press' Washington' Deco.>
1997.
17. Aeror~autics md Spam Er~gir~er~g Board Ad Spam Studies Boards N~ior~1 Research Councils safe on Apart> N~ior~1 Academy
Press' Washir~or~' D.O .' 2002.
18. Spam Studies Board' N~ior~1 Research Councils $~c Prerequ~ for ~e ~~ Pork of space' N~ior~1 Academy
Press' Washir~or~> D.~.> 1993.
19. See' for example' Spam Studies Board' Natior~1 Research Council, Supports Rehears a~ Da~ AS t~ NASAL Sconce
Programs E~ of Jo ~ a~' Natior~1 Academy Press' Washir~or~' Deco.' 1993 .
20. Executive Office of the Pre micro of the Untied Stays> Budget of ~e Us Oover~t—F`~l Year 2003> U.S. Govemme~ Priming
Offing Washin~or~> D.~.> 2002. Available online at ~h~p:ilwww.whitehou~.goviomb~ud~tAfy2003~ud~t.html>.
21. Spam Studies ~ card' Natior~1 Research Councils Supports Radars a~d BAJA A~ t~ BASALT Scte~e Program E~ of
Proved on a~ ~~> N~ior~1 Academy Pre ss, Washir~on' D.C .' ~ ?~S .
22. Spam Studies ~ oard' Natior~1 Research Cour~cil' Supportive Ternary a~d Da~ A~ ~~ BASAL Sc~e Program E~ of
Doodad on FEZ ~~' N~ior~1 Academy Pre ss' Washir~on' D.O .' ~ ?98 .
23. Spam Studies ~ card' Natior~1 Research Cour~cil' Supporting Regears a~d Da~ A~ ~~ BASALT She Program E~ of
Proved on FEZ ~~> N~ior~1 Academy Pre ss' Washir~on' D.C .> ~ ?~> pp . 48-50 .
At. Spam Studies ~ card' N~ior~1 Research Councils Am of ~e we~ a~ Aims of HASA ,~ Bard a~ Space Scow
M`~o~ Da~ N~ior~:~1 Academy Press' Washir~or~' D.~.' 2002> pp. 68-~.
25. Spam Studies Bo lard' N~ior~1 Research Councils Sc`~c Opportu~ ~~ ~e Huma~ Exploration of Space' N~ior~1 Academy
Press' Washir~or~' D.C .' ~ ?~' pp . ~ 2-13.
26. hive details Gout the N~ior~:~1 Virtual Observatory c~ be found online ~ ~http:~/www.us-vo.or~.
hi. NASA MPG Report ~ 999> P~ryPro~`o~Prov~o~forTobodc~tr~erre~tr~lM=`o~> NASA MPG 3020.128> N~ior~1
Aeronautics Ad Spam Admir~i~r~ior~' Washir~or~' D.~.' 1999.
28. L. Oral, he. A>Hearr~' J. Bada' J. Baross' C. Chapman' ha. Drake' J. Kerrid~' ha. Race' ALL. Sogir~' md S. Squyres' resample Retum
from Small Solar System ~ Odin A~ ~~ Space Ternary 25: 23 ?-2A3> ~ Add.
29. See' for example' Spam Studies Board' N~ior~1 Research Councils ~e Ire a~ Cert~to~ of Martyr Samples' N~ior~1
Academy Press' Washir~or~' D.O .' 2002.
30. L. Oral' he. A>Hearr~> J. Bada' J. Baross' C. Chapman> h4. Drake' J. Kerrid~> h4. Race' ALL. Sogir~> md S. Squyres' resample Retum
from Small Solar System ~ Odin t~ Space Rewarm 25: 23 ?-2A8' ~ Add.
3 ~ . Span Studies ~ o lard' N~iona1 ~ march Councils ~e Ire a~ CerEficaho~ of Martian Samples' Natior~1 Academy Press'
Washir~or~> D.~.> 2002.
32. Span Studies B oard' N~iona1 ~ march Councils ~e Ire a~ C:erkficaho~ of Martian Sample' Natior~1 Academy Press'
Washir~or~' D.~.' 2002.
33. Office of Up: Science> N~iona1 Aeronautics Ad Span Admir~i~r~ion' Imp ~e Offer of I t05~ Who
PabEc Outreach Strategy' Natior~1 Aeronautics Ad Span Admir~isk~ior~' Washir~gtor~' D.~.' 1996.
34. N~ior~:~1 Research Cour~cil' strop ~e Nat~o~l She Into SO N~ior~1 Academy Press' Washir~on' Dog.>
1997.
