Carl Sagan Center Projects

"Exobiological Investigations of Perennial Springs in the Canadian High Arctic"
Dr. Dale T. Andersen

Perennial springs located at Axel Heiberg Island in the Canadian High Arctic provide useful analogs to liquid water habitats that may have existed on Mars. The springs occur in a region with a mean annual air temperature of -17C, and thick, continuous permafrost breaching depths of 400-600 meters. Spring flow rates and discharge temperatures are constant throughout the year. Filamental bacteria, biofilms, and mineral precipitates occur in association with the emergent, anoxic brine flowing from the springs. This low-temperature setting provides an example of hydrothermal systems operating in the presence of thick permafrost-as would be expected to have been present on Mars during an earlier, more habitable period. This research examines the microbial communities found in association with the springs located at Axel Heiberg. The composition and distribution of the microbiota along environmental gradients particularly with respect to changes in redox, pH, temperature, light and dissolved gases will be characterized. This characterization will involve the application of both culturing and culture-independent approaches. This will allow us to determine the abundance of microorganisms, their phylogenetic identity and their possible physiological function within the spring system and the run-off areas. The travertine and other precipitates will be examined microscopically for microfossils which may have been preserved within the mineral matrix. Data obtained from this work will lead to a better understanding of the adaptive strategies used by microbial life found in extreme polar environments. On Mars, protected subsurface niches associated with hydrothermal activity in conditions of thick, continuous permafrost could have continued to support life even after surface conditions became inhospitable. The research at Axel Heiberg springs will provide information relevant to the search for evidence of life on Mars. Insight gained from the study of terrestrial polar spring environments will help guide the site selection of targets of exobiological interest and will aid with the interpretation of data returned from missions to those sites. NAG5-12395

The Formation and Evolution of Planetary Systems: Placing Our Solar System in Context
Dr. Dana Backman

We plan to trace the evolution of planetary systems at all ages ranging from: (1) 3-10 Myr when stellar accretion from the disk terminates; to (2) 10-100 Myr when planets achieve their final masses via coalescence of solids and accretion of remnant molecular gas; to (3) 100-1000 Myr when the final architecture of solar systems takes form and frequent collisions between remnant planetesimals produce copious quantities of dust; and finally to (4) mature systems of age comparable to the Sun in which planet-driven activity of planetesimals continues to generate detectable dust. Our strategy is to use carefully calibrated spectral energy distributions and high-resolution spectra to infer the radial distribution of dust and the molecular hydrogen content of disks surrounding a sample of 300 solar-like stars distributed uniformly in log-age over 3 Myr to 3 Gyr.

The high precision and fine sampling of Spitzer spectral energy distributions can reveal both the existence of planets and their approximate masses and radial distributions through modeling of the dynamic effects of planets in sculpting planetesimal distributions and orchestrating their collision frequency. The size of our target list will enable us to characterize the diversity of planetary system architectures, providing a deeper appreciation of the range of possible outcomes of the planet formation process -- thus placing our own solar system in context.

Our Legacy program promises to provide: (1) new insight into problems of fundamental scientific and philosophical interest; (2) calibration with precision 2-3 times that of standard Spitzer data products, to the benefit of all Spitzer observers; (3) new numerical tools for simulating the dynamic history of forming solar systems; and (4) a rich database to stimulate follow-up observations with Spitzer, with existing and future ground-based facilities, and later with SIM, NGST, and TPF.

"A Prebiotic Photochemical Study of Early Earth"
Dr. Emma Bakes

A hydrocarbon haze such as is evident around Saturn’s largest moon, Titan, dominates the host planet’s atmospheric temperature, circulation and climate control. This haze is postulated to have existed via methane photolysis in the atmosphere of the early Earth. In this project photochemical models of the Titan haze which were built in previous research by the PI and collaborators, will be adapted in order to understand chemical processes important for the formation of nitrogenated aerosols and macromolecules in the reducing atmosphere of early Earth. Models of hydrocarbon haze charging and infrared (IR) emission will be used to analyse chemical and IR spectral data from laboratory-based simulations of the primitive terrestrial atmosphere. How a hydrocarbon haze might have shielded important greenhouse gases, such as ammonia, and how these gases might have contributed to the heating of the atmosphere via the photoelectric ejection of energetic electrons (which might mitigate the anti-greenhouse effect introduced by the haze as it is a powerful heating mechanism) is being investigated. The goals of this project are: 1) to adapt existing models to physical conditions (UV field, electron density and gas temperature) appropriate to the primitive atmosphere of the early Earth; 2) to support complementary laboratory work analyzing the macromolecular and submicron aerosol components postulated to exist in this environment; and 3), to investigate the relevance of our photochemically produced nitrogenated heterocycles to prebiology. They form the foundations of cellular metabolism and reproduction and by investigating their formation pathways, we can understand the bridge between prebiological chemistry and biochemistry. NASA Cooperative Agreement NNG05GQ68A

"Biosphere of Mars: Ancient and Recent Studies (BioMars)"
Dr. Janice Bishop

Mars is an exciting, and comparatively accessible target for astrobiological studies aimed at detection of current or past extraterrestrial life. We are analyzing the evolution of the Martian hydrosphere and surface topography to understand the history of water distribution and investigate atmospheric processes that may have contributed to a UV shield. Our goal is to identify the types of sites on Mars that experienced long-term fluid flow and may be, or have been, conducive to life. We characterize biomes that develop in analogous Earth environments, conduct experiments to determine limitations for life in these habitats, and identify features that constitute indicators of life. We propose robot-based sampling and in situ analyses of terrestrial sites so as to develop methods for dealing with the challenges of remote geomicrobiological investigations. Our work will provide constraints for selection of optimal sites for future Mars exploration and methods for sample analysis, and ultimately will be relevant to the question ‘did life evolve elsewhere in the universe’.

The portion of this project led by Co-I Bishop involves remote characterization of the mineralogy of Mars including providing constraints on the mineralogy and physical properties of materials in channels on the Martian surface. The in situ spectral measurements are performed using visible/IR reflectance spectrometers in the lab and in the field of minerals and Mars analog materials. These spectra are convolved to the spectral resolution of OMEGA on Mars Express and CRISM on MRO for comparison with those instruments. Spectral image analyses are underway in order to identify minerals on Mars associated with living systems. For this project there is an emphasis on Fe- and S-bearing minerals.

SETI Grant # 325 via a subcontract from University of California Berkeley, NASA funding from the NAI.

"Martian Surface Composition and its Practical Applications to Astrobiology"
Dr. Janice Bishop

Martian surface alteration processes are under study through analysis of spectral, magnetic and chemical data from Mars and analysis of analogue materials in the laboratory. The kinds of Mars surface analogues studied include Martian meteorites, volcanic tephra, sediments from the Dry Valleys region of Antarctica and hydrothermal rocks. Pure minerals, such as iron oxides, sulfates, carbonates and silicates, found in these samples are studied, as well, in order to better characterize and identify them or related materials on Mars. Many of these minerals are associated with organisms and may be useful as indicators of life or environments supportive of life on Mars or other planets.

An important component of studying alteration processes on Mars is addressing the question of chemical alteration and water. There has been much speculation about the presence of water on Mars based on geomorphology. Many kinds of chemical alteration require liquid water, and hence, identification of minerals produced through aqueous processes would provide another line of evidence for the putative liquid water on Mars. Identifying minerals and/or processes requiring the presence of water will have important implications for Astrobiology on Mars.

A number of the minerals and phases studied as potential Mars analogue materials contain nanophase components and will utilize new forms of nanotechnology. These materials may have formed through alteration of volcanic material or precipitation in hydrothermal springs. Nanophase silicate fragments and/or ferric oxides and hydroxides frequently comprise these materials and are consistent with many of the properties of the dust on Mars. Research covered by this Cooperative Agreement includes characterizing the spectral, chemical and structural properties of nanophase silicate and oxide minerals.

The primary task under this Cooperative Agreement is for work funded by Dr. Bishop as a Co-I on the CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) team, where Dr. Bishop is leading the spectral identification tasks related to hydrated minerals and surface alteration. Additional tasks are for work funded through the ASTID and MFR programs. Tasks in this Coop also involve the design and construction of instruments for Mars missions in collaboration with Dr. David Blake, via subcontracts with Apparati, Inc. and InXitu. NNA05CS53A

"Taking Apart the Rocks of Mars"
Dr. Janice Bishop

Evaluation of the mineralogy of the surface of Mars is a fundamental goal of Mars exploration and is a requirement for understanding geological processes active on the surface. Remote sensing techniques, principally visible/near-IR and mid-IR spectroscopy, are the primary tools used to achieve this goal, supplemented by in-situ analyses including Mössbauer spectroscopy. This project involves identifying and investigating the diagnostic properties of a suite of mineral separates from actual Martian meteorites using a wide range of spectroscopic techniques in a systematic and integrated manner. This set of well-constrained diagnostic properties of Mars materials (coupled with existing spectral data for terrestrial materials and Mars analogues) form a consistent and reliable foundation upon which to explore the mineralogy of Mars with a host of sensors active or soon to be active at Mars. Co-I Bishop is focusing on linking the mineral structure to specific vibrational absorption bands observed in the infrared spectra of several silicate minerals.

SETI Grant # 324 via a subcontract from Brown University, NASA funding from MFR program.

"From Habitability to Life"
Dr. Nathalie Cabrol

Building upon the results of the MER mission, and of our theoretical, experimental, and field work in high-altitude lakes, we bring the focus of this new proposal to the transition from habitability to life. The MER mission has demonstrated that Mars was habitable for life as we know it (in its microbial form) in its early geological history. But habitability does not equate to life, and critical questions have yet to be answered. A sample of those are:

Did the transition happen?
What was the biological potential of Mars?
What were the environments where life could have had the mostly likely chance to develop and, perhaps, survive?
What kind of extreme conditions did life face?
What types of adaptation and survival tools and skills could life have used?
If Mars developed life, can we still find its geological, mineralogical, or biological signatures today, whether it is extinct or extant?

This project plans to document critical aspects of those questions and presents a synergetic research focusing on the theme of the transition from habitability to life from various and complementary perspectives as shown in the four tasks summarized in the following table:

Task and Sub-Task No.	Title	Lead
1. Exploration and Characterization of the Surface of Mars
1.1	Mars MER investigation and rover surface operations	N. A. Cabrol
1.2	Geological investigation of Mars from orbital remote sensing: Topography and basin deposits of the Martian highlands	J. M. Moore
2. Experimental Studies of Brines and Evaporites as Applied to Mars
2.1	Brine formation experiment	J. M. Moore
2.2	Mars-Analog evaporite formation experiment	J. M. Moore
3. Potential Habitats and Life Adaptation Strategies Against Environmental Extremes Relevant to Mars: Their Characteristics and Signatures
3.1	Effect of high-UV radiation on life in high-altitude lakes: Analogy to Mars	N. A. Cabrol
3.2	Biological and geological signatures of extreme microbiolites in early Mars analog environment	N. A. Cabrol
4. Development of Detection Strategies for the Robotic Search for Life on Mars and Applications to Upcoming NASA Missions
4.1	Robotic astrobiology (the Life in the Atacama “LITA” project)	N. A. Cabrol
4.2	Analysis of science operations for the search for life on Mars	N. A. Cabrol

NNA05CS77A

"Science on the Fly: Enabling Science Autonomy During Robotic Traverse wiht Application to the Study of Life in the Atacama Desert of Chile"
Dr. Nathalie Cabrol

Currently, rovers can travel tens of meters per sol, but the next generation of rovers is predicted to be able to traverse ten or more times as far. This capability presents a situation in which the rover will be able to travel to places about which it has no information and which it was not able to see at the beginning of the sol. This presents us with not only an exciting opportunity but also several challenges. This situation will require the rover to use methods for performing effective science when the rover has left the area that was initially visible and is out of contact with scientists.

The "Science on the Fly" software consists of two principal parts, the science observer and the science planner. The science observer acts as the rover's eyes and ears. The science observer interprets sensor data to find possible targets of scientific value. The other part, the science planner, takes the observations made by the science observer and plans experiments that would be of maximum scientific value.

Science Observer

The Science Observer serves two major roles: identifying targets of interest and categorizing them into useful groups. For example, the most prominent targets for geological study are rocks. When the science observer examines an image, it looks for rocks using a "machine learning" algorithm that has been trained ahead of time to recognize rock-like features. Then, it autonomously categorizes those rocks into groups based on data it has seen before. In this manner, the Science Observer can recognize novel rocks as well as perform automatic geological analyses. Besides rocks, targets of scientific interest could include lichens or patches of soil.

Science Planner

The Science Planner enables the rover to react to new science opportunities as it moves into unexplored areas. The Science Planner accepts priorities from the science team, such as "carbonate rocks are important to sample." Then, when the Science Observer detects a high-priority, interesting feature, the Science Planner tries to make a plan for getting more useful information about the feature. For instance, it might move closer and examine the feature with its fluorescence sensor to look for signs of life. It is not always easy to generate this kind of plan because examining every interesting feature would take far more time and energy than the rover has available. CMU110079-150783

"Survey and Exploration of Environments Favorable to Water and Life on Mars and Their Terrestrial Analogs"
Dr. Nathalie Cabrol

This project focuses on the survey and exploration of aqueous environments that might be favorable to life on Mars and the investigation of terrestrial analogs. To achieve this goal, we propose synergetic research focusing on this theme from various and complementary perspectives that we will initially organize into three tasks, with the possible addition of a fourth task, pending approval of funding:

Task 1 characterizes the Martian ancient and recent, possibly current, aqueous environments. This task is the follow up on our previous years' investigation of aqueous environments at Viking resolution. This research debouched on the production of the first impact crater paleolake catalog. It expands with this proposal in three direction: (a) the study of the deltas that we identified while completing the catalog, (b) the characterization of recent aqueous environments (e.g., glaciers, rock glaciers) that we discovered while surveying the Mars Global Surveyor MOC image archives. This characterization is an essential step in our research as one cannot understand the past water history of Mars if the clues for potential current activity are not deciphered, and (c) the reconstruction of ancient basin dynamics through the evaluation of the sequence and extent of various landform-modifying processes that have shaped several regional areas of topical interest in the Martian highlands.

Task 2 characterizes the Martian fluids and the chemical sediments that could potential have formed in the basins we identified and new ones discovered by the Mars Global Surveyor mission. This task is a natural continuation of Task 1. The nature of evaporites formed under Martian conditions is poorly understood. Laboratory studies investigating the formation of brines and evaporites would greatly aid in improving our understanding of these materials. To date, only a very limited number of laboratory investigations have been conducted which have any bearing on a better understanding of various processes related to evaporate and brine formation or characterization on Mars. It is also an essential step to better understand the astrobiological potential of these sites for future exploration.

Task 3 will provide the ground-truth necessary to collect the data to support our observational and theoretical research on Martian aqueous environments. This task is focusing on the acquisition of data in terrestrial analogs to surveyed Martian sites. It includes the investigation of sites which each carries a critical element of information to better understand various Martian aqueous environments and more efficiently prepare the future missions. Two of them are specifically investigated as a support to the 2003 Mars Exploration Rover (MER) missions. They are: the Licancabur hydrothermally heated crater lake and the El Lago hematite site located within 100 km of each other in the Atacama Desert, Chile. The third site is the newly discovered 120-km diameter Woodleigh impact structure that contains hundreds of meters of Jurassic aqueous sediment and provides a relevant testbed for hypotheses regarding Martian impact crater paleolakes. NCC 2-1328

"A Search for Extrasolar Planets from the South Pole"
Dr. Douglas Caldwell

This project proposes to operate a small optical telescope at the South Pole to search for and characterize extrasolar planets. The method is to observe thousands of stars by continuously following a southern Galactic star filed with a CCD photometer, searching for the periodic dimming that occurs as a planet transits its parent star. The South Pole is the best place on the surface of the Earth to detect such planets because of the long winter night, during which randomly-phased transits can most efficiently be detected. Also, the constant altitude of a stellar field at the Pole avoids large daily atmospheric extinction variations allowing for higher photometric precision and a search for smaller planets. This project will increase tenfold the number of extrasolar planets for which transits are observed. Then, in conjunction with follow-on measurements from existing Southern Hemisphere Doppler velocity programs, planet densities can be determined. These data will provide information vital to theoretical models of planetary structure and formation. NSF OPP-012631

"The Evolution of Astrophysical Ices: The Carbon Dioxide Diagnostic"
Dr. Jean Chiar

We have used the Infrared Spectrometer on board the Spitzer Space Telescope to carry out a comprehensive study of the carbon dioxide bending mode absorption feature centered near 15 micrometers in astrophysical ices. Previous observations with the Infrared Space Observatory, together with studies of laboratory analogs, have shown that this feature has strong diagnostic properties. Substructures within the feature are sensitive to the thermal history of the ices and to the formation of linked carbon dioxide/methanol complexes. Both of these molecules are important repositories for carbon in interstellar ices, and their roles in the chemical evolution of the ices and their sublimation products are intimately linked. The abundance of carbon dioxide relative to methanol is diagnostic of key reaction pathways, measuring the relative efficiencies of catalytic oxidation and hydrogenation reactions in cold dark clouds. In regions exposed to the interstellar radiation field, photolytic reactions may contribute to their formation. The distribution of carbon between these molecules may subsequently influence the production efficiencies of more complex organic molecules in regions of active star formation, where the ices are subject to heating, irradiation and shocks. By studying a range of absorbers, from pristine ices in dark clouds to processed ices in the vicinity of embedded stars, we will build a clear picture of the evolution of ices from the interstellar medium to protostellar envelopes and protoplanetary disks. JPL1266411

"Solid State Chemistry in Dense Clouds Along Quiescent Lines of Sight"
Dr. Jean Chiar

We will study the infrared spectra from 5.3 to 21.8 micrometers through dense interstellar clouds, with little or no star formation activity, to assess the early chemistry of molecular cloud dust. Dense clouds produce molecules and ices critical to star and planet formation. The formation of organic compounds in these ices is one of the first steps toward the complex molecular materials needed for life. Infrared spectroscopy provides a powerful tool for the study of the composition and evolution of interstellar ices. The most diagnostic features of solid-state materials occur in the mid-infrared. To date, mid-infrared absorption studies have primarily been toward embedded protostars where the ice may well have been processed either thermally or by far ultraviolet photons from the star. Such sightlines demonstrate a preponderance of simple molecules (water, methanol, carbon monoxide, carbon dioxide, and ammonia) and energetically processed species (nitriles and cyanates) in the surrounding ices, revealing that protostars strongly influence their circumstellar environments. Lines of sight to these objects are unlikely to be representative of dense cloud materials as a whole. A more complete understanding of the composition of dense clouds and their chemical dynamics requires that we also probe lines of sight through the general quiescent cloud medium. We have obtained low resolution spectra from the Spitzer Space Telescope's Infrared Spectrometer in the wavelength region that includes the absorption features of water, methanol, methane, and carbon dioxide, plus high resolution IRS spectra for selected sources, to study detailed band profiles. We will correlate band strengths with the amount of dust obscuration to determine the abundances and densities required for the ice components to appear, and study the chemical changes in molecular clouds as a function of temperature and density. These observations will provide a snapshot of the chemical state of a molecular cloud prior to the formation of stars, and a general baseline for studies of dust chemistry in regions of star formation. JPL1267778

"Unlocking the Mysteries of Interstellar Dust Composition and Icy Mantle Formation with Sensitive Infrared Spectroscopy"
Dr. Jean Chiar

Interstellar dust is ubiquitous, yet its precise composition is still widely debated. The Spitzer Space Telescope's (SST) Infrared Spectrometer (IRS) provides the sensitivity to study previously unattainable lines of sight throughout the plane of the Milky Way Galaxy. We seek to study the hydrocarbon (carbon and hydrogen-containing molecules) and silicate (mineral) dust components of the interstellar medium for 56 lines of sight with varying amounts of dust obscuring the starlight. In addition, we will be probing the dust over a range of Galactic longitudes and latitudes. Specifically, we will measure the absorption features in infrared part of the electromagnetic spectrum. The hydrocarbon absorption features occur at 6.9 and 7.3 micrometers, and the silicate absorption features at 9.7 and 18.5 micrometers. The ratio of the depths of the hydrocarbon and silicate absorption features provides a direct handle on the hydrocarbon to silicate dust volume. It has been previously been noted that the ratio of the depth of the absorption to the amount of dust obscuration is distinct for locations within the Solar neighborhood (about 1000 lightyears from the Solar System) compared to the Galactic Center (which is 30,000 lightyears from our Solar System). Thus, these absorption features and their relative depths will also be related to the amount of dust obscuration and Galactic location. Finally, the silicate mineralogy can be assessed by studying the ratio of the two silicate absorption features, whose relative strengths have been shown to be indicative of olivine-rich or pyroxene-rich silicates. NNA05CS35A

Imaging Polarimetry of Young Stellar Objects with ACS and NICMOS: A study in dust grain evolution"
Dr. Angela Cotera

This project is focused on studying the evolution of dust grains around young stellar objects (YSOs) by obtaining NICMOS polarimetry for 10 objects which span the earliest evolutionary stages, and ACS polarimetry for 8 of the same objects. The science objective is to determine the time scale for the growth of grains from the initial small ISM grains to larger grains, the precursors of planetesimals. Since small grains have a much larger fractional polarization and a steeper wavelength dependence than larger grains, observations of the variation of polarized light as a function of wavelength are a sensitive probe for determining the size distribution as a function of evolutionary state. HST–GO–10178.6–A

"Solar Systems In Formation: A NICMOS Coronagraphic Survey of Protoplanetary and Debris Disks"
Dr. Angela Cotera

Current theories suggest that dust within the early protostellar envelope settles into the disk mid-plane resulting in a dusty circumstellar disk. The goal of HST GO 10177 is to identify and study stars surrounded by disks during what is presumably the planetary formation stage: the T-Tauri (ò1 Myr) to debris disks (ò10 Myr) phase. The observations are technically challenging at NIR and optical wavelength due to the high contrast between the bright central star and the faint disk, requiring observation with the NICMOS coronagraph. The observations are sensitive to the light scattered off the surrounding disk. In the mid-infrared (MIR, ò5-25 micron), recent advances in array technology combined with the availability of large ground-based telescopes (i.e. Keck and Gemini), have made possible subarcsecond resolution direct imaging of the cold dust disks around the types of stars included in the HST survey. The MIR radiation from disks is thermal radiation from dust heated by starlight and/or viscous accretion. Modeling of the MIR emission from previously detected disk (e.g. HR 4796A one of the first evolved disk to be observed by HST), provided compelling evidence that the dust encircles a solar-system-sized hole, within which a more tenuous concentration of hot dust remains close to the star, consistent with the results from HST/NICMOS coronagraphic images. Since different wavelength regions probe different properties of the evolving circumstellar environment, establishing a self-consistent understanding of the formation of these potential planetary systems requires that observations from one portion of the electromagnetic spectrum be reconciled with the results at other wavelengths. HST–GO–10177.8–A

"Outer Solar System Bodies"
Dr. Cristina Dalle Ore and Joshua Emery

This project consists of two main tasks:

One is to collect as much information on the composition of the Solar System bodies for which data is already available or will become available in the near future from both ground and space-based telescopes, as follows, is being conducted by Cristina Dalle Ore:

Bring Pluto into the picture and compare results with Triton: are they really so similar or is there an underlying difference (Charon?) that makes those two worlds two independent problems?
Continue the study of more asteroids as more data become available: our quantitative modeling studies of asteroid spectra allow us to explore the amounts of various minerals present on the surfaces of these bodies, and to search for the presence of organic constituents that may have some connection to the prebiotic history of the Earth.
Investigate more Centaur and Kuiper Disk objects as data become available to learn more about the history of the materials that were condensed at the edge of the Solar System and that can give us hints on the early Solar System evolution.
Pursue previous modeling efforts to determine the surface composition of more of the saturnian satellites. Compare results among neighboring satellites to infer possible interactions.

The other task, conducted by Joshua Emery, is as follows:

This task will investigate the physical structure and composition of several classes of solar system objects. Measurements of thermal fluxes at several wavelengths will provide the means of deriving sizes, albedos, and/or thermal properties of the surfaces of a large number of Kuiper Belt Objects (KBOs), Centaurs, icy satellites of the outer planets, and Pluto. Surface compositions of a moderate number (~30) of asteroids of several dynamical classes (near-Earth, main belt, Trojan, extinct comet candidates), a few of the brightest Centaurs and KBOs, icy satellites of the outer planets, and Pluto will be studied with thermal emission spectroscopy. Reflected fluxes at 3.6, 4.5, 5.8 and 8.0 m m will be obtained for the icy satellites and Pluto as additional constraints on surface composition. The satellites of Saturn will also be studied using near infrared reflectance spectroscopy. This ambitious program is already in progress, and will be carried out using two spacecraft: The Spitzer Space Telescope and the Cassini spacecraft. Spitzer was launched in August 2003 into an Earth-trailing, heliocentric orbit. It is currently functioning well and returning data. The science payload consists of three instruments. The infrared camera (IRAC) collects images in 4 bands centered at 3.6, 4.5, 5.8, and 8.0 m m. For the surface temperatures of most objects in the outer solar system, fluxes measured at these bands will be dominated by reflected sunlight. The infrared spectrograph (IRS) can measure low resolution (R~60–100) spectra over the range 5.3–40µm, and high resolution (R~600) spectra over the range 10–37 m m. Asteroid fluxes in this range are dominated by thermal emission. Small, colder objects in the outer solar system have sufficient emitted flux only at the longer end of this range to be measured by Spitzer. The Multiband Imaging Photometer for Spitzer (MIPS) provides imaging photometry at 24, 70, and 160µm, and very low resolution (R~15–25) spectroscopy over the range 55–96µm. Fluxes of solar system objects are dominated by thermal emission at these long wavelengths. The Cassini spacecraft was launched in 1997, and is due to arrive at Saturn and enter orbit in June 2004. During its mission, Cassini will record images and spectra of the icy satellites of Saturn. The Visual and Infrared Mapping Spectrometer (VIMS) instrument measures spectra over the range 0.3–5.0µm. Radiation from the moons of Saturn is dominated by reflected sunlight over this range.

This work addresses several outstanding problems in planetary science related to each of the specific groups of objects mentioned above, which will, taken together, also provide deeper insights into the origin and evolution of our solar system. NNA05CS63A

"Planetary Surfaces and Atmospheres: a Reprise"
Dr. Cristina Dalle Ore

The solid bodies of the Solar System include the natural satellites of the outer planets, the planet Pluto, the asteroids, the Centaur objects, the Kuiper Belt objects, the comets and Saturn's rings. The study of their surfaces can shed light on their history: how they formed and where, how they developed and interacted with other bodies in their vicinity. The largest of the Solar System bodies are known to have atmospheres, but more bodies might have a tenuous and transitory atmosphere. Furthermore, in the outer Solar System where very low temperatures keep volatile materials frozen, small changes in temperature can trigger exchanges of molecular material between the surface and the atmosphere. The changes in temperatures could be caused by variations in solar activity, tidal and or magnetic interactions as well as other unidentified factors. A well documented example of such interaction between surface and atmosphere is Triton whose surface shows signs of change with a frequency of only a few months. Its albedo changes by a factor of about two in the UV region of the spectrum for causes yet to be known, but resembles the effect of 'snowstorms'.

Titan, one of Saturn's satellites has a thick, opaque atmosphere due to photochemical smog. Windows in the atmospheric spectrum may allow us to have a chance to observe the lower atmosphere as well as the surface and possibly infer their composition. Furthermore, the materials that make up its atmosphere have been reproduced and processed in the laboratory to yield an organic mixture that could make up some of the surface composition of other outer Solar System bodies, tying their histories together.

Europa, the second largest satellite of Jupiter, has been gathering a lot of attention because of what looks like an ocean of liquid water underneath a possibly thin icy crust. Because of the tidal interaction between Europa, Jupiter and the other neighboring satellites, there is enough energy stored in its water to allow for possible forms of life, current or fossil.

Our goal is twofold: to continue gathering, processing and interpreting telescopic observations (both from ground and space), to obtain more information on the composition of the Solar System small bodies, and to infer the relevance of our findings from the astrobiological standpoint. NCC 2-1339

National Field Test and Dissemination Support for Voyages Though Time, A High School Integrated Science Curriculum on the Theme of Evolution
Edna K. DeVore

NASA Astrobiology Institute, the Astrobiology Integration Office, and Fundamental Biology Research at NASA Ames Research Center sponsor this project in order to support the national field test, final revision and dissemination (via educational conferences and sample materials) of Voyages through Time (VTT), a standards-based, high school integrated science curriculum on the theme of evolution. NASA Ames Research Center has been a major partner in this project since its inception, providing in-kind support by selected scientists acting as content experts. The science encompassed by NAI, AIO and FBR is at the core of VTT. This Agreement exists to assure completion of the project and final revision prior to publication. NAI, AIO and FBR would be acknowledged as partners in the published versions, and would have products for free distribution at education meetings, via the web, and via the NAI network of research partners. Supporting VTT offers NAI, AIO and FBR tremendous financial and educational leverage. VTT is a year-long curriculum, rather than a supplementary product. It will be a core course in many US high schools supported by both by the education department at the SETI Institute as well as by VTT's commercial science education publisher. NASA Grant NAG2-6051.

"SETI Institute's Kepler Education and Public Outreach Project
Edna K. DeVore

The SETI Institute, in cooperation with Lawrence Hall of Science (LHS) at the University of California at Berkeley, conducts the Kepler Discovery Mission Education and Public Outreach (EPO) program beginning in October 1, 2002 and continuing throughout the mission development and operational lifetime. The EPO program is anticipated to be completed on September 30, 2012. The Lawrence Hall of Science work for Kepler EPO is led by Kepler Mission Co-Investigator (Co-I), Alan Gould, and the SETI Institute work for Kepler EPO is led by Co-I Edna DeVore. Both Gould and DeVore work closely with Kepler Principal Investigator (PI), Bill Borucki, and Kepler Deputy Principal Investigator (DPI), Dr. David Koch of NASA Ames Research Center, as well as participating scientists, and industrial contractors on the Kepler Mission. NAG2-6066

Projects continued