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PubMed1973

Antarctica as a Martian model.

Previous investigators have reported that the microbiological population of the glacier free valleys of southern Victorialand, Antarctica, is sparse, and that from about 10% of the soil samples examined no micro-organisms could be cultivated. Since these areas are assumed to be more favorable to the growth of terrestrial organisms than any Martian environment, the previous authors concluded that the probability of terrestrial organisms growing on Mars would therefore be so small that sterilization standards could be relaxed by many orders of magnitude. The unsuitability of the Antarctic environment to the multiplication of terrestrial micro-organisms was ascribed by them to limiting amounts of water. We have carried out a survey of a variety of environments in the dry valleys, ranging from mountain crests to valley floors. The main purpose of our investigation was the determination of active microbial multiplication in the soil. A series of techniques was employed which permitted the detection of bacterial growth in situ. All evidence points to an active growth of micro-organisms in the Antarctic soil in all locations which we examined. The measurements were supported by electron micrographs of soil films which showed colonial growth covering soil particles. These findings suggest that Antarctica does not serve as a useful model for the Martian environment in evaluating quarantine standards.

Antarctic Regions↗
PubMed2001

A massive reservoir of low-excitation molecular gas at high redshift.

Molecular hydrogen (H2) is an important component of galaxies because it fuels star formation and the accretion of gas onto active galactic nuclei (AGN), the two processes that can generate the large infrared luminosities of gas-rich galaxies. Observations of spectral-line emission from the tracer molecule carbon monoxide (CO) are used to probe the properties of this gas. But the lines that have been studied in the local Universe-mostly the lower rotational transitions of J = 1 --> 0 and J = 2 --> 1-have hitherto been unobservable in high-redshift galaxies. Instead, higher transitions have been used, although the densities and temperatures required to excite these higher transitions may not be reached by much of the gas. As a result, past observations may have underestimated the total amount of molecular gas by a substantial amount. Here we report the discovery of large amounts of low-excitation molecular gas around the infrared-luminous quasar APM08279+5255 at redshift z = 3.91, using the two lowest excitation lines of 12 CO (J = 1 --> 0 and J = 2 --> 1). The maps confirm the presence of hot and dense gas near the nucleus, and reveal an extended reservoir of molecular gas with low excitation that is 10 to 100 times more massive than the gas traced by the higher-excitation observations. This raises the possibility that significant amounts of low-excitation molecular gas may exist in the environments of high-redshift (z > 3) galaxies.

Astronomical Phenomena↗
PubMed2000

Future opportunities for life science programs in space.

Most space-related life science programs are expensive and time-consuming, requiring international cooperation and resources with trans-disciplinary expertise. A comprehensive future program in "life sciences in space" needs, therefore, well-defined research goals and strategies as well as a sound ground-based program. The first half of this review will describe four key aspects such as the environment in space, previous accomplishments in space (primarily focusing on amphibian embryogenesis), available resources, and recent advances in bioinformatics and biotechnology, whose clear understanding is imperative for defining future directions. The second half of this review will focus on a broad range of interdisciplinary research opportunities currently supported by the National Aeronautics and Space Administration (NASA), National Institute of Health (NIH), and National Science Foundation (NSF). By listing numerous research topics such as alterations in a diffusion-limited metabolic process, bone loss and skeletal muscle weakness of astronauts, behavioral and cognitive ability in space, life in extreme environment, etc., we will attempt to suggest future opportunities.

Animals↗
PubMed2003

Pyrolysis experiment of simulated exogenous complex organics synthesized from the gas mixtures of CO, NH3, and H2O by 3 MeV proton irradiation.

High molecular weight organic matter synthesized from mixtures of carbon monoxide, ammonia and water gases similar to those found in the interstellar medium were irradiated with a 3 MeV proton beam and analyzed by Curie point pyrolysis with detection by gas chromatograph and mass spectrometer (Pyr-GC-MS). A wide variety of organic compounds, not only a number of amide compounds, but also heterocyclic and polycyclic aromatic hydrocarbons (PAHs), were detected among the products of the pyrolysis. The present data shows that primary and primitive organic matter serving as precursors to bioorganic compounds such as amino acids, nucleic acid bases and sugar might have been formed in a gaseous mixture of similar composition to that of the interstellar dust environment.

Amides↗
PubMed1979

The analysis of water in the Martian regolith.

One of the scientific objectives of the Viking Mission to Mars was to accomplish an analysis of water in the Martian regolith. The analytical scheme originally envisioned was severely compromised in the latter stages of the Lander instrument package design. Nevertheless, a crude soil water analysis was accomplished. Samples from each of the two widely separated sites yielded roughly 1 to 3% water by weight when heated successively to several temperatures up to 500 degrees C. A significant portion of this water was released in the 200 degrees to 350 degrees C interval indicating the presence of mineral hydrates of relatively low thermal stability, a finding in keeping with the low temperatures generally prevailing on Mars. The presence of a duricrust at one of the Lander sites is taken as possible evidence for the presence of hygroscopic minerals on Mars. The demonstrated presence of atmospheric water vapor and thermodynamic calculations lead to the belief that adsorbed water could provide a relatively favorable environment for endolithic organisms on Mars similar to types recently discovered in the dry antarctic deserts.

Extraterrestrial Environment↗
PubMed2001

Wireless telemetry and Internet technologies for medical management: a Martian analogy.

BACKGROUND: The NASA Haughton-Mars Project Base Camp on Devon Island, Canada (approximately 75 degrees north) was the site for transmission of vital signs from two "terranauts" (individuals who acted as Earthbound astronauts) back to the United States in (artificially delayed) real-time. METHODS: The subjects became "physiologic ciphers" for status monitoring using readily available technologies that affordably captured and distributed vital signs to a variety of platforms. This study of nominal monitoring and simulated medical emergency used wireless technologies and the Internet. RESULTS: Basic vital signs and images can be sent using wireless topologies and completely automated functions. Due to the lightweight transport requirements, existing low data rate connections can easily handle the volume of traffic. CONCLUSIONS: Monitoring, the health of space travelers will be an important component for both low-Earth orbiting spacecraft and long-term missions to distant planets. However, terrestrial applications represent the primary application of such technologies because the home can be a remote and hazardous environment as well.

Aerospace Medicine↗
PubMed1986

Decompression sickness and intravenous bubble formation using a 7.8 psia simulated pressure-suit environment.

The purpose of this study was to determine the minimum spacesuit pressure required to prevent decompression sickness (DCS) during operational conditions in a 50% oxygen/50% nitrogen environment. In this study, 30 male volunteer subjects were exposed in groups of three, to three consecutive daily extravehicular activity (EVA) simulations at 7.8 psia (5,031 m altitude equivalent) for a continuous period of 6 h. During each altitude exposure, the subjects participated in similar exercise workloads expected to be experienced by astronauts during a typical EVA scenario. Precordial Doppler monitoring revealed that 73.3% of the subjects had intravenous bubbling during at least 1 d of the 3 d of exposure, with 26.7% remaining bubble-free during the entire study. No correlation was found between either body fat or age and incidence of bubble formation. One case of DCS occurred during the study indicating that 7.8 psia is not sufficient pressure to totally preclude DCS in a 50% oxygen/50% nitrogen environment. The necessary pressure awaits further study.

Adult↗
PubMed2006

Cryogenic synthesis of molecules of astrobiological interest: catalytic role of cosmic dust analogues.

We have studied the effects of the substrate, namely amorphous olivine (MgFeSiO(4)) cosmic dust analogues (CDAs), in synthesis of molecules obtained after 200 keV proton irradiation of formamide (NH(2)COH). Formamide has been deposited on the olivine substrate at 20 K. The abundances of new molecular species formed after an irradiation dose of 12 eV/16 amu in formamide pure (i.e. deposited on an inert silicon substrate) and deposited on CDAs have been compared. Specifically, MgFeSiO(4) amorphous olivine is a selective catalyst preventing formation of NH(3) and CN(-) molecules and changing the relative abundances of NH4(+)OCN(-), CO(2), HNCO, CO. We have shown that the role of CDAs has to be taken into account in experiments simulating processes occurring in astronomical environments.

Ammonia↗
PubMed1996

Water erosion on Mars and its biologic implications.

The Martian surface shows abundant evidence of water erosion. Liquid water is unstable under present climatic conditions but conditions may have been different in the past. The planet has been volcanically active throughout its history. The combination of water and volcanism must have commonly resulted in hydrothermal environments similar to those in which grow the most primitive terrestrial life-forms.

Atmosphere↗
PubMed1989

Early martian environments: the Antarctic and other terrestrial analogs.

The comparability of the early environments of Mars and Earth, and the biological evolution which occurred on early earth, motivates serious consideration of the possibility of an early martian biota. Environments which could have contained this early martian life and which may presently contain evidence of this former life include aquatic, ice, soil, and rock habitats. Several analogs of these potential early martian environments, which can provide useful information in searching for extinct life on Mars, are currently available for study on Earth. These terrestrial analogs include the perennially ice-covered lakes and sandstone rocks in the Polar Deserts of Antarctica, surface of snowfields and glaciers, desert soils, geothermal springs, and deep subsurface environments.

Antarctic Regions↗
PubMed2000

Sedimentary rocks of early Mars.

Layered and massive outcrops on Mars, some as thick as 4 kilometers, display the geomorphic attributes and stratigraphic relations of sedimentary rock. Repeated beds in some locations imply a dynamic depositional environment during early martian history. Subaerial (such as eolian, impact, and volcaniclastic) and subaqueous processes may have contributed to the formation of the layers. Affinity for impact craters suggests dominance of lacustrine deposition; alternatively, the materials were deposited in a dry, subaerial setting in which atmospheric density, and variations thereof mimic a subaqueous depositional environment. The source regions and transport paths for the materials are not preserved.

Atmosphere↗
PubMed2001

Observational evidence for an active surface reservoir of solid carbon dioxide on Mars.

High-resolution images of the south polar residual cap of Mars acquired in 1999 and 2001 show changes in the configuration of pits, intervening ridges, and isolated mounds. Escarpments have retreated 1 to 3 meters in 1 martian year, changes that are an order of magnitude larger than can be explained by the sublimation of water ice, but close to what is expected for sublimation of carbon dioxide ice. These observations support a 35-year-old conjecture that Mars has a large surface reservoir of solid carbon dioxide. The erosion implies that this reservoir is not in equilibrium with the present environment and that global climate change is occurring on Mars.

Atmosphere↗
PubMed2001

A virtual environment for simulated rat dissection.

Animal dissection for the scientific examination of organ subsystems is a delicate procedure. Performing this procedure under the complex environment of microgravity presents additional challenges because of the limited training opportunities available that can recreate the altered gravity environment. Traditional crew training often occurs several months in advance of experimentation, provides limited realism, and involves complicated logistics. We have developed an interactive virtual environment that can simulate several common tasks performed during animal dissection. In this paper, we describe the imaging modality used to reconstruct the rat in virtual space, provide an overview of the simulation environment and briefly discuss some of the techniques used to manipulate the virtual rat.

Animals↗
PubMed1996

Astrophysical and biological constraints on radiopanspermia.

We have carried out a series of calculations involving bacteria and viruses embedded in dust grains, which are ejected from our solar system by radiation pressure and travel through space to other star systems. Under many conditions this type of panspermia is impractical, primarily because the ultraviolet (UV) radiation of the present Sun inactivates the micro-organisms. However, if the organisms are shielded by an absorbing material like carbon and if ejection takes place in the red-giant phase of a one solar mass star like our Sun, there is a significant probability that the micro-organisms can reach another star system alive (i.e. with only sub-lethal damage from UV and ionizing radiation). In addition to panspermia with viable micro-organisms, it is possible to seed the Galaxy with inactivated ones whose DNA and RNA fragments may provide the initial information necessary to start biological evolution in favourable environments.

Astronomical Phenomena↗
PubMed2001

[Study on induced mutation of sorghum seeds on recoverable satellites].

OBJECTIVE: To observe and investigate the variation and heredity of the offspring of dry seeds of sorghum carried by satellite hence to select excellent mutants and to cultivate directivity new varieties for production application. METHOD: Dry seeds of Tanghui 28, a sorghum restorer line, were carried to the space on board a recoverable satellite for 15 d. After recovery the seeds were planted in the field to study the growth dynamics and change of agricultural characters. RESULT: Variations of characters such as dwarfing of stalk, significant increase grain weight per spike etc were observed in SP1 generation. Wide separation occurred in SP2 generation. Regardless that only non-significant separation of disease resistance and a very little variation of glum color were observed, the other characters varied significantly, and a super large panicle type varied line was obtained. Its spike length was 4 cm longer, and grain weight per spike was 58.5 g more than the control. CONCLUSION: It may be considered that the variation of sorghum seeds induced by the space conditions was heritable to the offsprings. Therefore, exposure to the space environment could be used as a method for mutagenic seeds breeding.

Edible Grain↗