The search for life on Mars: What we learned from Viking

Klein, Harold P.

doi:10.1029/98je01722

Cited by 44 publications

(27 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Pathfinder technology built on the Viking heritage but did not specifically contain exobiological instrumentation. In his review of what we learned from Viking, Klein (1998) concluded that the location of any near-surface life on Mars will be in cryptic special environmental niches. These might include sedimentary layers containing cyanobacteria (formerly classified as blue-green algae) preserved as stromatolites (Wharton et al 1995), endolithic communities inside rocks (Friedmann 1982), or evaporite salt pans (Rothschild 1990).…”

Section: Introductionmentioning

confidence: 98%

Proximal Analysis of Regolith Habitats and Protective Biomolecules in Situ by Laser Raman Spectroscopy: Overview of Terrestrial Antarctic Habitats and Mars Analogs

Wynn‐Williams

Edwards

2000

Icarus

202

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 98%

Proximal Analysis of Regolith Habitats and Protective Biomolecules in Situ by Laser Raman Spectroscopy: Overview of Terrestrial Antarctic Habitats and Mars Analogs

Wynn‐Williams

Edwards

2000

Icarus

202

View full text Add to dashboard Cite

“…If microorganisms exist on Mars, they have adapted to much colder and direr conditions than are common on Earth [Klein, 1998]. Such conditions are apparently correlated with high resistance to ionizing radiation.…”

mentioning

confidence: 99%

“…The return of documented samples, carefully collected and preserved, will be a major step in the search for evidence of Martian life. Martian conditions, including the lack of organic matehal, subfreezing temperatures, high flux of solar ultraviolet radiation, and strongly oxidizing chemical species in the soil, severely limit the survival of organisms at or near the surface [Klein, 1998] inCenters for Disease Control and Prevention, Atlanta, Georgia.•University of Portsmouth, Portsmouth, England.Copyright 1999 by the American Geophysical Union. …”

mentioning

confidence: 99%

Effects of sterilizing doses of gamma radiation on Mars analog rocks and minerals

Allen¹,

Albert²,

Combie³

et al. 1999

J. Geophys. Res.

View full text Add to dashboard Cite

Abstract. Rock and soil samples from the planet Mars are due to be returned to Earth within a decade. Martian samples initially will be tested for evidence of life and biological hazard under strict biological containment. Wider distribution of samples for organic and inorganic analysis may occur only if neither evidence of life nor hazard is detected, or if the samples are first sterilized. We subjected a range of Mars analog rocks and minerals to high doses of gamma radiation in order to determine the effects of gamma sterilization on the samples' isotopic, chemical, and physical properties. Gamma photons from 6øCo (1.17 and 1.33 MeV) in doses as high as 3 x 107 rads did not induce radioactivity in the samples and produced no measurable changes in their isotopic and chemical compositions. This level of irradiation also produced no measurable changes in the crystallographic structure of any sample, the surface areas of soil analogs, or the fluid inclusion homogenization temperature of quartz. The only detectable effects of irradiation were dose-dependent changes in the visible and near-infrared spectral region (e.g., discoloration and darkening of quartz and halite and an increase in albedo of carbonates) and increases in the thermoluminescence of quartz and plagioclase. If samples returned from Mars require biological sterilization, gamma irradiation provides a feasible option. BackgroundMartian rock and soil, collected by robotic spacecraft, will be returned to terrestrial laboratories early in the next century. The return of documented samples, carefully collected and preserved, will be a major step in the search for evidence of Martian life. Martian conditions, including the lack of organic matehal, subfreezing temperatures, high flux of solar ultraviolet radiation, and strongly oxidizing chemical species in the soil, severely limit the survival of organisms at or near the surface [Klein, 1998] inCenters for Disease Control and Prevention, Atlanta, Georgia.•University of Portsmouth, Portsmouth, England.Copyright 1999 by the American Geophysical Union. Paper number 1999JE001064.0148-0227/99/1999JE001064509.00 specialized organisms at low concentrations in the returned samples is conceivable [Clark, 1998].Current planetary protection strategies call for the samples to be immediately placed into biological containment and tested for signs of present or past life and biological hazard [DeVincenzi et al., 1998]. It is recommended that "Controlled distribution of unsterilized materials from Mars should occur only if rigorous analyses determine that the materials do not constitute a biological hazard. If any portion of the sample is removed from containment prior to completion of these analyses it should first be sterilized" [Space Studies Board, 1997]. While sterilization of Mars samples may not be required, an acceptable method must be available before the samples are returned to Earth.A variety of sterilization techniques have been used or proposed for spacecraft missions to Mars. These include dry heating to t...

show abstract

“…However, our knowledge of the light elements (particularly C and H, the most fundamental constituents of life) is still very limited. The Viking lander experiments looked for carbon in soils, but found nothing at the 1 ppb sensitivity level provided by those instruments (Klein, 1998). This was the case, despite the expectation that carbon-bearing compounds should be present from the constant rain of interplanetary dust particles and organicrich meteorites being delivered to the martian surface.…”

Section: C2 Were Habitable Environments Present On Earlymentioning

confidence: 90%

Key Science Questions from the Second Conference on Early Mars: Geologic, Hydrologic, and Climatic Evolution and the Implications for Life

et al. 2005

View full text Add to dashboard Cite

In October 2004, more than 130 terrestrial and planetary scientists met in Jackson Hole, WY, to discuss early Mars. The first billion years of martian geologic history is of particular interest because it is a period during which the planet was most active, after which a less dynamic period ensued that extends to the present day. The early activity left a fascinating geological record, which we are only beginning to unravel through direct observation and modeling. In considering this time period, questions outnumber answers, and one of the purposes of the meeting was to gather some of the best experts in the field to consider the current state of knowledge, ascertain which questions remain to be addressed, and identify the most promising approaches to addressing those questions. The purpose of this report is to document that discussion. Throughout the planet's first billion years, planetary-scale processes•including differentiation, hydrodynamic escape, volcanism, large impacts, erosion, and sedimentation•rapidly modified the atmosphere and crust. How did these processes operate, and what were their rates and interdependencies? The early environment was also characterized by both abundant liquid water and plentiful sources of energy, two of the most important conditions considered necessary for the origin of life. Where and when did the most habitable environments occur? Did life actually occupy them, and if so, has life persisted on Mars to the present? Our understanding of early Mars is critical to understanding how the planet we see today came to be.

show abstract

The search for life on Mars: What we learned from Viking

Cited by 44 publications

References 27 publications

Proximal Analysis of Regolith Habitats and Protective Biomolecules in Situ by Laser Raman Spectroscopy: Overview of Terrestrial Antarctic Habitats and Mars Analogs

Proximal Analysis of Regolith Habitats and Protective Biomolecules in Situ by Laser Raman Spectroscopy: Overview of Terrestrial Antarctic Habitats and Mars Analogs

Effects of sterilizing doses of gamma radiation on Mars analog rocks and minerals

Key Science Questions from the Second Conference on Early Mars: Geologic, Hydrologic, and Climatic Evolution and the Implications for Life

Contact Info

Product

Resources

About