2000 Annual Science Report

NASA Johnson Space Center Reporting  |  JUL 1999 – JUN 2000

Executive Summary

There is no executive summary for this team at this time.

Field Sites
19 Institutions
3 Project Reports
0 Publications
0 Field Sites

Project Reports

  • Biosignatures in Extraterrestrial Samples

    This project concentrates on studying the martian meteorites in our systematic search for biosignatures in extraterrestrial samples. The research by JSC and Co-Investigator scientists currently includes four major biological / organic investigations, analysis of magnetite crystals, analysis of features morphologically similar to fossilized terrestrial organisms, detection of trace-level organic compounds, and assessment of terrestrial microbial contamination.

    In addition, we are conducting ongoing studies of chemical weathering on Mars and on Earth, and analyzing experimental shock effects to document the possibility of biomarker preservation in meteoritic materials. Finally, we have proposed to broaden the Astrobiology investigation of these unique extraterrestrial samples through a new Inter-Institute Focus Group on Martian Meteorites.

  • Biomarkers in Terrestrial Samples

    The importance of terrestrial samples to Astrobiology cannot be overestimated. Only by understanding the evidence for life preserved in the rocks and soil of Earth can we assess indications of possible life elsewhere in the universe. We currently have four main thrusts of this research: Modern Life in Extreme Environments, Ancient Life, Natural contamination of fossiliferous and non-fossiliferous lithologies, and Experiments.

    Modern Life in Extreme Environments

    We are studying samples from hot springs, caves, mines and endolithic environments to document the presence of microbial life and its physical and chemical biomarkers.

    Ancient Life
    We are studying rocks that contain the earliest physical evidence of life on Earth, in order to document the retention of microbial forms and other biosignatures in the geologic record. Furthermore, we are investigating the variety of environments in which the most ancient life is preserved. This will hopefully aid interpretation of where and possibly how life started.

    Natural contamination of fossiliferous and non-fossiliferous lithologies
    Fossiliferous rocks can become naturally contaminated through microbes living in cracks in both fossiliferous and non-fossiliferous lithologies, as well as microbes living between grains in harsh environments. We are looking at fossilized microbes in cracks in Early Archaean, carbonaceous, fossiliferous cherts, as well as in serpentinized deep sea ultramafics. Fossilized endolithic microorganisms in Arctic environments are also being investigated. Impact craters comprise another environment under investigation for fossilized endolithic organisms.

    We are conducting irradiation and shock experiments on terrestrial rocks to understand the effects of these stresses on samples from other planets. Some of the material being shocked is fossiliferous. Fossiliferous Early Archaean cherts are being experimentally metamorphosed to determine the effects of amphibolite/lower granulite metamorphism on the survival of carbonaceous microfossils. Films formed from prebiotic molecules are being artificially created as a comparison for biogenic films (biofilms) in order to distinguish differences between abiotic and biotic polymer films.

    ROADMAP OBJECTIVES: 6.0 7.0 17.0
  • Biomarkers Database

    The JSC Astrobiology group’s main goal is to develop, characterize, and document a set of reliable biomarkers that can be used to identify present or past forms of microbial life. The research efforts of many groups are being consolidated in a continuously-updated electronic database.