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2003 Annual Science Report

NASA Jet Propulsion Laboratory Reporting  |  JUL 2002 – JUN 2003

Executive Summary

The fifth year of the JPL/Caltech/USGS NAI group was a great success with regard to discovery, publication of seminal work, representation of the work to the public, and overall adherence to the roadmap objectives espoused by the NAI. The work was highlighted by several keynote publications in the areas of life detection and biosignature development and testing, and set the stage for future work in the area: work critical to the assessment and testing of instruments for life detection missions. Each Co-I trained several students and postdocs, presented papers at the NAI annual meeting, and many of them presented plenary lectures at national and international meetings. Some of these are highlighted below.

As has been stated previously, the goal of our program slowly evolved from that of the co-evolution of Earth and its life, to that of a goal focused more centrally on the definition of life, the development of methods for its detection, the testing of some of these methods, and the beginnings of moving these methods to mission readiness.

The Co-Is of the program in the last year included:

  • G. Blake and Y. Yung, Caltech — Isotopes of nitrogen oxides as biosignatures
  • J. Kirschvink, Caltech — Microbial magnetosomes as biosignatures
  • T. Ahrens, Caltech — The effect of impact on potential biosignatures
  • G. McDonald, JPL — Organic geochemical biosignatures
  • M. Fogel and D. Rumble, CIW — Stable isotopes of C and S as biosignatures
  • C. Johnson, Univ. of Wisconsin — Stable isotopes of Fe as biosignatures
  • J. Banfield, UC Berkeley — Mineral weathering as a biosignature
  • A. Anbar, U. Rochester — Stable isotopes of metals as biosignatures
  • K. Nealson, JPL/USC — Development of strategies for life detection

For each of these areas, significant progress was made, papers were published in major journals, as noted in the individual reports, and national and international presentations were made. Some of these are highlighted below:

Of particular note, and delineated in the individual progress reports, was the work of Dr. J. Kirschvink, who has been a proponent of microbial magnetosomes as biosignatures. His work on magnetosomes produced a number of published papers, generated great interest in this area, and continues to be interpreted as a potential biosignature both in subsurface samples on Earth, and in extraterrestrial samples, when returned. This work involved collaboration and interactions with members of the NAI from several centers, and within our own group.

In addition, Dr. Clark Johnson has continued his work with stable isotopes of iron, one of the areas that represents one of the seminal discoveries of our NAI program, and one that has attracted major attention in the international arena.

Dr. Gene McDonald of the JPL made considerable progress using amino acids as biosignatures to study several different earthly sites, and developed several approaches for applying these methods to extraterrestrial samples. In addition, in collaboration with members of the CIW group, analyzed tholin compounds with the goal of modeling their production and properties for the upcoming Cassini mission.

Members of our team have been involved with a number of NASA groups including the roadmap writing exercise, Mars Exploration Assessment Group (MEPAG), as well as with several ongoing missions, including Mars Global Surveyor, Odyssey (Nealson is a Co-I on Thermal Emission Imaging System (THEMIS)), and have participated in the writing of several new proposals for missions.

Finally, members of the JPL-1 team have been outstanding in terms of public interactions, presenting major talks at many meetings, both national and international. These include plenary lectures at several conferences, many lead talks at Gordon Conferences, and talks at international meetings. These talks have ranged from general talks about life detection strategy to very specific talks involving individual biosignatures being studied by each PI.