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Executive Summary

Executive Summary — JPL2
Astronomical Detection of Biosignatures From Extrasolar Planets (dm)

Motivated by the recent discoveries of a multitude of extrasolar planets, NASA has initiated a series of studies for space-based observatories that will be able to search for life on these worlds. To optimize the designs of these NASA missions, and to ultimately interpret the data that they return, we need to be able to recognize habitable worlds and to discriminate between planets with and without life.

The principal goal of this research is to learn how to recognize the presence of life on extrasolar planets by identifying the signatures of life in their spectra. To achieve this goal, we are developing a suite of innovative modeling tools to simulate the environments and spectra of extrasolar planets. The modeling tools will constitute a Virtual Planetary Laboratory, which will be used to explore the plausible range of atmospheric compositions and globally-averaged spectra for early Earth, other planets in our solar
system, and for extrasolar planets both with and without life. The results of this research will provide an improved understanding of the range of atmospheric compositions that are possible for planets with and
without life, and will help to quantify the effect of life on the atmospheric spectrum and composition of a planet. The models will also provide a comprehensive spectral catalog, a “menu” of biosignatures,
which will be used to determine the optimum wavelength range, spectral resolution, and sensitivity required to remotely sense the signs of life in the atmosphere or on the surface of another world. This study will also provide recommendations for the design and optimization of the search strategies for future NASA planet detecting and characterizing missions such as TPF and Life Finder.