Strategies of Life Detection

J. L. Bada·J. Gomez-Elvira·E. Javaux·M. Rosing· F. Selsis·R. Summons·R. M. Bonnet·O. Botta Originally published in the journal Space Science Reviews, Volume 135, Nos 1¿4. DOI: 10. 1007/s11214-008-9328-1 © Springer Science+Business Media B. V. 2008 Twooftheoverarchingquestionsaskedinthepursuitofscienti c knowledgeare:(1)Isthere life outside the Earth? and (2) How did life originate on the Earth? Not coincidently, these questions are major milestones on the roadmap of the new interdisciplinary science eld of Astrobiology. A signi cant part in the quest for answers to these questions requires the involvement of space exploration, either in the form of the deployment of planetary probes to various target objects in the Solar System or of the construction of large telescopes and spectrometers in various orbits around the Earth or the Sun. It does not come as a surprise that space agencies such as NASA or ESA have established programs in support of these missions as well as the development of instruments. In the case of planetary probes, which in the current epoch are mainly focusing on the exploration of Mars, but also include missions to asteroids and comets, the development of in-situ instruments to search for traces of past J. L. Bada Scripps Institution of Oceanography, UCSD, La Jolla, CA, USA J. Gomez-Elvira Centro de Astrobiología (INTA-CSIC), Madrid, Spain E. Javaux University of Liège, Liège, Belgium M. Rosing Geological Museum Copenhagen, Copenhagen, Denmark F. Selsis University of Lyon, Lyon, France R. Summons Massachusetts Institute of Technology (MIT), Cambridge, MA, USA R. M. Bonnet· O.