Good astrobiology papers

A few months ago I asked for examples of good astrobiology papers, but the response was disappointing.  This prompted me to suggest a discussion at Science Foo Camp titled "Astrobiology: Buzzword or Science". 

Sarah Kendrew, one of the participants in this discussion, has now posted a thoughtful follow-up on her One Small Step blog: Astrobiology-where's-the-bacon?.  She points to good work on identifying planets that could support Earth-like life, and discusses the need for more collaboration between astronomers and biologists.

Enceladus photo from NASA

The astrobiology discussion at SciFoo was fruitfully combined with a discussion on the ethics of planetary exploration, posed by Jill Tarter, titled "What if Mars has Martians?".  This was something I hadn't given much thought to.  The big issue at present is the possibilities of contamination of other systems with organisms from Earth, and of Earth with hypothetical organisms from other systems.  The consensus was that 'certainty' is a better word than 'possibility', at least where contamination originating on Earth is concerned.  This applies not only to manned exploration but to unmanned visits too, but nobody was quite ready to say that these should all be stopped.

In addition to the above discussion, Jill and other participants were able to provide some history of NASA's Astrobiology program.  I and others had wondered if this was initiated mainly as a public relations exercise, but it was a real grass-roots initiative by NASA scientists.