If there's life on Mars right now, it's either really good at hiding from our robots, or it's too small to be able to wave at us. In either case, an effective way of finding it might be through gene sequencing, which is why scientists want to send a DNA sequencer on Mars. It's called "the search for extraterrestrial genomes," which I have abbreviated to "SEx GNomes."
MIT has been working on a SEx GNomes project (the real abbreviation is apparently "SETG" but that's boring) for years now, but the big new news is that two high-profile and pretty darn rich venture biologists, J. Craig Venter and Jonathan Rothberg, are each working on sending a robotic gene machine to Mars.
J. Craig Venter, one of the first people to sequence the human genome, has already begun testing an instrument in the Mojave desert in New Mexico that will (eventually) be able to autonomously isolate microbes from Martian soil, sequence up all of their DNA, and then send the results straight back to Earth. The instrument is not 100% robotic quite yet, but Venter's company, Synthetic Genomics, is working on it.
Meanwhile, Jonathan Rothberg and his company Ion Torrent already make a personal DNA sequencer called, uh, Ion Torrent, and they want to send it to Mars, too. Ion Torrent is already a part of the
SEx GNomes SETG project and has NASA backing as well. The Ion team is working to shrink the entire machine down to just three kilograms, giving it a shot at a berth on the next Mars rover, which could launch as early as 2018.
Neither of these machines is designed to detect past life on Mars: if they find anything through DNA sequencing, it's going to be because something is alive there now. It may not be likely, but it's one of those exciting high-risk, high-payoff missions that, if successful, would have enormous implications for life elsewhere in the Universe.
And what happens if or when some robot on Mars manages to sequence an alien genome? Here's one idea:
Venter also said it might be feasible in the future to reconstruct Martian organisms in a super-secure laboratory on Earth, using just their DNA sequence. The idea would be to use the DNA data to rebuild their genomes and then inject those into an artificial cell of some kind. It's an idea he calls the "biological teleporter."
Nothing could possibly go wrong.