While working on something else, I was listening to the following SETI talk about looking for life at Martian hydrothermal vents, especially at the Nili Patera. The talk is interesting, but sparked a thought related back to another, previous SETI talk.
The previous seti talk was about planetary protection or the idea we ought to prevent earth life from spreading to other bodies in the solar system so we can both study the worlds before life changes them, and be able to verify life does not (or does) exist before we contaminate the environment, so to speak, making it difficult to know what is happening.
There is a huge push for planetary protection now given the push to putting people on Mars. There has even been suggestions people, given how biologically active we are, should not land on Mars at all! That might not be given much serious consideration, but the level of protection has significant impacts on costs of missions and will have a serious impact on costs for any human space flight missions to Mars.
All of the assumptions about hinges on the suggestion Earth life can survive on Mars. Everything done to date about whether or not microbial or other life could survive on Mars has been either done in a lab or purely theoretical. The labs really first order approximations of the environment on Mars, and a good first step in studying the potential for survival and contamination. The rest is purely speculative or theoretical. It need not be.
I am not suggesting sending life to another world. While I think that will be an ultimate goal, I am thinking, here, that some ground truth ought to be established for planetary protection efforts. To that end, we have five potential sites on Mars where there may be biological contamination. Those sites are the Viking lander sites and the original Soviet Mars landers (Mars-2, Mars-3 & Mars-6). None of these earlier missions were biologically protected to the levels of modern missions and may have caused contamination.
Before we wrap ourselves up in impossible requirements for planetary protection, it would make an enormous amount of sense to send specific missions to Mars to check for contamination at the Viking and Soviet Mars sites. Perhaps one from each mission series, one American and one Soviet. That would give us some 'ground truth' about the need for biological protection. It would also establish if Mars is already irrevocably contaminated already or if Earth life cannot establish a toe hold on Mars without Human help.
I would suggest these be a couple rovers with TBD instruments and they be paid for through the Exploration line item rather than the Mars program or discovery, etc. This would prevent the mission from raiding other portions of the NASA budget. It would also scope expectations for the level of protection necessary for planetary missions. That in turn impacts their costs.
Something to consider.