There are a lot of questions here about looking for life on Mars, potentially finding life on Mars, how to deal with life on Mars as far as contamination one way or the other, even whether or not sending people could help in the search for life. But I wonder how finding life would affect any plans to send people.
If a rover were to find life on Mars, would that prompt space agencies to accelerate their goals to get humans to Mars, slow down any potential plans, or would it have no effect? For instance, let's say life is found tomorrow, does NASA have anything that says "any talks of plans to send people to Mars are suspended"?

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    $\begingroup$ It would affect it greatly. However it is not clear if that would speed things up greatly due to our curiosity, or slow things down greatly due to our desire to not impact the Martian biosphere. Let's hope we get to see this experiment played out. $\endgroup$
    – Mark Adler
    Aug 6, 2015 at 4:14
  • $\begingroup$ Worth pointing out, there are no plans to send people to mars, just talk so far. Nobody knows when it's likely to be done but talk wouldn't stop. As pointed out, a discovery of life would significantly increase our interest, so that would speed things up, but it would also significantly increase our caution and that could delay a human landing. A precise answer is impossible, but it's worth noting, Mars doesn't really have a "biosphere", it has no atmosphere and no liquid water, so any life would likely have to be well underground or frozen in ice and not very vulnerable to our landing. $\endgroup$
    – userLTK
    Aug 8, 2015 at 13:46

2 Answers 2


The Outer Space Treaty (signed by the US in 1967) specifies that (Article IX):

States Parties to the Treaty shall pursue studies of outer space, including the Moon and other celestial bodies, and conduct exploration of them so as to avoid their harmful contamination and also adverse changes in the environment of the Earth resulting from the introduction of extraterrestrial matter and, where necessary, shall adopt appropriate measures for this purpose.


If a State Party to the Treaty has reason to believe that an activity or experiment planned by it or its nationals in outer space, including the Moon and other celestial bodies, would cause potentially harmful interference with activities of other States Parties in the peaceful exploration and use of outer space, including the Moon and other celestial bodies, it shall undertake appropriate international consultations before proceeding with any such activity or experiment.

Note the "activity or experiment planned by it or its nationals in outer space": that means SpaceX or other private companies can't just ignore the treaty because they aren't a state. It does leave a lot open (restricts "harmful contamination", not all contamination, etc), but the second snippet appears to be the basis for COSPAR.

While it's not binding (they "develop recommendations") COSPAR has a list of guidelines for avoiding interplanetary contamination. Of particular interest for Mars:

  • Category IVa. Landers that do not search for Martian life - uses the Viking lander pre-sterilization requirements, 300,000 spores per spacecraft and 300 spores per square meter.
  • Category IVb. Landers that search for Martian life. Adds stringent extra requirements to prevent contamination of samples.
  • Category IVc. Any component that accesses a Martian special region must be sterilized to at least to the Viking post-sterilization biological burden levels (30 spores total per spacecraft).

I would interpret that to mean that if life were detected, especially in a "Martian special region" there are no guidelines that would prevent a manned mission from landing outside the special regions, especially if the intent of the manned mission wasn't to search for life. That leaves NASA without a rule that would mean "any talks of plans to send people to Mars are suspended".

On the other hand, the possibility of life would most likely focus research money (and political will/public opinion) on attempting confirmation, and depending on the approach taken it could either help or hinder manned activities:

  1. Focus on a sample return mission would almost certainly rule out a manned lander: sterilizing the spacecraft to "30 spores total per spacecraft" (per Category IVc from above) doesn't sound friendly to any astronauts aboard. Sample return would certainly have timeline issues (from here).

    • The National Environmental Policy Act (NEPA) would likely require a formal environment impact statement, including public hearings during which all the issues would be aired openly. Wikipedia suggests that the process could take years to complete. This is in sharp contrast to the Apollo 11 quarantine regulations, which were announced the day of launch, preventing any public discussion from taking place.
    • NASA has proposed a Mars Sample Return Receiving facility (MSRRF), but the timeline speculation on the wikipedia page estimates 7-10 years to build it and an additional 2 years to get the staff accustomed to the facility to reduce risk of accidents.
  2. In-situ research could be aided by astronauts in orbit controlling rovers via telepresence. The astronauts wouldn't be going to the surface and the rovers could be sterilized and launched separately to minimize the risk of contamination, but having astronauts orbiting Mars would reduce the latency such that they could directly control rovers doing analysis or even collecting material to return to orbit for further analysis. This would allow volatiles to be analyzed without the delay of return to Earth allowing them to break down.

It's impossible to say for sure at this point (and my two options didn't even touch on in-situ research not aided by astronauts, which is what all the existing rovers/landers have done), but given a fresh (and abundant) source of funding NASA might go with option 2 for the purpose of being first with manned flight to Mars (which is already planned, just not this exact mission).

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    $\begingroup$ I think you have a naive overconfidence in "treaties". When anything happens which would activate any of these treaties, they will immediately be ignored and revised. They always have. Or what is the oldest treaty you can find which has not been violated by government? $\endgroup$
    – LocalFluff
    Aug 6, 2015 at 14:31
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    $\begingroup$ Agreed. The treaty has lasted this long only because there's been no incentive to violate it. We're likely in the fading days of it. $\endgroup$ Feb 15, 2018 at 3:28

If life is found on Mars, NASA does not have anything that would suspend travel to Mars.

However, NASA does have a NPD: Biological Contamination Control for Outbound and Inbound Planetary Spacecraft , and would also have to comply with the NEPA process. (They have to do these either way, but knowing there was life would ensure increased scrutiny)

Section 102 requires NASA to incorporate environmental considerations in their planning and decision-making through a systematic interdisciplinary approach leading to a detailed assessment, called an environmental impact statement (EIS), of the environmental impact of and alternatives to NASA actions significantly affecting the environment. Section 102 also requires NASA to lend appropriate support to initiatives and programs designed to anticipate and prevent a decline in the quality of mankind's world environment.

Discovery of life on Mars, would likely result in an accelerated timeline, of the missions already proposed, eventually leading to humans on Mars, in a slightly shorter time frame. (At a minimum, it would result in a higher likelihood, the existing strategy is not derailed.)

First and foremost, it would lead to greater public support for additional flights to Mars. This support would likely lead to increased funding, and more focused political will. Additional funding, and additional political will, would result in shorter time spans for existing martian missions, most notably the Mars sample return mission. The sooner humanity can practice and prove safe harbor of potential contaminates from another planet (without humans), the sooner the necessary approvals for allowing humans to return to earth would be completed.

While this process would be long, even after such an amazing discovery, I believe, it would be shorter then the current plan, which is still decades away.

NASA is developing the capabilities needed to send humans to an asteroid by 2025 and Mars in the 2030s

  • $\begingroup$ What has NEPA got to do with Mars? Did you mean NASA Policy Directive (NPD) 8020.7G: Biological Contamination Control for Outbound and Inbound Planetary Spacecraft? $\endgroup$
    – TildalWave
    Aug 6, 2015 at 3:41
  • $\begingroup$ @TidalWave Mars Sample Return Discussions February 23, 2010 *Mars Sample Return is conceptual in nature and is subject to NASA approval. This approval would not be granted until NASA completes the National Environmental Policy Act (NEPA) process. -- NEPA applies to anything that came in contact with the martian life upon their arrival back at Earth. P.S. The NPD would also apply, good catch. $\endgroup$ Aug 6, 2015 at 4:06
  • $\begingroup$ NEPA only provides a baseline for backward contamination. While it is a requirement, it doesn't specifically apply only to human missions (as you've mentioned), but it doesn't cover the complete spectra of the planetary protection and doesn't even care about forward contamination (OST does however), which, I'd argue, would be a far more pressing issue if life on Mars was discovered. We'd most certainly want to know a great deal more about it before sending humans there, so it would most likely substantially delay that in favor of many more robotic missions to reduce knowledge gap. $\endgroup$
    – TildalWave
    Aug 6, 2015 at 4:19
  • $\begingroup$ @TidalWave Good point, I have added a reference to the NPD to my answer. I believe NASA's current plan, which involves robot missions first, robotic sample returns second, and humans third, already optimistically, includes heavy amounts of protection against cross contamination of life (even though none has been discovered). With this in mind, I believe the same strategy would be followed if life was actually discovered, just on a slightly decreased timeline due to greater public/political/financial support. $\endgroup$ Aug 6, 2015 at 4:33
  • $\begingroup$ The Apollo/Mercury program is evidence of what the right amount of money, and the right amount of political will, can accomplish. Mars would be no exception. $\endgroup$ Aug 6, 2015 at 4:52

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