Well, first, Curiosity can't drill more than a few mms. And I think from the report that they believe the signal probably comes from outside Gale crater. So - most it can do is to continue to detect these methane signals, and maybe give more evidence about the geographic origin of them, from wind directions etc.
The next step is ExoMars, so by ESA not NASA. If they keep to their target they should land ExoMars in 2019.
This is significant because it is the first rover to be sent to Mars with the ability to search for life directly in situ.
NASA are following a different process. They are not sending any life detection equipment to Mars. Just detection of organics. So - unlikely to conclusively verify life on Mars.
They plan to return a sample to Earth some time in the 2020s. But there are many safety and regulatory issues involved in this. If there is life on Mars then what it is returning what could, in most interesting but hardest to contain case - be life based on XNA and smaller in physical size than any Earth based microbes. It is not entirely clear, I think, that we have the technology to contain such, in face of possiblities of natural disasters, criminal action or indeed oversight and carelessness of the operators of the facility. The microbes involved could indeed quite easily be sub-optical resolution, only visible in an electron microscope.
And as well as that - it is entirely possible that most organics on present day life is either severely degraded by cosmic radiation, or else delivered by comets. It might be necessary to drill to find good evidence of life, and also conditions may be rare on Mars for preservation of life from the past. And as for present day life, then due to the extreme aridity and desert conditions, the most habitable regions of Mars are probably no more habitable than the very centre of the Atacama desert where in some cases no rainfall has ever been recorded in recent history. There has never been any rainfall on Mars for millions of years.
So again there may be present day life on Mars, but hard to find. NASA aren't at present pursuing strategies likely to conclusively find either present or past life, I think many would say.
Of course that may change and they may introduce new mission ideas on the basis of new findings. E.g. if ExoMars finds life using in situ exploration and life detection - either present day or past life - I think that might possibly spur NASA on to add in situ life detection to its missions also. Which they haven't done since Viking.
Similarly if ExoMars finds past life by drilling for it, then perhaps NASA might follow up that approach also with future rovers and we might get rovers capable of drilling to greater and greater depths. We have the technology to do this in theory, to drill even hundreds of meters, even kilometers - that could be done in future rovers if there was the interest in doing so. Perhaps if this methane does come from deep underground it might be a spur for this.
And BTW you don't need humans for deep drilling on Mars. I think, not even clear that they would help with their clumsy spacesuits and this environment where you can't lubricate drill bits. While of course introducing risk of contamination by Earth microbes. The most promising approach seems to be to use automated "moles" on Mars that "burrow through the ground" leaving a cable behind to communicate with the surface.
Also - BTW again there could be several different species and habitats for life on Mars. So - these methanogens, if it is indeed life based methane - they may not be the only life forms on Mars. For instance there could be other life forms that produce oxygen and CO2 as biproducts.
And - if the life is thinly spread on the surface, similarly to the life in the centre of the Atacama desert, and only in the most habitable regions of Mars, it could easily have no detectable effect on the atmosphere at all within the resolution of Curiosity.
So - some news reports suggest, almost, that this is the "only hope" for life on Mars. Far from it. If this is life originated, it would suggest a huge population of methanogens on Mars. But if it is not life originated, if we find a geological source for this methane - you can't conclude anything either way about presence of life there.
There may easily still be many other lifeforms on Mars, including indeed methanogens but in smaller "desert like" populations. Also, lifeforms in habitats not physically connected to the surface. And lifeforms with other biological biproducts such as oxygen instead of methane.
So I think that's worth thinking about.
To quote myself :)
See Where To Search On Mars For Droplets, & Shallow Flows Of Liquid Water - Where Microbial Life May Flourish
The next step is ExoMars, so by ESA not NASA. If they keep to their target they should land ExoMars in 2019.
This is significant because it is the first rover to be sent to Mars with the ability to search for life directly in situ.
NASA are following a different process. They are not sending any life detection equipment to Mars. Just detection of organics. So - unlikely to conclusively verify life on Mars.
They plan to return a sample to Earth some time in the 2020s. But there are many safety and regulatory issues involved in this. If there is life on Mars then what it is returning what could, in most interesting but hardest to contain case - be life based on XNA and smaller in physical size than any Earth based microbes. It is not entirely clear, I think, that we have the technology to contain such, in face of possiblities of natural disasters, criminal action or indeed oversight and carelessness of the operators of the facility. The microbes involved could indeed quite easily be sub-optical resolution, only visible in an electron microscope.
And as well as that - it is entirely possible that most organics on present day life is either severely degraded by cosmic radiation, or else delivered by comets. It might be necessary to drill to find good evidence of life, and also conditions may be rare on Mars for preservation of life from the past. And as for present day life, then due to the extreme aridity and desert conditions, the most habitable regions of Mars are probably no more habitable than the very centre of the Atacama desert where in some cases no rainfall has ever been recorded in recent history. There has never been any rainfall on Mars for millions of years.
So again there may be present day life on Mars, but hard to find. NASA aren't at present pursuing strategies likely to conclusively find either present or past life, I think many would say.
Of course that may change and they may introduce new mission ideas on the basis of new findings. E.g. if ExoMars finds life using in situ exploration and life detection - either present day or past life - I think that might possibly spur NASA on to add in situ life detection to its missions also. Which they haven't done since Viking.
Similarly if ExoMars finds past life by drilling for it, then perhaps NASA might follow up that approach also with future rovers and we might get rovers capable of drilling to greater and greater depths. We have the technology to do this in theory, to drill even hundreds of meters, even kilometers - that could be done in future rovers if there was the interest in doing so. Perhaps if this methane does come from deep underground it might be a spur for this.
And BTW you don't need humans for deep drilling on Mars. I think, not even clear that they would help with their clumsy spacesuits and this environment where you can't lubricate drill bits. While of course introducing risk of contamination by Earth microbes. The most promising approach seems to be to use automated "moles" on Mars that "burrow through the ground" leaving a cable behind to communicate with the surface.
Also - BTW again there could be several different species and habitats for life on Mars. So - these methanogens, if it is indeed life based methane - they may not be the only life forms on Mars. For instance there could be other life forms that produce oxygen and CO2 as biproducts.
And - if the life is thinly spread on the surface, similarly to the life in the centre of the Atacama desert, and only in the most habitable regions of Mars, it could easily have no detectable effect on the atmosphere at all within the resolution of Curiosity.
So - some news reports suggest, almost, that this is the "only hope" for life on Mars. Far from it. If this is life originated, it would suggest a huge population of methanogens on Mars. But if it is not life originated, if we find a geological source for this methane - you can't conclude anything either way about presence of life there.
There may easily still be many other lifeforms on Mars, including indeed methanogens but in smaller "desert like" populations. Also, lifeforms in habitats not physically connected to the surface. And lifeforms with other biological biproducts such as oxygen instead of methane.
So I think that's worth thinking about.
To quote myself :)
With the rarer types of habitat here, there may be no more than a few square kilometers of habitat over entire surface of Mars, for a few hours a year.
If it was all photosynthetic life, and as active as life in the ice covered ponds of the McMurdo Dry Valleys of Antarctica, the oxygen produced would contribute at most a few hundred kilograms of gases per surface square kilometer of habitat.
So, if the entire surface of Mars is habitat (which surely it isn't), that contributes less than 0.0002% of the Mars atmosphere if left to build up over a "residence time" of 4,500 years. That compares to a measured 0.145% of oxygen in the atmosphere - so any seasonal effect is likely to be hidden in the noise. For the calculation, see my How Life May Exist On Mars With Atmosphere Close To Equilibrium.
See Where To Search On Mars For Droplets, & Shallow Flows Of Liquid Water - Where Microbial Life May Flourish
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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