First probably, the ESA Juice, in the early 2020s. It ends up in orbit around Ganymede (first mission to orbit another moon in the solar system) but on the way, as well as studying Jupiter and Callisto, it does a couple of flybys of Europa to make measurements to find size of its internal oceans and to help select a site for in situ exploration later.
ESA selects instruments for JUICE mission to explore Jupiter and its moons
Then there's the NASA Europa Clipper - to do flybys of Europa again, hopefully to sample water plumes ejected from Europa and analyse it. But this is a proposal. In the last decadal review they dropped it in favour of a Mars sample return. They might do the same in the next decadal review, as the sample return is a two decade project, and a Europa Clipper is a major expenditure, or they might trim it down as far as they can.
Though I think Mars is well deserving of more study for search for life, I don't think a MSR is going to help there, it's more of a technology demo / geology project, because they won't know if the sample has any traces of life in it, and chances are low unless it is easy to find. If easy to find, ExoMars will surely find it first with in situ exploration on Mars.
Anyway - the thing is - that Europa could easily get squeezed out or trimmed down again. While the ESA plans are more certain.
But if the Europa clipper goes ahead and does sample the Europa plumes, it's an exciting project!
NASA Eyes Ambitious Mission to Jupiter's Icy Moon Europa by 2025
As for landing on the surface, it's going to be tricky to be sure the rovers are sterilized to the levels needed to explore Europa without contaminating it with Earth life.
With a deep ocean, and possibly water from that ocean reaching the surface (via the plumes), and possibility of any landing sequence error leading to impact on Europa - has to be really thoroughly sterilized.
On the plus side, Jupiter is surrounded by strong radiation which will help sterilize the spacecraft - indeed the spacecraft systems have to be hardened to withstand the radiation.
It's similar to the Van Allen belts here on Earth - trapped solar particles accelerated in Jupiter's magnetic fields
Like Earth it has aurora where these particles hit the Jupiter atmosphere - but far larger of course.
Hiding from Jupiter's Radiation - Astrobiology Magazine
Still will be one of the main challenges for a Europa mission to the surface, to make sure it is thoroughly sterilized of all Earth life.
That's because though most microbes would be destroyed, a few species microbes are highly resistant to ionizing radiation and can resist astonishing levels of radiation. And also - it only takes one viable microbe to survive to reproduce especially if there is liquid water accessible from the surface of Europa from the water plumes, as seems possible..
The other challenge is to melt the way all the way down to the underlying ocean, and maintain communication with the surface.
On the plus side again though, the plumes are easily sampled. So I expect after these preliminary missions, first missions to Europa will be to sample the water plumes, and continue to survey surface and do what you can by way of analysing it by remote measurements.
That's something we can do at an early stage, and without the planetary protection issues. And if the plume is sampled directly, maybe, with luck, it actually gives us samples from deep down not yet much damaged by the radiation. Though it's not known yet if the plumes are from relatively deep down or a surface phenomenon.
So - hard to say - late 2020s,2030s, ... for missions to the surface. Plumes, who knows, late 2020s.
I wonder if one thing that could accelerate this a little perhaps, is if ExoMars did find life on Mars in 2019 (I don't think there is much chance of Curiosity finding life unambiguously unless very lucky - though it may well find more organics and learn more about the organics there, as it is just not got the life detection equipment needed to distinguish life from organics delivered from meteorites and comets).
That would probably lead to so much interest world wide, I'd imagine, that you might get more funding for these sorts of missions - especially if it turns out to be different from Earth life in some fundamental way (different amino acids, not using DNA etc). But - life hard to find on Mars, chances are, past and present. So - no way to know what will happen there.
Then there's the NASA Europa Clipper - to do flybys of Europa again, hopefully to sample water plumes ejected from Europa and analyse it. But this is a proposal. In the last decadal review they dropped it in favour of a Mars sample return. They might do the same in the next decadal review, as the sample return is a two decade project, and a Europa Clipper is a major expenditure, or they might trim it down as far as they can.
Though I think Mars is well deserving of more study for search for life, I don't think a MSR is going to help there, it's more of a technology demo / geology project, because they won't know if the sample has any traces of life in it, and chances are low unless it is easy to find. If easy to find, ExoMars will surely find it first with in situ exploration on Mars.
Anyway - the thing is - that Europa could easily get squeezed out or trimmed down again. While the ESA plans are more certain.
But if the Europa clipper goes ahead and does sample the Europa plumes, it's an exciting project!
As for landing on the surface, it's going to be tricky to be sure the rovers are sterilized to the levels needed to explore Europa without contaminating it with Earth life.
With a deep ocean, and possibly water from that ocean reaching the surface (via the plumes), and possibility of any landing sequence error leading to impact on Europa - has to be really thoroughly sterilized.
On the plus side, Jupiter is surrounded by strong radiation which will help sterilize the spacecraft - indeed the spacecraft systems have to be hardened to withstand the radiation.
It's similar to the Van Allen belts here on Earth - trapped solar particles accelerated in Jupiter's magnetic fields
Like Earth it has aurora where these particles hit the Jupiter atmosphere - but far larger of course.
Still will be one of the main challenges for a Europa mission to the surface, to make sure it is thoroughly sterilized of all Earth life.
That's because though most microbes would be destroyed, a few species microbes are highly resistant to ionizing radiation and can resist astonishing levels of radiation. And also - it only takes one viable microbe to survive to reproduce especially if there is liquid water accessible from the surface of Europa from the water plumes, as seems possible..
The other challenge is to melt the way all the way down to the underlying ocean, and maintain communication with the surface.
On the plus side again though, the plumes are easily sampled. So I expect after these preliminary missions, first missions to Europa will be to sample the water plumes, and continue to survey surface and do what you can by way of analysing it by remote measurements.
That's something we can do at an early stage, and without the planetary protection issues. And if the plume is sampled directly, maybe, with luck, it actually gives us samples from deep down not yet much damaged by the radiation. Though it's not known yet if the plumes are from relatively deep down or a surface phenomenon.
So - hard to say - late 2020s,2030s, ... for missions to the surface. Plumes, who knows, late 2020s.
I wonder if one thing that could accelerate this a little perhaps, is if ExoMars did find life on Mars in 2019 (I don't think there is much chance of Curiosity finding life unambiguously unless very lucky - though it may well find more organics and learn more about the organics there, as it is just not got the life detection equipment needed to distinguish life from organics delivered from meteorites and comets).
That would probably lead to so much interest world wide, I'd imagine, that you might get more funding for these sorts of missions - especially if it turns out to be different from Earth life in some fundamental way (different amino acids, not using DNA etc). But - life hard to find on Mars, chances are, past and present. So - no way to know what will happen there.
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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