Exciting New ‘Enceladus Explorer’ Mission Proposed to Search for Life

by Paul Scott Anderson on February 29, 2012

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Water vapour geysers erupting from Enceladus' south pole. Credit: NASA/JPL

Along with Jupiter’s moon Europa, a tiny Saturnian moon, Enceladus, has become one of the most fascinating places in the solar system and a prime target in the search for extraterrestrial life. Its outward appearance is that of a small, frozen orb, but it revealed some surprises when the Cassini spacecraft gave us our first ever close-up look at this little world – huge geysers of water vapour spewing from its south pole. The implications were thought-provoking: Enceladus, like Europa, may have an ocean of liquid water below the surface. Unlike Europa however, the water is apparently able to make it up to the surface via fissures, erupting out into space as giant plumes.

Now, a new project sponsored by the German Aerospace Center, Enceladus Explorer, was launched on February 22, 2012, in an attempt to answer the question of whether there could be life on (or rather, inside) Enceladus. The project lays the groundwork for a new, ambitious mission being proposed for some time in the future.

Cassini was able to sample some of the plumes directly during its closest approaches to the moon, revealing that they contain water vapour, ice particles and organic molecules. If they originate from a reservoir of subsurface liquid water, as now thought by most scientists involved, it would indicate an environment which could be ideal for life to have started. The necessary ingredients for life (as we know it at least) are all there – water, heat and organic material. The fissures themselves generate much more heat relatively than the surrounding surface, suggesting that the conditions below the surface are much warmer. Maybe not “hot” per se, but warm enough, perhaps also with the aid of salts like in Earth’s oceans, to keep the water liquid.

But what is the best way to search for evidence of life there?  Follow-up missions have been proposed, to again sample the plumes, but with instruments able to look for life itself, which Cassini can’t do. This would seem ideal, as the water is being spewed out into space, with no drilling through the ice necessary. But the Enceladus Explorer project is proposing to do just that; the rationale is that any organisms (most likely microscopic) which may be in the water could easily be destroyed by the force of the ejection from the fissure. So then what is the best way to sample the water itself down below?

Enceladus Explorer would place a base station on the surface near one of the fissures; an ice drilling probe, the IceMole, would then melt its way through the ice crust to a depth of 100-200 metres until it reaches a liquid water reservoir. It would obtain samples of the water and examine them in situ for any traces of microorganisms. With no GPS system available, or external reference points to use, the probe would need to function autonomously, finding its own way through the ice to the water below.

The IceMole is already being tested here on Earth, and has successfully melted its way through the ice of the Morteratsch glacier in Switzerland. The next experiment will have it navigate its way through ice in the Antarctic, sampling completely uncontaminated water from a subsurface lake below the ice, much like the conditions found on Enceladus.

There is no timeframe yet for such a mission, especially given current budgets, but the Enceladus Explorer project has already shown that it is certainly technologically feasible and would provide an incredible look at an environment in the outer solar system which is amazingly Earth-like yet utterly alien at the same time.

About 

Paul Scott Anderson is a freelance space writer with a life-long passion for space exploration and astronomy and has been a long-time member of The Planetary Society. He currently writes for Universe Today and Examiner.com. His own blog The Meridiani Journal is a chronicle of planetary exploration.

Richard_Kirk February 29, 2012 at 10:03 PM

…and when it has sampled the water on Enceladus, it can stick a parachute into one of the plumes, and surf back up into orbit again, and go and visit Io.

Peristroika March 1, 2012 at 3:38 AM

so, um…sail from Saturn orbit to Jupiter? Wow, that’s quite the geyser!

joseluis7696 February 29, 2012 at 10:17 PM

What about the subsurface water that plumes so well, would it no eject the ice mole and perhaps put it in orbit (JJK)?

Peristroika March 1, 2012 at 3:40 AM

The mole lands “near” the geysers, and would probably have some anchoring technique to hold itself in the ice while it samples the water thus keeping it from getting sucked back out.

Mastercope February 29, 2012 at 10:40 PM

The hole the mole :-) would make would more than likely freeze right over again, so surfing with a sail to orbit is highly unlikely. The cost of launching probes is soon going to be bargin basement prices soon. SpaceX is on the Pad and the test for man rating begins.

Mastercope February 29, 2012 at 10:40 PM

The hole the mole :-) would make would more than likely freeze right over again, so surfing with a sail to orbit is highly unlikely. The cost of launching probes is soon going to be bargin basement prices soon. SpaceX is on the Pad and the test for man rating begins.

lcrowell March 1, 2012 at 3:01 AM

To be honest I think they are missing the point of the geysers. A future mission to Saturn should split the craft in a number of smaller mission specific items. One of them, the biggest one in fact, could fly through the geysers with an aerogel. This captures the material, and a propulsion stage then sends it back to Earth. The samples are analysed in the lab on Earth without any hardware limitations of a spacebased system.

Other parts of this craft could put a gravity-B gyroscope system in a close orbit around Saturn. The larger mass and angular momentum should give beefy results on the Lense-Thirring effect. This craft could also observe Saturn up close as well. Maybe something with Titan could be arranged as well.

LC

Peristroika March 1, 2012 at 3:42 AM

I was relieved to hear the initiative was Germany’s. At least with them, we have a chance to fund this within a reasonable time frame. Should probably put a VW logo on the spacecraft!

Torbjörn Larsson March 1, 2012 at 7:29 AM

Too complicated and costly. It is a certainly a good idea to try out an Europa ice drill on something easier, but that should be separate from the goal of making primary science.

There is nothing in our experience that tells us cells will necessary be destroyed by outflow ejection forces or pressure differentials less than a few atmospheres, or that we wouldn’t be able to pick up the residuals. (Of course frozen whole samples are preferable.)

A weak point in sampling the plumes is that surface pockets of waters may be mainly remelts and have little of the ocean water in it. (Though as I now understand it, Enceladus modelers are quite satisfied that there are plenty of connections between the water volumes.) I don’t see that Enceladus Explorer fix that potential sampling problem.

Having to choose between a less attractive ambitious mission and no proposal at all, I’ll take this one of course. I just think an ‘Enceladus Nom Nom Nom de Plume’ mission would be so much more savory.

zetetic elench March 1, 2012 at 2:37 PM

i bet there is hundreds of meters deep of fine snow in the vicinity of those geysers. it would be tricky in the extreme to just land near them and poke around. talk about a complicated design goal. the modular approach sounds best for a first go, with a fly-through/return being just one part. it will require a lot of recon.

magnus.nyborg March 1, 2012 at 2:57 PM

I agree about the tricky endeavour.

And at the conditions, the ‘fine snow’ would probably be more like powdered ice, with stalactite-looking ice-sculpures sticking up everywhere.

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