[X] My Assistant

[Guest_Richard Trigaux_*]

James Oberg Chimes in:
Let Us Drink from the Fountains of Enceladus

The idea is as follows: send a stardust-like mission to capture particules from the Enceladus plume.

I think it is the cheapest way to have infos on what is going on into Enceladus, if it has a biochemistry and how far it evolved.

I allow myself to better the idea: the probe could have three targets.


1) when passing near Saturn, catches ring particules
2) Using Titan as a gravitationnal aid, captures smog particules (fortunately they reach very high)
3) passes into Enceladus plume, captures eventual evidences of biochemistry in Enceladus.

And back to Earth! It even don't need to actually satellise around Saturn, if it is well aimed. The only difficulty is a precise navigation, to aim into a 10x10kms window into the plumes, and a bit of fuel.

The only serious problem is not to bring back some alien bacteria on Earth! Eventually the aerogel containing the Enceladus particules would be coated in something after use, so that there would be no possible contamination, in any way.

Even if the mission fails, a low pass over the Tiger Stripes would allow to obtain precise images of the vents (or more likely zones where the ice is sublimating, like in a comet), provided we have a special shutter compensating for motion blur. Such images would be anyway a necessary preliminary step before sending a lander on Enceladus, and even before designing it (depending on the geometry of the vents, which may be complicated or hazardoous).

[tty]

Anybody have any bright ideas about how to collect atoms coming in at 30 kms-1, sort them out and store the ones you want to keep? I don't say it's impossible, but methinks it's rather considerably beyond the state of the art so to speak.

Another problem nobody seems to have discussed. The material we want to catch from Titan and Enceladus is largely organics and volatiles, so it must be collected at rather low relative speed or it will melt or even vaporize on impact. Also it should be stored at low, preferably cryogenic, temperatures all the way back to Earth and through the landing. If we keep the collectors in an absolutely gas-tight container the temperature requirements could be less tight since the collected materials would still be around though in liquid or gas form. However many of the most interesting compounds, especially from Titan, might be changed beyond recognition.

tty

[Guest_Richard Trigaux_*]

Another problem nobody seems to have discussed. The material we want to catch from Titan and Enceladus is largely organics and volatiles, so it must be collected at rather low relative speed or it will melt or even vaporize on impact. Also it should be stored at low, preferably cryogenic, temperatures all the way back to Earth and through the landing. If we keep the collectors in an absolutely gas-tight container the temperature requirements could be less tight since the collected materials would still be around though in liquid or gas form. However many of the most interesting compounds, especially from Titan, might be changed beyond recognition.

tty

This is an interesting question.

First, what is interesting in Enceladus plume, is not gas or water, but eventual larger solid particules, which would contain complex organic molecules, eventually proto-life. Aerogel would catch them easily. Of course, we cannot expect to find living bacteria in the aerogel (even if there are in the plume) but molecules like RNA, proteins, cell membranes, catalysts, would be easily recognizable. Even ribosomes or centrosomes would be. At a pinch, it would be safier not to bring back alien living bacteria on Earth...

Gas or water are not interesting to bring back, as every water is like Earth water. We just need the quantities. Eventually a good motive to bring them back on Earth would be isotopic analysis, or trace elements.

For this I think we don't really need a cryogenic (and it would be difficult to build, requiring a heavy coolant tank, to work for years). It would be enough to have an airtight container (eventually self-welding) with a small tap to examine gasses before opening the container. But from the experience of the unhappy Genesis probe, it would be better if this container would be able to survive without its parachute... especially if it contains alien bacteria.


I just wonder of an idea to safely receipt contaminated sample return capsules: using the Moon as a gravitationnal aid, to plave the capsule on an orbit around Earth in place of directly receiving it on the ground. Of course it would be costy to recover from its orbit, but much less costy than some devastative epidemy. Such a recovery would be a good use for a space station (at last one ). And if the crew is contaminated, we just sacrifice the station and crew to avoid contaminate the Earth.