The recent conclusions drawn from the data returned from the Cassini probe, indicating that this interesting Moon of Saturn probably has a huge salty liquid water ocean beneath its icy crust makes it a very important target for further exploration. We need to explore this ocean to see if there is any evidence that life has evolved there; as this will be positive evidence of a second Genesis. Even if we find either active life or fossil life on Mars, there will always be the question of cross contamination between Earth and Mars; We have already seen at least one meteorite that originate from Mars, which may contain evidence of fossilized lifeforms. Likewise I am sure that future exploration of the Red Planet will unearth (unmars;-) samples of our planet that has been smashed out of our mantle by a cosmic collision and has ended up impacting our relatively close planetary companion, which may have been carrying who knows what biological payload. Even if chunks of the Earth had reached Enceladus; the chances of it penetrating the ice crust to contaminate the under surface ocean is negligible. So if there is life there it must have evolved totally separately. One theory is that life evolved on Earth around the undersea volcanic vents. Would it be too surprising if Enceladus had an analogous phenomena; look at the volcanic activity on IO and Titan; so it wouldn't be such a stretch of the imagination to expect to see the same sort of thing on the Enceladus sea floor.
If the weakness in the Tiger stripes can let the water rush out into open space, then this is probably a good place to look for an entrance for our probes into the ocean – if the stripes let the water come out, then by putting sufficient back pressure on a vent to stop the Water rushing out, will leave a nice hole in the ice through which we can simply drop our probe (wishful thinking if ever I heard it ;-) There is a lot of research that needs doing before such an exploration could start, for example
1) Through ice communication.
2) Underwater propulsion
3) Under ice navigation techniques
4) Power supplies for prolonged underwater exploration
5) Adaptive sensors, and control programs
6) Swarm 'intelligence' so you can use multiple probes in one exploration
I am sure there are hundreds of other topics I have missed; however much of this research can be done by relatively small Universities all over the World, each given a self contained package, all aimed at the most advanced, almost intelligent robot system to come out of our planet. The partial systems can be tested firstly in the oceans – we know there is life there; then a more complete system could be tested in Lake Vostok in the Antarctic, as the closest simulation of the Enceladus environment we have on Earth; and when it is complete we can implement first on Enceladus; then on Europa, which I believe there is strong but indirect evidence may also have such an under ice ocean.
Finding a second Genesis within our own Solar System would do remarkable things to the statistics for the probability of finding intelligence elsewhere in our Galaxy, and beyond; and allowing a much more accurate estimate of some of the guesswork parameters left in the Drake Equation
Can we simply examine the plumes from orbit as Cassini did, only with more sophisticated, biosensing instruments? If the subsurface ocean is anything like oceans on Earth, traces of life should be abundant in any tiny speck of water to emerge from there.
I think that not only we can - we should do exactly what you suggest ( although whether it is 'simply' as you state I think that is wishful thinking;-) Unambiguous evidence that a second Genesis has occurred anywhere in the Universe is vitally important to our search for extraterrestrial intelligence. Can you imagine what a discovery in our own Solar System would do for the Statistics of finding life in other star systems. As I stated in my first letter I am not sure whether discovery of Life on Mars could be used as clear evidence that such a second start for life has occurred. I think whether such a discovery from an orbiting spacecraft will still not tell us if really complex lifeforms exist in the Ocean or are we dealing with microbiological lifeforms only
What excites me is that a combined World descision to go and explore the oceans of Enceladus could lead to a major impetus to the design of Robotics, and undersea exploration. True much work is going on in the oceans of the Earth, but they are so local that sending Men to do the exploration, rather than really smart Robots, that we can only currently dream of, will be the more economical option. This is something that will not be the best route for the exploration of the Ice Moons of the giant planets.