A while back, I read a snippet in a Sci. Am. article about the possibilities of using nuclear-thermal propulsion to power atmosphere probes on the gas giants (namely Jupiter), using the native hydrogen. It sounds like a good idea, if it could ever be made to work. My idea is in a similar vein, but not identical, and I myself admit that it wouldn't be as efficient. But I think it would be cool.
Think: a drone like a cruise missile, that uses a ramjet (or scramjet, if the technology were more developed) to scoop up the jovian atmosphere and combust it with an oxidant. The fact that it would use an onboard fuel source would limit its range and usefulness, of course, but perhaps one could sweeten the deal by having the vehicle jettison a regular Galileo-esque descent module (or better yet, a balloon probe) when the juice runs out.
Here's how I see the pros and cons.
Pros:
--It would be an in situ feasibility study of the usefulness of jets in jovian atmospheres.
--The fact that it could use the abundant hydrogen for an especially vigorous combustion reaction for its engines, which I take would give it a real edge over regular jet engines in Earth's atmosphere.
--It would provide much better horizontal coverage than a descent probe.
--It might provide superior wind data to a descent probe, especially for turbulence studies.
--The opportunity for larger scientific payloads, and perks like imagers.
--Science aside, it would be mad cool. Really.
Cons:
--Faster probes may be more susceptible to damage from turbulence.
--Even in the best case scenario, it would be very heavy.
--There's the issue of keeping LOX fresh and usable for however many years it would take to get to Jupiter, unless someone has a better fuel suggestion (I'm no chemist or engineer).
--There's the problem of making sure the probe would survive the searing entry (and extremely high g-forces) into Jupiter's atmosphere, which would probably be much worse than for the Galileo probe due to its greater weight and sophistication.
--The higher gravity--on Jupiter anyway--would probably dramatically cut down on its efficiency.
--It would be an exceptionally high-risk mission, all told.
In any event, this is just an idea that I've been toying with recently, and I wanted to know what some of the more technically-versed people in this forum thought.