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View Full Version : Solar transit-based mission: feasible or not?



Mithridates
2012-Jun-07, 02:39 AM
I'm curious whether a mission that observes solar transits of planets other than Venus, Mercury and Earth would be feasible or desirable. The mission would be as such:

- powered by an ion drive, very long-term (basically as long as the probe has enough fuel left to refine its orbit), orbits the sun in an orbit that grows as it continues, with a trajectory that takes advantage of as many transits as possible. Bodies with more than minimal atmospheres that could be viewed passing in front of the sun would be: Mars, Jupiter, Saturn, Titan, Uranus, Neptune, Triton.

- it might fly by an asteroid or planet or two if the trajectory allows

- in between observing transits it could also do something similar to what EPOXI is doing now.

Would the ability to see occasional transits of these bodies in front of the sun be worthwhile for exoplanetology, would it cost more than it is worth, or is it simply an unworkable or silly idea?

Jens
2012-Jun-07, 04:10 AM
I think that some missions do end up seeing transits, so for example Cassini has seen transits of earth and Venus, but I don't think it's the kind of thing that would merit a mission of its own. I think it's more something that would be seen as a useful addition to an existing mission with some other purpose. I'm sort of thinking that there are many other missions that would take priority.

antoniseb
2012-Jun-07, 12:24 PM
... be worthwhile for exoplanetology, would it cost more than it is worth ...

So your idea is to make measurements locally (where photons are plentiful) to test out observational techniques for (I'm assuming) observing the properties and composition of atmospheres, and surfaces of non-atmosphere bearing objects as they transit stars.

The idea is workable, but without some more specific goals and experiments, I think making the argument for funding would be difficult. Plus in terms of specific experiments, we'd get measurements and results specific to our kind of star, which might be a fairly narrow group (though arguably valuable).

Mithridates
2012-Jun-08, 12:46 AM
> So your idea is to make measurements locally (where photons are plentiful) to test out observational techniques for (I'm assuming) observing the properties and composition of atmospheres, and surfaces of non-atmosphere bearing objects as they transit stars.

Yes, exactly.

>The idea is workable, but without some more specific goals and experiments, I think making the argument for funding would be difficult. Plus in terms of specific experiments, we'd get measurements and results specific to our kind of star, which might be a fairly narrow group (though arguably valuable).

It would be limited by that, certainly. The upside would be observing transits of gas giants as well as their moons. I imagine Saturn, its rings, some moons without atmospheres and Titan all together would be especially exciting.

Since nobody has completely shot down the idea I assume there must be a concept paper out there somewhere for something similar. In terms of science/excitement per dollar though it would certainly be lower than a lot of other missions.