I'm still waiting to hear the point of sending the Hubble to the Asteroid belt. Is it so it'd be closer to the stars? :-)

--Greg

Well, unless NASA don't know what to do with its budget, this may be an exotic idea to try

I'd rather like to see a Cassini-class mission to Uranus, and Neptune also.

No, closer to the asteroids! Yes, the cost of modifying it well exceeds anything rational, it was more in jest than being serious.

It is worth noting that some attempts to image NEOs have wound up smeared, as did many of the ACS HRC lunar images (although some were sharp). Hubble isn't designed to track objects at close range.

Hmm. You know, what might be an interesting mission would be a space telescope specifically designed to obtain high-res imagery of Solar System objects: a big, fat light bucket or multiple mirror device with a short focal length (hope I said that right) capable of getting at least 1 km resolution all the way out to Triton.

You could map all the major asteroids pretty easily, I'd think, resolve Jupiter's Trojans, image Chiron, monitor Titan & Enceladus, etc. Plus, it would be a nice technology demo for the TPF.

nprev, I wonder if another James Webb Space Telescope (this one with visible wavelength) is suitable for this mission or not?

Btw, I think such device must have a very long focal length in order to get high magnification/resolution - JWST's is at an incredible 131.4 m

Thanks for the focal length clarification, Thu; was fairly sure that I screwed that up!

Just seems to me that the really far-out concepts that have been floated for TPF could be refined by using space-based advanced 'scopes for Solar System mapping. We'd all rather send spacecraft, of course, but if nothing else a Solar System Mapping Telescope (SSMT) would reveal features of interest on unvisited bodies and thereby refine the mission selection process. Additionally, long-term monitoring of the known active places like Io, Titan, Enceladus, and Triton seems a lot more cost-effective using an instrument capable of examining all of them periodically.

Here's another thought I floated earlier, but may bear repeating: How about a Mars orbiter equipped to detect transient events?

What I'm thinking here is a wide-field camera coupled with moving target indication software, operating in real time (no recording unless commanded). After substracting the inherent overfly motion of the spacecraft, any detected movement over a 1-5 sec timeframe triggers a narrow field cam to zoom in & record the event...landslide, CO2 geyser, dust devil, streak formation, meteor impact...hot spring emission?...

Scientifically and pragmatically, understanding the currently active processes on Mars seems crucial for formulation of long-term exploration strategies. Hard to do that well without establishing the frequency and complete nature of such events.

Also, from a marketing standpoint, can you imagine a more exciting orbiter mission? Can't overlook the cool factor.

I think aperture would ultimately decide the resolution, or separation of the elements if it is an interferometer. The JWST would have much less aperture than existing (and planned) ground based telescopes. To get 1km resolution at Triton would be very roughly 50 microarcseconds. Since an aperture of about .15m can resolve 1 arcsecond, one would multiply that by 20000 to get a needed value of 3000m aperture. So a well designed interferometer having that separation would be needed. I wonder how good quality of imagery though an interferometer can get compared with an actual telescope of the same aperture?

How about resolving the photosphere of another star? Far more than you ever wanted to know, here.

Yes, some of those images of Betelgeuse look nice. I like it when they show an image as it might appear to the eye vs a contour plot or something similar. I would look more specifically for a comparison of imagery using an interferometer side by side with a telescope of the same aperture if that is readily available.

FWIW, the 1km at Triton criterion we mentioned earlier would be about 500 times better resolution than the Betelgeuse observations.

Very interesting idea. However, it will be technically challenging. To catch most transient events, you need a relatively high resolution (e.g. CTX-like). Having a wide area coverage with such as resolution probably needs a telescope like LSST. Even if you can get such a behemoth into the Mars orbit, the amount of data it generates needs a supercomputer to process. A typical RAD6000 computer used in most of the recent Mars probes is orders of magnitude weaker than needed for this task (in fact, it is not even as powerful as a common PDA).

Now, looking for meteor impact is another story. I guess it is technically feasible. You need a relatively low-resolution IR telescope (it might be even better if it only looks at the night side, maybe park it in L2 point). IIRC, the expected impact frequency is 10-20/yr. As such low rate, it might be difficult to justify the expense and trouble of such a mission, even if it has a discovery price tag.

Doesn't that need some kind of qualifier? What scale are you talking about?

Use a RAD750 then. Very nearly 10x the processing power of a RAD6000. For the sort of number crunching involved or this - you would have a FPGA on the instrument itself anyway. Think of the FPGAs on HiRISE processing 28.6 megapixels per ccd per second. I'm sure if the need was there, it could be done with no problems at all.

IIRC, this is the figure quoted in the Science paper describing the discovery of fresh impact crates on Mars using MGS (extrapolating from the area covered by MGS and the length of time...). I guess it is the expected number of meteors that survived traveling through the atmosphere (i.e. became a meteorite) and made a sizable crater detectable by MGS.