Occultation mission proposal Options

[tasp]

{if this is already under discussion, my apologies}

How about throwing together some 'off the shelf' technology and putting together a fun, cheap, and useful mission?

I have noted in Sky and Tel, and Astronomy frequent updates for amatuer astronomers who want to observe solar system objects occulting brighter stars. Also, Voyager 2 famously watched beta Scorpii pass behind the rings of Saturn many years ago.

Would a spacecraft mission to do this be a good use of resources?

I am thinking a good imaging system (maybe derived from Deep Impact), a high speed spectroscopy instrument (surely something appropriate exists) and the ion drive from the Ceres/Vesta mission culd be put together and launched (on a 'cheap' rocket) for a relatively small budget.

What can we do with this?

All solar system objects cast shadows of all stars (think about it). This spacecraft would just fly from shadow to shadow, and watch the ingress and egress of the stellar light in proximity to the target object.

Want an ocultation of a spectral class F star by the southern polar regions of Enceladus? Look at all the possibilities and pick the one that takes the least delta v top get to.

Want an ocultation of an O star by Deimos? A K star by Charon? An A star by Venus?


With so many appropriate stars (ok, the ones close to the ecliptic) and a craft with a good manuvering system, useful occultations could be arranged, I dare say weekly, or even more often.

The data processing requirements for this mission are starting to seem a little extreme to me now, but an analog of 'SETI at Home' could bring an enormous amount of processing power at low cost. Also, wouldn't it be great if your own PC ID'd an occultation of Xena that was conducted and confirmed neon in it's atmosphere?


Think how many solar system objects are now known (scads!) and how many of their shadows crisscross space from all the stars brighter than let's say 10th magnitude.

We would be getting physical dimension data, and spectral absorbtion data on possible atmospheres on many, many objects. Secondary events could confirm new satellites and rings too, or exclude them.

[Bob Shaw]

Tasp:

Yes.

Let's get together and build a UMSF CubeSat.

Bob Shaw

[edstrick]

There's a fundamental problem to doing an inexpensive occultation mission. Most observations are photon-starved. An occultation of a 7'th or 9'th magnitude star by 13'th magnitude Pluto just doesn't have many photons per square meter, especially when you want to take data FAST.

Asteroid occultations of brighter stars are not uncommon, that's why it's easy to get amateur astronomers lined up across a plotted occultation track, but all you're trying to get is "off / on" timing to get diameter and limb shape.

In occultations of things with atmospheres (or if you're searching for atmosphere), you really need high signal-to-noise and that means lots of photons, meaning BIG optics.

I hate to throw cold water on a good idea, but I think it's not likely to be easy.

[tasp]

Long focal length not being the same as big aperture.

Thanx for the dose of reality. My thinking was the data processing to find the shadows for an object in a continuously changing solar orbit would be the major difficulty.

[Bob Shaw]

Long focal length not being the same as big aperture.

Thanx for the dose of reality. My thinking was the data processing to find the shadows for an object in a continuously changing solar orbit would be the major difficulty.

Well, we'll just have to get a piggy-back ride for UMSFsat-1 on NH2!

Get closer to the action, see...

...now, as to the solar array size...

Bob Shaw