Asteroid Grand Tour Options

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This article from JPL describes recent efforts to derive a main belt multi-asteroid mission trajectory...any of you orbitsmiths out there have some early thoughts/observations?

[Phil Stooke]

"roughly 2,200 asteroids within .1 au."
"That's an average of 2.4 close approaches per day."

It's a nice idea... but 0.1 AU is 15 million km, so most of these are not exactly close approaches in the sense we think of them with typical flybys. You could do great survey work and really expand the phase angle photometry, but you would probably have to work hard to get more than a handful of close approaches.

Phil

[HSchirmer]

"roughly 2,200 asteroids within .1 au."
"That's an average of 2.4 close approaches per day."

It's a nice idea... but 0.1 AU is 15 million km, so most of these are not exactly close approaches in the sense we think of them with typical flybys. You could do great survey work and really expand the phase angle photometry, but you would probably have to work hard to get more than a handful of close approaches.

Phil

Yep, I typed and retyped "close" versus "closest"...
but "close enough for spectra and phase curves" is what you'd get.

(edit)
Hmm, quick fact check- visibility at .5AU.
New Horizons got usable data from two ~100-150 km KBOs at .5 & 1.8AU distance, in really low light.
Illumination comparison would be asteroids at ~3 au versus KBOs ~40AU, is square of distance
so 40AU^2 = 1600 while 3AU^2 ~10, so asteroids get about 160 times the illumination that KBOs do.
KBOs visibility ¶x 150km^2 = 1 illumination unit x .5AU distance
Asteroid visibilty ¶x 12km^2 = 160 illumination units x .5AU distance

So, New Horizon's camera in the asteroid belt could get light curves from 12km objects at .5AU?
Then, eh 5.3km objects within .1AU?

[JRehling]

Certainly it would be desirable to plan the trajectory rather than pick a trajectory and hope for the best. How much good the planning would do is an empirical matter. Probably a little bit of propulsion would go a long way so that a little delta-v before a targeted encounter could set it up to be quite close. It may be that some launch opportunities would be considerably better than others. Of course, some targets are more interesting than others. All told, it's probably better to get 20 to 60 close flybys of interesting targets than to get 1000 distant flybys of random ones. All told, it's a complex paradigm with time as one parameter and assessments of scientific interest as another. And the interest of a set of targets would not the sum of the interest of each of them.

It'd be fun, but hard, to model this out; it's hard to assess how that would go without getting deep into the details.