[X] My Assistant

[Guest_AlexBlackwell_*]

I'm not sure exactly which forum this fits in but NASA has just released the AO for Discovery Program 2006 and Missions of Opportunity. See the Discovery Program Acquisition Home Page for more details. Click on the "Discovery AO" link to download the PDF.

[Guest_BruceMoomaw_*]

There are at least three Venus Discovery proposals coming up in this round:

(1) VESPER will be resubmitted -- despite the fact that Venus Express should achieve many of its goals. It will be jazzed up by adding the little "VAMP" entry probe that was separately proposed once before. (VAMP's descent camera, which could have provided only very fuzzy high-altitude views, will be replaced by an improved GCMS).

(2) Poor Kevin Baines -- having submitted VESAT five times and struck out repeatedly (sometimes by heartbreakingly close margins) -- has given up on it and will be submitting a cloud-level balloon with a GCMS for protracted atmospheric and cloud studies.

(3) Bruce Campbell will be proposing "VISTA", an orbiter with the kind of subsurface radar sounder that got kicked off Venus Express due to lack of funds (plus a radar altimeter that's higher-resolution than Magellan's, which might allow much better gravity mapping). It may actually be the same "VENSIS" sounder planned for Venus Express -- that is, a clone of MARSIS. He's very skeptical about the ability to age-date Venusian rocks because of their high temperature, and thinks that the stratigraphy which a subsurface radar sounder can provide may be the only way to properly sequence the geological events that actually happened on Venus -- including settling the major question of whether it really did undergo catastrophic resurfacing. He told me at the VEXAG meeting that he simply considers this higher-priority scientifically right now than getting higher-resolution SAR images of Venus, which he could have done if he had instead proposed a Venusian copy of his "Mars Scout Radar" proposal.

I don't think the Discovery program is being deliberately "morphed into a comet/asteroid program" -- but I do think that they are finally running out of really low-cost Solar System missions that can do really good new science (at least until new technologies gradually lower the cost of the missions again), and so small bodies are likely to dominate the program more and more. Certainly, given the need to sample as wide a variety of asteroids, comets and KBOs as possible, missions to visit multiple small-body targets would seem a good, cost-effective choice for the Discovery Program at this point.

In any case, Bush's lunar initiative has now devoured all possible Discovery lunar proposals -- and the Mars Scout program, from its start, included all Phobos/Deimos missions (thus infuriating Jeffrey Bell, who admittedly infuriates easily). As for extrasolar-planet astronomy satellites, keep in mind that Kepler's cost has mushroomed to over $500 million -- with NASA's new Universe Division neverthless continuing to support it on the grounds that it's now an integral part of the extrasolar-planet search program (which, as Andy Dantzler said, means that "I don't have to worry about the thing anymore.") If later extrasolar-planet Discovery proposals are likely to undergo comparable cost overruns, this of course reduces their chances of being picked. It will be interesting to see whether they get enough science out of the damaged Genesis samples to rule out any thoughts of a reflight -- especially since oxygen and nitrogen measurements were both its highest scientific priorities and the ones most seriously contaminated by the crash.

But those last two categories raise the question of whether it might be better for NASA to combine ALL its competitively-picked space science missions within the same cost band into a unified competition, regardless of whether they happen to be Solar System, astronomy, or Sun-Earth Connection studies. (I've already mentioned that the possibility has been raised of incorporating Solar Probe into the New Frontiers program, since it's in the same price range.) This would seem to be more scientifically cost-effective overall.