Future Venus Missions Options

[Phil Stooke]

Oh well, might as well start that new topic since it's already well advanced in the Juno area...

My perspective on landers is as follows. All the landers we've had so far were dropped blind onto an essentially unknown surface. Any future landers can be targeted for specific terrains. It really is not true that we have had representative landings. Even a descent image or two, a panoramic photo plus a bit of surface composition, from a simple Venera-class lander just updated a bit, would be useful if we could put several down at well chosen targets. My choices would be:

Examples of the main plains units (smooth, fractured, ridged)

tesserae

high elevation radar-bright tesserae

large fresh lava flow unit ('fluctus')

crater dark parabola

crater ejecta outflow unit

dunes area.

And I have always assumed, rightly or wrongly, that it would be relatively easy to put these down, so they ought to be fairly inexpensive as planetary landers go.

Phil

[Guest_BruceMoomaw_*]

NASA's Venus Exploration Analysis Group (VEXAG) -- the new equivalent of MEPAG and OPAG -- held its first meeting yesterday in Pasadena ( http://www.lpi.usra.edu/vexag/vexag.html ). While I missed the morning session because I had to catch the final part of the COMPLEX meeting, I did manage to catch the afternoon session.

Unfortunately, not much was said then -- except that the subgroup that deals with "Planetary Formation and Evolution" (that is, surface studies as opposed to atmosphere studies) came up, during a session at the meeting itself, with what Steve Mackwell regards as a very good initial list of desired science measurements, along with information on how technologically difficult they will be. In the next two weeks, the subgroup will prioritize and finalize this list, and he's promised to send their conclusions to me -- although I imagine I'll be using those in my "Astronomy" article and so may not be free to announce them here. (I will say that he agreed with me that, since the minimal estimate for the cost of a Venus sample return is $10 billion, Congress will fund that mission on about the same day that O.J. finds the real killers. We will have to settle for in-situ measurements instead.)

Mewanwhile, three of the Powerpoint presentations from the meeting have just been put on its site at http://www.lpi.usra.edu/vexag/1st_comm_meeting.html . Three of them are disappointing, but there's a very nicely detailed description of the precise measurments that MESSENGER will make during its second Venus fyby in June 2007. (The instruments will be off during the first one in Oct. 2006, because it's near solar conjunction and the flyby is rather distant anyway).
http://www.lpi.usra.edu/vexag/Nov2005/MESSENGER_VEXAG.pdf