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_*]

The presentations from the second VEXAG meeting have just arrived ( http://www.lpi.usra.edu/vexag/May2006/presentations.html ). In the one on the latest update of the Solar System Roadmap ( http://www.lpi.usra.edu/vexag/May2006/VEXAG_52006_ELLEN.pdf ), Ellen Stofan's group recommends that for the projected Flagship-class Venus Surface Explorer, an "air mobility platform with long traversing" is now "preferred over a surface rover" for Venus, logically enough. (Not only does it allow much longer traversing, but in the case of Venus it would also allow the vehicle to land, hastily take a look around and grab some samples for later digestion, and then take off again for the cooler upper atmosphere, thereby reducing its heat burden.)

Actually, though, the single most useful presentation from this VEXAG meeting may be Larry Esposito's summation of our current scientific knowledge of Venus ( http://www.lpi.usra.edu/vexag/May2006/Chap...ummaryVEXAG.pdf ).

Also see Emily's series of very useful blog entries on the goings-on at VEXAG ( http://planetary.org/blog/ ).

[nprev]

Mr. Esposito's presentation was indeed informative, Bruce; thanks for posting the link!

2 By of oceans, huh...hmm. Although this is wild speculation, you have to wonder if maybe the advent of photosynthetic life on Earth was what saved us from becoming Venus' slightly bigger sibling in all respects.

Still, if oceans did persist that long, why wasn't more CO2 captured as limestone to prevent a runaway greenhouse? Did Venus all of a sudden become enormously more volcanically active than Earth ever was, causing that 'global resurfacing event' and a CO2 overload in the atmosphere that the oceans just couldn't process fast enough?

Lots of interesting and potentially quite significant contingency scenarios here...