"thor" Mars Mission To Seek Underground Water Options

[RNeuhaus]

A new, low-cost mission concept to Mars would slam a projectile into the planet's surface in an attempt to look for subsurface water ice.

"I'm interested in exploring mid-latitude areas of Mars that look like they're made of snow and ice," Phil Christensen, the project's principal investigator, told SpaceDaily.com.

Christensen, of Arizona State University, and colleagues at NASA's Jet Propulsion Laboratory, are proposing a mission called THOR – for Tracing Habitability, Organics and Resources – as part of NASA's Mars Scout program.

Like last year's Deep Impact mission to comet Tempel 1, THOR aims to ram a projectile at high speed into the surface of Mars while a host spacecraft remains in orbit and observes the impact and its aftermath. If approved by NASA, the mission would launch in 2011.

That mission would be after MSL's mission. Now it is still a proposal It would cost around US$ 450 millions

More details: http://www.spacedaily.com/reports/THOR_Mar...ound_Water.html

Rodolfo

[Guest_BruceMoomaw_*]

The Europa Penetrator story, as I hinted earlier, may be livening up again:

(1) Paul Lucey told me flatly on Friday that Torrance Johnson was wrong in believing that it's impractical to design a Europa penetrator (or a lunar one) with an attitude-control system which is lightweight but nevertheless capable of pointing the penetrator's nose closely enough toward the direction of motion to prevent disastrous skewing. He also provided considerable technical detail and some supporting testimony from the Discovery proposal review board, which I'll elaborate on later.

(2) No sooner did that happen than a new document turned up on the Outer Planets Assessment Group website ( http://www.lpi.usra.edu/opag/esa_nasa_europa_12_06.pdf ) that dampened my hopes again, in which a new Europa working group stated that a penetrator is impractical for still another reason: "Tom Spilker discussed four independent JPL studies of Lander configurations [presumably the same four that he described for COMPLEX]. The constraints that were applied in the four cases differed. Spilker utilized the results to illustrate limitations on the level of science that can be accommodated within various mass ranges. Some of the key issues link to lack of information about surface properties. For example, he emphasized that the angle of attack of a penetrator cannot diverge by more than 5 degrees from the surface normal and is therefore not under consideration. Of the cases discussed in detail, one in the 60-70 kg range, similar to the 'bowling ball' configuration, seemed to the group worthy of further consideration as a precursor for a sophisticated Lander on a later mission." (pg. 3)

(3) BUT: After I sent that message on to Lucey, he just got back to me an hour ago with the following E-mail: "Spilker misunderstands angle of attack, as does Torrance. The angle of attack is the angle between the velocity vector and the vehicle; this must be below about 10 degrees. This is very easy with simple avionics. The sensitivity to surface-normal is much less; I'm trying to get this number. Penetrator weapons never have a normal incidence." (To a non-scientist, this does indeed seem logical.)

So: after I brought up the possibility of a Europa penetrator at the COMPLEX meeting and Torrance Johnson presented his own technical argument against it, he nevertheless urged me to contact Lucey and find out whether he had any possible solution to the problem. I did so, and Lucey (who knows Johnson) told me he had been unaware of COMPLEX's views on this subject and that he was indeed interested in contacting them about it. I have no idea how this will turn out, but the game seems to be afoot. If anything actually comes out of this, I may have played the role of a data-relay satellite between scientists -- something that has happened on a much smaller scale before, as I imagine it's happened to a number of us.

Again, more technical details on all this later, on our Europa lander thread (including a description of the "bowling ball" impactor mentioned above, which was itself described in great detail at the COMPLEX meeting.) I will say that the penetrator design Lucey has worked out is small enough that two or even three of them could be added to the current Europa Orbiter concept -- reducing the odds of failure -- while still leaving considerable additional mass margin to add additional radiation shielding to prolong the Orbiter's lifetime. If all this be megalomania on my part, make the most of it. But as for whether my ashes would fly on any of them: well, that would be biocontamination, wouldn't it, Alex?

[Guest_AlexBlackwell_*]

But as for whether my ashes would fly on any of them: well, that would be biocontamination, wouldn't it, Alex?

In that case, I suggest a variation of the Pioneer Plaque where the male and female figures are replaced by a line drawing of you pointing towards yourself. Indeed, one might even include a comic strip-type "balloon" dialog box over your head with the words "This is all due to ME!!"