Second MSL Landing Site Workshop, October 23-25, 2007 |
Second MSL Landing Site Workshop, October 23-25, 2007 |
Guest_AlexBlackwell_* |
Sep 10 2007, 07:47 PM
Post
#1
|
Guests |
SECOND LANDING SITE WORKSHOP FOR THE 2009 MARS SCIENCE LABORATORY
October 23-25, 2007 Pasadena, CA Announcement (MS Word) Information to Presenters (MS Word) Note also the two August 2007 updates for MSL Landing Site Selection: User’s Guide to Engineering Constraints. |
|
|
Oct 26 2007, 05:33 AM
Post
#2
|
|
Senior Member Group: Members Posts: 3419 Joined: 9-February 04 From: Minneapolis, MN, USA Member No.: 15 |
In my humble opinion, the phyllosilicates are a number one priority. These clays seem to be the only things that preserve traces of a Mars which differs significantly from the current planet.
They may have been formed as early as at the very end of the LHB, but these clays were formed before sulphuric acids began pouring out of the interior and the entire outer surface of the planet was coated with sulphates. This is likely the only period in the history of Mars when conditions were truly favorable for life to develop, and as such are most interesting to me. (It has always seemed to me that we need to study extraterrestrial life before we can truly understand how life actually works. Until then, we're stuck behind assumptions that we can't see beyond.) There seems to be precious little of this phyllosilicate material exposed on the surface. The question is, was there not much to begin with? Or was it more ubiquitous but now has been covered with lavas and/or coated with basaltic dust cemented together by sulphate salts? Investigations of the clays, and of the contact between them and the surrounding terrains, will go a long way towards painting a picture of very early conditions on Mars. Now, if Meridiani shows significant clay exposures, I'd be all for landing there. We already know how benign the surface conditions are, and how likely it'll be that we can land MSL there safely. But the more we can place clay exposures into a geologically significant context, the more we learn. I'm not positive how much context we'll be able to derive in such a flat location -- you'd be almost totally dependent on entering medium- to large-sized craters to get your drill holes into the stratigraphy. I'd rather find places we can land safely and then approach outcrops on cliff faces and hillsides. Seems a little more likely to show us context. Of course, I could be wrong... -the other Doug -------------------- “The trouble ain't that there is too many fools, but that the lightning ain't distributed right.” -Mark Twain
|
|
|
Oct 27 2007, 02:11 AM
Post
#3
|
|
Member Group: Members Posts: 384 Joined: 4-January 07 Member No.: 1555 |
In my humble opinion, the phyllosilicates are a number one priority...They may have been formed as early as at the very end of the LHB, but these clays were formed before sulphuric acids began pouring out of the interior and the entire outer surface of the planet was coated with sulphates...There seems to be precious little of this phyllosilicate material exposed on the surface. The question is, was there not much to begin with? Or was it more ubiquitous but now has been covered with lavas and/or coated with basaltic dust cemented together by sulphate salts? Investigations of the clays, and of the contact between them and the surrounding terrains, will go a long way towards painting a picture of very early conditions on Mars. -the other Doug Other Doug - Great insights. Actually, the phyllosilicates may have formed as a RESULT of (that is, at the height of) the LHB - that period may well have been the warmest, wettest, most energy-rich time in martian history. (Remember, unequivocal signs of life appeared on Earth shortly after the end of its own LHB, other evidence of which has since been largely erased.) A life-hostile late episode of "sulfuric acids pouring out of the interior" is only one possible interpretation of the sulfate-rich surface of Mars, one that I consider rather unlikely. Others include weathering of igneous sulfides excavated by impacts (my "mine dump" modification of Roger Burns' gossan suggestion), and/or acid sulfate condensation/redistribution by impacts followed by the inability of frost or snow to leach these sulfates away from the surface (chlorides being much easier to leach, although some appear to have survived). The result was called sulfate duricrust back in Viking days and blamed on capillarity; effloresecent sulfate crusts on mine dumps form similarly. Later impacts (those occurring at the tail end of the LHB, after Mars had already seriously cooled down, or afterwards) may well have covered up many of the early clays (in addition to areas covered by late volcanism and wind). That at least is one interpretation of the impact deposits (if that's what they are) that appear to cover clay-rich sediments at both Meridiani and Gusev. Phyllosilicates (clays) are excellent at absorping organic molecules, and I agree with you that fresh exposures of clays (as verified by CRISM and OMEGA) should therefore be priority number 1 for astrobiology (and for the MSL). I merely hypothesize that "very early conditions on Mars" (insofar as we can know them) were clearly dominated by impact cratering of the LHB, and much that we see today can still be attributed to that episode, either directly (e.g., craters and their distal deposits) or indirectly (e.g., impact-related ephemeral climate change; impact erosion of atmosphere). Whether or not life arose during those exciting times on Mars (as it may well have on Earth) remains to be determined. My personal favorite target for astrobiology might be rocks near the throat of a Tharsis volcano. Three billion years of near-constant heat, moisture, and chemical nutrients potentially could have provided a life-friendly environment impossible on Earth owing to plate tectonic movements. Of course, MSL is hardly going to land on top of a big volcano if it can help it. -- HDP Don |
|
|
Lo-Fi Version | Time is now: 22nd September 2024 - 04:28 PM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE COPYRIGHT |
OPINIONS AND MODERATION Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators. |
SUPPORT THE FORUM Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |