Sol 65 and after, Digs in Neverland, Cupboard, Stone Soup, Burn Alive... |
Sol 65 and after, Digs in Neverland, Cupboard, Stone Soup, Burn Alive... |
Jul 31 2008, 04:55 PM
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Administrator Group: Admin Posts: 5172 Joined: 4-August 05 From: Pasadena, CA, USA, Earth Member No.: 454 |
Since there will be a press briefing today at 11 am PDT / 1800 UT it seems like a good time to start a fresh Phoenix thread. Phoenix hasn't gotten that icy sample yet but they do seem to have overcome their concerns about using TEGA so it looks likely we'll see a lot more sample acquisitions and deliveries in the coming weeks.
Press briefing will be on NASA TV: http://www.nasa.gov/ntv on both public and media channels. Here's that higher-bitrate stream on Yahoo: http://cosmos.bcst.yahoo.com/up/nasa/index.html --Emily -------------------- My website - My Patreon - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
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Jul 31 2008, 05:48 PM
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
To take the question of the rate of circulation -- the water "cycle" on Mars (if indeed a cycle it be), and tie it to the ice sample -- the D:H ratio of the sample could give us a lot of evidence. If this topmost layer of ice has a different D:H than the atmosphere, then it's been here for a long time. Not to make too much of one tiny measurement, but it really is a huge issue:
-- Maybe there is a cycle, but only where the ice is even closer to the surface than it is at the Phoenix site. -- Maybe there is a cycle, but the summertime ice level is some tiny epsilon below the winter ice level, and it's that seasonal epsilon that cycles. If so, a summer measurement of the very topmost ice might show a difference from atmospheric D:H that belies the truth. (With CO2 overlying the H2O in winter, the seasons become very complex with regard to the surface of that H2O layer.) -- Given any possible cycle, the question of how much and how often becomes a "verbose" one. Am I getting too excited over this... because I could see follow-up missions to measure the D:H at a variety of depths and latitudes. It's eminently doable. Is it making too much over too little? It seems to me that the whole martian water cycle is what would be characterized in that way. Moreover, you could play "Twenty Questions" cleverly and end the game by finding negative evidence in the most favorable spot. (Exposed polar H2O ice right before or right after the CO2 covers it.) Can D:H be determined in water ice with any reliability spectroscopically from orbit? That could be the magic measurement. Maybe the data is already in hand?! |
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