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#11
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Phoenix Lands on Mars this Sunday!!!
OM wrote:
OM wrote: On Wed, 21 May 2008 00:49:50 GMT, Brian Thorn wrote: Wreckage. I'm betting the next we hear of it is wreckage spotted by MRO sometime next month. ...Part of me is expecting this as well. JPL's been way too cocky about claiming their success at fixing what killed MPL for me to be comfortable about the use of a descent engine system over tried-and-proven airbags. If Phoenix makes an ash out of itself, you can bet your ass that they'll go back to airbags and stick with them for the forseeable future. Sigh... where do I even begin with this? 1) Descent engines are, as far as I'm concerned, just as tried-and-proven as airbags, and more scaleable to larger landers. If Phoenix fails, it won't be due to inherent flaws in powered landings, it'll be due to the same human errors and hubris that killed MCO and MPL. 2) Even if you don't think powered landings are tried-and-proven, should it be NASA's job to only stick to what's tried-and-proven? If that were the case, they'd rarely achieve anything new. Shoot, they never would have attempted airbags in the first place. 3) If Phoenix fails and NASA (irrationally, in my not-so-humble-opinion) goes back to airbags and sticks with them, then it's highly unlikely we'd ever see Mars landers much larger than the MERs. No sample return mission, and definitely no manned landings. In short, be careful what you wish for. |
#12
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Phoenix Lands on Mars this Sunday!!!
OM wrote: ...Part of me is expecting this as well. JPL's been way too cocky about claiming their success at fixing what killed MPL for me to be comfortable about the use of a descent engine system over tried-and-proven airbags. If Phoenix makes an ash out of itself, you can bet your ass that they'll go back to airbags and stick with them for the forseeable future. I like the concept of it landing just fine, but the heat of its landing engines rupturing the dry ice over the liquid CO2 that is apparently underground at the pole, so that the lander goes flying right back skyward on a CO2 geyser: http://seedmagazine.com/news/2006/08...with_carbo.php :-D It's interesting in that article how they are fine with high pressure CO2 gas under the ice, but aren't going to mention liquid CO2 down there, even though the pressures and temperatures are right for it to occur...as soon as you open that can of worms, then a lot of those "water-related" features on the surface of Mars have a whole other explanation possible, and the Mars probe funding starts to dry up: http://www.spacedaily.com/news/mars-...ence-00k1.html Just a few days ago, new evidence emerged of a Mars that is colder internally than was suspected: http://spaceflightnow.com/news/n0805/15marsinterior/ Pat |
#13
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Phoenix Lands on Mars this Sunday!!!
jonathan wrote: Phoenix Home http://www.nasa.gov/mission_pages/ph...ain/index.html News Release http://marsprogram.jpl.nasa.gov/news...20080516a.html Anyone care to stick their necks out and make predictions on what they'll find? 1) Spheres? 2) Organic material? 3) Will they find the northern lowlands used to be covered by a sea? 4) habitable? I'm saying yes on all counts. Good luck Phoenix! s I'll say no on most counts. Nothing organic. Perhaps some ice. Toxic dirt. |
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Phoenix Lands on Mars this Sunday!!!
Damon Hill wrote:
I'll second that; too bad the Russians haven't sent anything that way recently. The GMG has had an insatiable appetite for Soviet/Russian spacecraft. He's also snacked on ours, gone on a Japanese diet, and had an English snack along with High Tea. |
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Phoenix Lands on Mars this Sunday!!!
On May 20, 6:42 pm, "Alan Erskine" wrote:
I saw the NASA TV media briefing on the landing a couple of days ago. The reason for using thrusters instead of air bags is that the bags have limitations on how much mass they can land. Well, in that case, getting experience landing something heavier will help when it comes time to land people on Mars. John Savard |
#16
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Phoenix Lands on Mars this Sunday!!!
"Pat Flannery" wrote in message dakotatelephone... OM wrote: ...Part of me is expecting this as well. JPL's been way too cocky about claiming their success at fixing what killed MPL for me to be comfortable about the use of a descent engine system over tried-and-proven airbags. If Phoenix makes an ash out of itself, you can bet your ass that they'll go back to airbags and stick with them for the forseeable future. I like the concept of it landing just fine, but the heat of its landing engines rupturing the dry ice over the liquid CO2 that is apparently underground at the pole, so that the lander goes flying right back skyward on a CO2 geyser: I think the CO2 ice is mostly in the south pole. The north has most of the water ice. From what I've read, they expect to land in an area where the top meter of ground is 60 to 80 percent water ice. So it should be like a dry antartic site. Not a sheet of ice but very frozen water rich soil. The northern lowlands are several miles below the highlands, so it has slightly thicker and warmer atmosphere. And this chart shows just how much water exists in the first meter of soil planet wide. http://www.nasa.gov/mission_pages/ph...-20080513.html What strikes me is that if Mars has been dry and cold for geologic time, why would the first meter of soil still have such a large concentration of water ice? I think we're going to learn someday that Mars has ice ages. And periodically the ice melts out from underground. Keeping the near surface icey. If some crater or canyon becomes filled from underground, it would ice over. And the ice cap would abate away fairly slowly in comparison with being filled by an underground spring. Water, lakes and such could exist with the thin atmosphere if underground water melts out as ice ages wax and wane. The assumption that since the atmostphere thinned over a billion years ago, doesn't mean the surface has been dry at that time. Quite the opposite it seems. Look carefully at the ....shadows...in each of these pics. And also the general surface texture. Keeping in mind that the mars pic is on a roughly ten degree slope. But the delicate erosion pattern cast in each /shadow/ is the same, and the result of water eroding away the soil. How long ago was Mars wet??? To say geologic time seems absurd. Yellowstone mudpot http://www.nps.gov/yell/slidefile/th...ages/05402.jpg Endurance mudpot http://qt.exploratorium.edu/mars/opp...1P2397R1M1.JPG http://seedmagazine.com/news/2006/08...with_carbo.php :-D It's interesting in that article how they are fine with high pressure CO2 gas under the ice, but aren't going to mention liquid CO2 down there, even though the pressures and temperatures are right for it to occur...as soon as you open that can of worms, then a lot of those "water-related" features on the surface of Mars have a whole other explanation possible, and the Mars probe funding starts to dry up: http://www.spacedaily.com/news/mars-...ence-00k1.html Just a few days ago, new evidence emerged of a Mars that is colder internally than was suspected: http://spaceflightnow.com/news/n0805/15marsinterior/ Pat |
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Phoenix Lands on Mars this Sunday!!!
On May 20, 4:31 pm, "jonathan" wrote:
Phoenix Homehttp://www.nasa.gov/mission_pages/phoenix/main/index.html News Releasehttp://marsprogram.jpl.nasa.gov/newsroom/pressreleases/20080516a.html Anyone care to stick their necks out and make predictions on what they'll find? 1) Spheres? 2) Organic material? 3) Will they find the northern lowlands used to be covered by a sea? 4) habitable? I'm saying yes on all counts. Good luck Phoenix! s See my article he http://sciencedude.freedomblogging.c...nding-preview/ |
#18
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Phoenix Lands on Mars this Sunday!!!
Damon Hill wrote:
Isn't MSL a more likely candidate for a GMG meal? I've seen the animation of that mission's landing and a lot can go wrong with the skycrane lander that will deploy the rover. |
#19
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Phoenix Lands on Mars this Sunday!!!
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#20
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Phoenix Lands on Mars this Sunday!!!
"Matt Wiser" wrote in
: Damon Hill wrote: Isn't MSL a more likely candidate for a GMG meal? I've seen the animation of that mission's landing and a lot can go wrong with the skycrane lander that will deploy the rover. Yeah, a hover-winch; I'm sure we'll all be sweating that one's crunchdown. --Damon |
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