Gut feeling... |
Gut feeling... |
May 23 2008, 01:26 PM
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#31
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Founder Group: Chairman Posts: 14434 Joined: 8-February 04 Member No.: 1 |
5mph they keep saying - 2.5ish m/sec
2.5 m/sec to a standstill in, say, .25 seconds - 1G. Atmospheric entry and the chute-deployment snap will be much higher than that, 6, 7, 8, 9 G sort of figures. Doug |
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May 23 2008, 01:32 PM
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#32
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The Poet Dude Group: Moderator Posts: 5551 Joined: 15-March 04 From: Kendal, Cumbria, UK Member No.: 60 |
To be honest I can't even bring myself to think of a figure; a little part of me thinks that doing so would jinx the mission, so sorry, no percentage from me. I do, though, think that it's quite unlikely Phoenix will land on perfectly flat ground, having seen the latest HiRISE images. There are so many mounds, trenches and ridges that I'm pretty confident that our first images of the landscape will show the horizon at an angle.
I just finished work for the long Bank Holiday weekend, and I'm not in again until Tuesday afternoon. Strange to think that the next time I walk through the door at work we'll either have a new probe on Mars, sending back new pictures and data, or we'll all be spectators to another Beagle- or MPL-like interplanetary post-mortem... My "gut feeling" isn't a percentage, it's a word: sick... -------------------- |
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May 23 2008, 02:11 PM
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#33
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Founder Group: Chairman Posts: 14434 Joined: 8-February 04 Member No.: 1 |
I am genuinely beginning to get a physical reaction to the tension of the whole thing. Phoenix is making me physically nervous already. Quite what I'll be like on Sunday I don't know.
Doug |
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May 23 2008, 02:23 PM
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#34
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Merciless Robot Group: Admin Posts: 8785 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Be chilly, you guys, keep an even keel...really, it's gonna be alright. Don't know why I know it, but I know it.
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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May 23 2008, 02:29 PM
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#35
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Senior Member Group: Moderator Posts: 2262 Joined: 9-February 04 From: Melbourne - Oz Member No.: 16 |
Me too, I've already got that nervous-butterfly's-in-stomach feeling., I'm going to be wreck come Sunday night!
Made the decision today to take Tuesday and Wednesday off work next week, in addition to the Bank Holiday Monday, to recover and work full time on Phoenix data*. * That in the spirit of this thread I'm 90% sure we'll have by then. James -------------------- |
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Guest_Zvezdichko_* |
May 23 2008, 02:41 PM
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#36
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Guests |
Same here. I woke up early with a stomach pain
We all know everything will be all right, but I don't know why I'm worried |
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May 23 2008, 02:42 PM
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#37
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Member Group: Senior Member Posts: 136 Joined: 8-August 06 Member No.: 1022 |
Quotes removed. Better use the "add reply" button at the bottom of the page when replying to the previous post. Tesheiner Both MERs are travelling from west to east, so both of them are long, A is only a little bit long, B is a lot long. But surely by the mere fact of flying the MERs, we understand the aerodynamics of the shell better, and since Phoenix's shell is almost identical, if there is some systematic factor which made the MERs go long, it must be understood and modelled out of Phoenix's ellipse. I just realized that MPF also "went long", as the trajectory was from NE to SW. This may be nothing more than a coincidence, though. Different years, different atmospheric models. Beagle II may likely have gone downrange from the center of the landing ellipse, since it "landed" near in time to the MER landings. This should aid our search, somewhat. -Tim. |
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May 23 2008, 02:56 PM
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#38
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Merciless Robot Group: Admin Posts: 8785 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
What's weird is that I sweated blood before both of the MERs, and I'm actually...serene?!...for Phoenix. Now I'm worried about the fact that I ain't worried!
EDIT: Ahh, got it. After watching V1 & V2 as a kid (to say nothing of the Apollos), I trust powered landings, and am confident that Phoenix has learned all relevant lessons from MPL. -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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May 23 2008, 03:22 PM
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#39
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Founder Group: Chairman Posts: 14434 Joined: 8-February 04 Member No.: 1 |
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May 23 2008, 03:31 PM
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#40
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Member Group: Members Posts: 214 Joined: 30-December 05 Member No.: 628 |
This is what markets are good for. We can all exchange our best guesses, and we all feel a great emotional stake in the outcome. But a pecuniary stake tends to weed out the casual guessers and weight those remaining according to their confidence in a) the quality of their information and their having the experience and judgment to apply it effectively.
An outfit called Intrade has a similar market for the probability of the Google Lunar X prize being won by 2012. http://www.intrade.com It's probably not the only one. I think Lloyd's used to quote odds on a whole range of possible binary events. It's too late to do anything about Phoenix over the weekend, but maybe we should encourage the Intrade people to float a similar issue based on the successful landing of MSL. If it seems crass to think about monetary payoffs when the really important value is something like "raising the consciousness of humankind" then pledge your future proceeds to the Planetary Society! I think I'll be on the sidelines though, because my expertise is pretty much on the level of keeping my fingers crossed. Accordingly, if pressed, my best guess would have to be 50-50 with no apologies to either side. Anyway, it's just our left brains that feel compelled to quote odds about the probabilities. There is complete unanimity with respect to our hopes. 100% probability on that. tanjent |
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May 23 2008, 03:47 PM
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#41
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Senior Member Group: Members Posts: 1276 Joined: 25-November 04 Member No.: 114 |
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May 23 2008, 03:56 PM
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#42
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Senior Member Group: Members Posts: 2173 Joined: 28-December 04 From: Florida, USA Member No.: 132 |
Im so worried. Ok, but 5%? Even the most pessimistic outlook should have it at no lower than 50%. All this worry about the powered landing has me wondering how TWO Vikings ever made it to the ground in one piece, not to mention countless (by me anyway) Lunar landers -- including manned! I think powered landings are a pretty well explored territory. Heck, that last 30 seconds could well be the most sure part of the EDL sequence! I've got myself convinced anyway. |
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Guest_Zvezdichko_* |
May 23 2008, 03:59 PM
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#43
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Guests |
You are right, of course, but this technology hasn't been used for decades! A lot of people working on the projects have already retired. That's a lot of experience to lose!
Also, the pulsed thrusters. I have some worries on how they keep the spacecraft stable. |
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May 23 2008, 04:03 PM
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#44
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Senior Member Group: Members Posts: 2173 Joined: 28-December 04 From: Florida, USA Member No.: 132 |
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May 23 2008, 04:19 PM
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#45
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Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
I guess they proved themselves in all the testing... or they wouldn't be flying. For some reason this reminds me of the story of Saturn V J-2 engines that were undoubtedly tested and tested again on the ground and proved themselves robust. Then came Apollo 6 and a mysterious failure of 2 of those engines. Turns out they weren't actually tested in an environment they were meant to operate in - effectively pure vacuum and there was a design failure that only showed up in actual vacuum operation. I'm not implying something similar will happen on Phoenix, not by a long shot. It's merely an anecdote how unknown variables can always be in the hiding somewhere. There's no such thing as the ultimate test, for that you'd have to be there, fly the exact same profile as in the real thing many times and see whether any problems crop up. Everything else is just an approximation and modeling. The devil's always in the details. That said, I'm sure the Phoenix testing was quite adequate, the thing I worry the most is the actual touchdown. -------------------- |
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