Wreckage Of Beagle 2 Found? |
Wreckage Of Beagle 2 Found? |
Dec 20 2005, 01:07 AM
Post
#1
|
|
Member Group: Members Posts: 147 Joined: 3-July 04 From: Chicago, IL Member No.: 91 |
Wreckage of Beagle found scattered in Mars crater
Talk about being unlucky assuming this is confirmed. |
|
|
Guest_BruceMoomaw_* |
Dec 21 2005, 08:30 AM
Post
#2
|
Guests |
Given how close MER-A (I refuse to use that cornball name "Spirit") came to disaster because of the unexpectedly low density of Mars' upper atmosphere -- even after its hasty last-minute reprogramming to open its parachute earlier, it came within 3 seconds of opening the chute too late to avoid a crash -- I think this has an excellent chance of being the fatal flaw in Beagle: it just came down too damned fast due to the lower than predicted Martian air density, and kaplooey. We'll never know whether some additional flaw also existed that would have done it in anyway, given the flaws that the failure board found to be riddling its design -- but the air density problem by itself would have been enough, and is very likely to have happened.
I am only now coming to realize how hard it actually is to land on Mars because of its peculiar halfway nature. As Ed Strick (and Rob Manning) say, it's very hard to utilize either purely aerodynamic braking or purely rocket braking to land on it, and Mars' thin air density has a height profile such that it's difficult even to combine the two effectively enough to get the braking job done in time. We may actually have been very lucky up to now to pull off as many successful Mars landings as we have -- most of the previous failures (Mars 2, 3 and 7; Polar Lander) were due to unconnected technical problems, but Mars' atmosphere alone may seriously endanger landers, and may conceivably have done in both Mars 6 and Beagle as well as almost killing MER-A. And the bigger the lander, the more serious the problem rapidly becomes. |
|
|
Dec 21 2005, 04:40 PM
Post
#3
|
|
Senior Member Group: Members Posts: 2542 Joined: 13-September 05 Member No.: 497 |
QUOTE (BruceMoomaw @ Dec 21 2005, 12:30 AM) I am only now coming to realize how hard it actually is to land on Mars because of its peculiar halfway nature... We may actually have been very lucky up to now to pull off as many successful Mars landings as we have... I believe that Viking had pretty good margins against density variations. The best way to get margin is to have more propellant available. Much of the "difficulty" of landing on Mars comes from using a landing system like MPF/MER, which has very, very thin margins because the RAD firings happen so late in the descent and don't provide all that much delta-v. To a certain extent, the MPL/PHX system is tight because of propellant mass constraints, but I don't think those margins are nearly as tight as MER's. Is there some publically-accessible writeup about the "near-disaster" on MER? I've only heard these rumors. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
|
|
|
Lo-Fi Version | Time is now: 27th September 2024 - 12:38 AM |
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. |