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#60
by
Shuttle>CEV
on 25 Jul, 2006 22:28
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Jim - 23/7/2006 8:19 AM
Shuttle>CEV - 23/7/2006 3:32 AM
Seriously, it is going to suck when these stupid capsules are again in service. No distinction, not nearly as capable, and they WILL bite NASA in the ass. Let's enjoy these final years of the shuttle, we're gonna need it.
How will it suck?
Who cares about distinction. I hope the CEV is not reusable so they don't get names that everyone gets wrapped up about. Just serial and mission numbers would be fine. Just like the X-15.
How will they will they "bite NASA in the ass"? It is not as though the shuttle hasn't (twice). The capabilities of the shuttle have been overprescribed and not needed (except for downmass).
What are we are "gonna need"?
Remember back in the 70's when the shuttle was viewed as the be all end all spacecraft? Well, now they are doing the same thing to the CEV and they are under the impression that a capsule is somehow safer. Apollo didn't last long enough to have a major disaster, but if the program went longer, I guarantee you it would've had a disastrous loss.
Also, Columbia & Challenger could've easily been prevented, NASA had PLENTY of warnings before that and had ample time to fix them..they didn't. And no mention of the 2 Soyuz losses? But wait, that can't be, the capsule is like the greatest thing ever..*rolleyes*
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#61
by
HailColumbia
on 25 Jul, 2006 22:33
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Shuttle>CEV - 25/7/2006 6:15 PM
Also, Columbia & Challenger could've easily been prevented, NASA had PLENTY of warnings before that and had ample time to fix them..they didn't. And no mention of the 2 Soyuz losses? But wait, that can't be, the capsule is like the greatest thing ever..*rolleyes*
Logical fallacy here is that those 2 Soyuz capsules were not lost BECAUSE they were capsules.
Columbia and Challenger would have been survivable events if they were not side-mounted. If you put a winged spacecraft ON TOP then its a differant story. (although for CEV you get into some debatable issues regarding reentry at much higher velocities etc...)
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#62
by
Shuttle>CEV
on 26 Jul, 2006 00:07
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What about if your parachute fails to deploy on your capsule? You're pretty much a projectile going straight into the ground at Mach speeds, and you have no control of it like you would with a shuttle during re-entry.
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#63
by
simonbp
on 26 Jul, 2006 00:31
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Shuttle>CEV - 25/7/2006 4:54 PM
What about if your parachute fails to deploy on your capsule? You're pretty much a projectile going straight into the ground at Mach speeds, and you have no control of it like you would with a shuttle during re-entry.
Exact same as if any of the numerous hydrulic components (like the ailerons, flaps, landing gear, etc.) on the shuttle fail; the amount of single-point failures possible with a runway-landing is mind boggling...
Again, there is not real benfit to a runway landing (=wings)...
Simon
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#64
by
nacnud
on 26 Jul, 2006 00:34
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What if your APUs fail in the shuttle, your pretty much a brick from that point onwards.
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#65
by
imfan
on 26 Jul, 2006 00:35
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capsules slow down bellow M1 even before opening chutes(not that it would matter wether U hit ground in M1 or M0.5) . there are usually multiple chutes. these chutes are usually of the circle type(not sure what is the right name for it) which are very reliable.
this weekend we had a small party on airfield and I have been talking to the guy who is responsible for packing pilot chutes and he told me story from different airfield. Pilot needed to jump once and however his chute hadnt been checked and repacked for 8 years(well it is not really according to rules :-) ) and this chute had been used for all that 8 years(during which may people sit on that, the chute had been brought many times from plane to store and back)... this chute opened
thats for chute reliabily and I am sure chutes at NASA will get much more care
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#66
by
Norm Hartnett
on 26 Jul, 2006 01:12
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I am not particularly knowledgable about these things but I ran across this :
"One of the really scary things about NASA's CEV plans for lunar exploration is that they plan to use the same aerodynamic skip technique developed by the Russians in the 1960's to return to US territory after a re-entry over the south pole. The problem with this approach is how you recover the capsule in the vast southern oceans if the guidance fails and it has to make a ballistic re-entry at the first entry interface. This preoccupied Russian planners a lot in the 1960's, leading to enormous estimates for the size of the naval and airborne recovery forces that would have to be arrayed along the re-entry path stretching a quarter of the way across the earth through the most remote oceans imaginable."
Here
http://astronautix.com/Mambo/ - 2006/05/26 Sounds spooky to me. Is there anyone that can address this?
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#67
by
Shuttle>CEV
on 26 Jul, 2006 01:38
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simonbp - 25/7/2006 7:18 PM
Shuttle>CEV - 25/7/2006 4:54 PM
What about if your parachute fails to deploy on your capsule? You're pretty much a projectile going straight into the ground at Mach speeds, and you have no control of it like you would with a shuttle during re-entry.
Exact same as if any of the numerous hydrulic components (like the ailerons, flaps, landing gear, etc.) on the shuttle fail; the amount of single-point failures possible with a runway-landing is mind boggling...
Again, there is not real benfit to a runway landing (=wings)...
Simon
Yes, but once you reach a certain speed, you can bail out of the shuttle. How do you get out of a capsule?
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#68
by
Jim
on 26 Jul, 2006 01:50
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No need to bailout, back up parachutes. Bail out of the shuttle only works under Mach 1. A capsule is safer. there are less parts, better abort scenarios, easier TPS, passive entry (or something close to it).
Response to earlier post: the CEV does have a manuvering entry. If the control system fails, then it has a ballistic entry. Shuttle does not have a backup to RCS, APU, HYD failure
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#69
by
Jackson
on 26 Jul, 2006 02:21
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I think that's something that some of us younger readers worry about, paracutes. We're so used to a winged lifting body being there and getting them home. Dropping and hoping the paracutes open scares me, but I assume these things don't fail historically like on the Soyuz and back ups are good (actually didn't know about that).
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#70
by
HailColumbia
on 26 Jul, 2006 02:38
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one problem with a capsule, if you want more interior space, you need to make it wider, which means a wider booster. other shapes you can make LONGER.
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#71
by
zinfab
on 26 Jul, 2006 03:44
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Hail, both would require a new vehicle. elongating a capsul into a cylinder/capsule is as easy as making a winged body longer.
some things are simply shaped for a very good reason.
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#72
by
HailColumbia
on 26 Jul, 2006 03:51
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well I was more talking about the "apollo" shape, as it is the rule for the CEV.
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#73
by
lmike
on 26 Jul, 2006 05:15
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HailColumbia - 25/7/2006 7:25 PM
one problem with a capsule, if you want more interior space, you need to make it wider, which means a wider booster. other shapes you can make LONGER.
Longer, especially high L/D bodies would only allow for side-mount (CG placement, ascent control issues if top-monted with no shroud) which in turn would disable abort modes, preclude use of externally insulated cryo stages, complicate stacking, be more expensive and labor intensive. It's a catch-22. With current propulsion methods high l/d is a pain in the rear during ascent as well. To solve this you need to go horizontal take-off as well. Which in turn swings back to basic propulsion (rockets are more efficient taking off vertical)
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#74
by
Jim
on 26 Jul, 2006 11:13
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HailColumbia - 25/7/2006 10:25 PM
one problem with a capsule, if you want more interior space, you need to make it wider, which means a wider booster. other shapes you can make LONGER.
There is no rule that says a capsule can't be wider than the launch vehicle. Payload fairings more times that not are wider that the LV.
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#75
by
CuddlyRocket
on 26 Jul, 2006 11:52
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Lots of small planes (with wings, and even engines) have parachutes nowadays - to land the plane safely if anything goes wrong. They save lives. Parachutes are a reliable and safe system.
Sure, they can go wrong. What can't? But, it's a question of probabilities, and the probability of a fatal failure is lower for parachutes.
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#76
by
Martin FL
on 26 Jul, 2006 12:09
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A soyuz paracute did fail once I remember. Killed all on board.
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#77
by
Jim
on 26 Jul, 2006 12:11
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Martin FL - 26/7/2006 7:56 AM
A soyuz paracute did fail once I remember. Killed all on board.
Bad design hurried into production and into flight
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#78
by
imfan
on 26 Jul, 2006 15:36
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Martin FL - 26/7/2006 1:56 PM
A soyuz paracute did fail once I remember. Killed all on board.
it was soyuz 1 . in this case it means that there was only Vladimir Komarov onboard. Killed all is quite misleading. that flight was prepared in a great hurry under political preasure. whole flight experienced lot of trouble. I think those chutes failed because they werent preheated because lack of power which was consequence to solar panel deployment failure
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#79
by
zerm
on 26 Jul, 2006 15:36
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For a really good detailed explanation of the Soyuz failure (and BTW- "all" aboard was a single cosmonaut) read Alexi Leonov's take on it in "Two Sides of the Moon" by Toomey. It is the side-by-side stories of Dave Scott and Leonov and although both men's stories are terrific- Leonov's accounts of what went on on the other side are really great and highly detailed.
IMO- These arguments against the CEV in favor of some space plane that is not even close to development are really shot sighted. It seems that every time I read one it can be replaced with "bring back the Dyan Soar" and "My favored vehicle will have a zero failure rate" not to mention the fact that they seem to believe political (i.e. FUNDING) winds will always blow favorably- even in the gap. CEV critics also seem to think that no government contractor will ever run over budget. When the fact is that rarely do government contracts not overrun their budget. Can you imagine where we'd be if these same critics had watched the Grumman contract on the LEM under the same microscope as they watch the CEV?
Here's my take on it- The CEV is going to keep us flying in space... PERIOD! And so far as "The Vision" goes, remember that, other than those few people who have hands-on the tip of the arrow of space exploration, for the public and humanity at large, spaceflight is more about inspiration than exploration. That is it's true value.
