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John Hoare posted:

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Unfortunately scientists and engineers have become to comfortable with the fact that if you apply enough force a brick will fly. Such a solution is both inelegant and prone to disaster, just look at the American shuttle program.

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I would not consider the space shuttle a "disaster" or "inelegant" at all, and neither would most who follow the various space programs. 115 flights and only two failures (98.3% success rate) is actually pretty good for a launch vehicle (one of the top rates in the history of active launch vehicles). The Space Shuttle has functioned pretty much the way it was designed to. To get a space vehicle of the shuttle's size and weight to launch like a rocket, carry a very large payload, operate in low-earth orbit, and then land like a glider to be re-used is a remarkable feat, and is a tribute to the engineers and technicians who designed, built, and launch the shuttle.

However, is the shuttle cost effective? Not really, as there are less expensive somewhat simpler (and potentially a little less dangerous) ways of getting things into space. Thus, as a "cost saving" item, it definitely did not live up to its advance billing at all (which is why its days are numbered). The expendable series of rockets both active and planned will probably be better on the pocketbook, but the space shuttle does deserve a high regard as a remarkable technical achievement in the history of space travel. Clear skies to you.

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David, I don't think that the Space Shuttle program is a disaster, I simply said that it is disaster prone. To lose two crews out of 115 missions means that there were 2 disasters, which is enough to justify labelling a process disaster prone. If it were in any other line of business the local health and safety agencies would close NASA manned operations down for good. Having said that, the program is less disaster prone than most because the average failure rate for space missions is about 1 in 20.

As for elegance, well, it is purely a matter of opinion. I don't consider systems that have to expend a significant proportion of their fuel/energy payload just to get off the ground elegant. Rocketry is brute force and there is nothing elegant about it. It's the 20th century way of doing things and it's about time that we came up with something better, not to mention safer.

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John
Watery Glebe
Puddlestown
Co. Kildare

Chaos is the rule of nature
Order is the dream of man
Henry Brooks Adams

IFAS

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I think that one of the toughest challenges is in the field of space medicine: how to sustain a healthy human in a low gravity or gravityless environment for such a long time that would require the round trip plus wait time in Mars for the return window. I don't think that the current record of time in space nearly approaches such demands.

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I think that one of the toughest challenges is in the field of space medicine: how to sustain a healthy human in a low gravity or gravityless environment for such a long time that would require the round trip plus wait time in Mars for the return window. I don't think that the current record of time in space nearly approaches such demands.

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I agree. It's the principle reason that I believe our biggest effort should go into finding a new means of propulsion capable of providing a sustained 10m/s^2 at a reasonable payload cost. If we could get around the system by constant acceleration/decelleration maintaining human health in low gravity would only be a problem for missions that land on low gravity bodies or spend significant amounts of time in orbit. The massively reduced journey times would also produce benefits by reducing the amount of time for which travellers would be exposed to harmful radiation.

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Not only health problems of weightlessness. Unless you use the constant accelleration/decelleration setup, you're going to have a significant supply problem to solve. (Mars mission I'm referring to here) So you send supply "pods" up ahead of time. Uh oh, missed the rondevous by just "that much". Uh, how much oxy/water did you say we have?????
And a 2,3, or 4 manpower mission ain't gonna cut it. There will be a lot of simple physical work to do, just to keep things going. I figure a minimum of 6 to 10 bodies... That's lotsa groceries over a couple of years....
Hubert

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www.smoggybottom.org

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John Hoare posted:

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Unfortunately scientists and engineers have become to comfortable with the fact that if you apply enough force a brick will fly. Such a solution is both inelegant and prone to disaster, just look at the American shuttle program.

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I would not consider the space shuttle a "disaster" or "inelegant" at all, and neither would most who follow the various space programs. 115 flights and only two failures (98.3% success rate) is actually pretty good for a launch vehicle (one of the top rates in the history of active launch vehicles). The Space Shuttle has functioned pretty much the way it was designed to. To get a space vehicle of the shuttle's size and weight to launch like a rocket, carry a very large payload, operate in low-earth orbit, and then land like a glider to be re-used is a remarkable feat, and is a tribute to the engineers and technicians who designed, built, and launch the shuttle.

However, is the shuttle cost effective? Not really, as there are less expensive somewhat simpler (and potentially a little less dangerous) ways of getting things into space. Thus, as a "cost saving" item, it definitely did not live up to its advance billing at all (which is why its days are numbered). The expendable series of rockets both active and planned will probably be better on the pocketbook, but the space shuttle does deserve a high regard as a remarkable technical achievement in the history of space travel. Clear skies to you.

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David, I don't think that the Space Shuttle program is a disaster, I simply said that it is disaster prone. To lose two crews out of 115 missions means that there were 2 disasters, which is enough to justify labelling a process disaster prone. If it were in any other line of business the local health and safety agencies would close NASA manned operations down for good. Having said that, the program is less disaster prone than most because the average failure rate for space missions is about 1 in 20.

As for elegance, well, it is purely a matter of opinion. I don't consider systems that have to expend a significant proportion of their fuel/energy payload just to get off the ground elegant. Rocketry is brute force and there is nothing elegant about it. It's the 20th century way of doing things and it's about time that we came up with something better, not to mention safer.

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I disagree… Challenger was a failure of leadership and management NASA had never tested the shuttle hardware at the temperatures that the launch took place at.

Challenger should have never left the pad.

Columbia was just bad luck. They knew about the foam but had never realized the danger of it. It is easy to point out the errors after the tragedy has happened.

Lastly, people forget the failure rates that NASA purposed back when the Shuttle first started flying. We have gotten use to "no serious failures" and we have forgotten how dangerous spaceflight is.

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Preston



Celestron 11" Nexstar GPS XLT
Lunt LS60T/Ha 60mm f/8.33 (on order)

It’s not finishing something when your tank is empty that makes you a stronger person. It’s brushing yourself off and refacing the foe that defeated you with the same determination and willingness to fight that you had when you began your journey.

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Columbia was just bad luck. They knew about the foam but had never realized the danger of it. It is easy to point out the errors after the tragedy has happened.

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The error that was unforgivably arrogant was the intervention by someone up the chain of command *against* permitting ground-crew engineers to request US Intelligence agencies (particularly within DOD) to use their advanced surveillance capabilities to try to capture images of the shuttle to check for possible signs of damage.

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I lived close to the Cape for the first shuttle launch, and a few days after the launch, a local paper ran a story about another local DOD facility using their big scope to look at the bottom of the shuttle while it was in orbit to check for missing tiles.

I'd heard a while after that, that the DOD was not pleased that the story ended up in the papers.

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Mike
N8/CG-5/40D
Coming sometime/Maybe FrankenRebel


Edited by LivingNDixie (08/15/06 06:04 PM)

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Talk about new fuels... How about Diet Coke and Mentos?

If everyone is confused, google it. I also saw it this week on Mythbusters.

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I caught some of that. I had to stop just after they said the power wasn't solely due to the CO2. What was the other accelerant? Wish I'd known that as a kid, would've really sent my Alpha 1 way up there.

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The error that was unforgivably arrogant was the intervention by someone up the chain of command *against* permitting ground-crew engineers to request US Intelligence agencies (particularly within DOD) to use their advanced surveillance capabilities to try to capture images of the shuttle to check for possible signs of damage. Also, didn't some large-aperture amateur astronomer who tracked the shuttle with his scope one night during orbit (and had done so with previous flights) notice an anomoly about the leading edge of the left wing? [I seem to remember there being a grainy CCD image he took, could be wrong about that] - didn't he try to contact authorities about that? OK, I can understand the "pros" in NASA being disinclined to give much attention to warnings raised by outside amateurs - probably inclined to think very few know what they're talking about and that many of them are cranks besides. I can also understand it being forgivable error if NASA had taken advantage of our intelligence imaging capabilities to investigate, and had it turned up inconclusive to have hopefully assumed nothing was wrong. But the stupid arrogance of the superiors who overruled even attempting to use such is unforgivable.

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Hindsight is indeed 20/20, but I wouldn't put too much criticism on those who didn't exactly authorize a look with the DOD assets. There wasn't really any clear indication from the ascent videos and stills that damage had occurred, although in hindsight, it would have been better to have had some images taken to make certain that things were OK for entry. Indeed, it is possible that the damage was slight enough in areal extent that even if an on-orbit image had been taken, the RCC panel damage may or may not have shown up conclusively. Several ground-based images were done with tracking cameras, but only the payload bay side of the shuttle was clearly seen without a clear shot of the wing section which was hit. On entry, the panels were then subjected to the mechanical and thermal stress of reentry and would have then failed completely with the results we have seen. No amateur video was taken that shows the damaged wing clearly, but a Starfire (Air Force) infrared tracking camera *does* show indications of wing leading edge damage as the shuttle flew over during reentry. All we know for certain is that a large chunk of foam damaged the RCC panel enough that it was unable to protect the wing from heating damage during reentry, leading to the loss of the vehicle and crew. It would have been best to have a more robust thermal protection system (or a shuttle version which was smaller and launchable on top of a large expendable booster), but that is not what the "compromise" that lead to the final shuttle design arrived at. Clear skies to you.

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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info

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