Thinking Beyond the Only-Chance Landing

Status
Not open for further replies.
S

SpaceForAReason

Guest
When I was a kid, I first heard the account of the brave/stupid men that would put themselves in a padded barrel and go over Niagra Falls. I admired their daring. I was shocked by their stupidity. Once in the river they were committed to the plunge, successful or not. There was no way to abort the attemt once they were committed. All of them were convinced that they had planned sufficiently to survive the fall. Many died. The practice is now illegal for the obvious reasons.

I was reading some of the threads and thinking of all the advances we have made over the years and how we still have one of the biggest problems still facing us: How to handle a landing (or launch) that has gone wrong.

If the Space Shuttle were to be in a "commit-to-land" status (and I would also say you are committed to land if your spaceship will not reach orbit) and needed to divert or abort, could it? Now, thinking ahead, if a capsule were in a "commit-to-land" status and needed to divert or abort, could it? (I don't want to land in unfriendly territory either. A bit of control would be nice.)

When astronauts return from orbit, they are relatively helpless. They do not possess the ability to return to orbit if something goes wrong. There is no 'safe-eject' system. They do not possess the ability to perform a landing abort to fly around for a second try. They cannot divert or abort once they are committed to land. They have one chance.

A number of years ago I was on a connecting flight from Dallas/Fort-Worth to Shreveport. The weather at Shreveport was rainy with thunderstoms in the area. The jet was cleared for departure and left DFW heading toward Shreveport and the bad weather. The pilot was obviously confident in the fact that no matter what the situation, a successful landing could be made. As we neared the destination, buffeted by turbulence and frequently lit by the relatively close lightning, it became apparent that a 'safe' landing would not be possible at Shreveport. The decision was made to divert to the airport in Monroe, LA. The only inconvenience was an two-hour bus ride. Believe me, I was still thankful not to be sitting in DFW waiting for the weather to clear as I still had a schedule to keep. Time is money.

What can we do better to improve our ability to commit to a landing and have it work even if we have to divert or abort the attempt?

Escape towers work fine on launches where the first stage can be shut-down. It does not work so well when it is at the top of a raging roman candle that won't turn off (SRB/Ares I). The roman candle wins the F=ma battle every time unless the little escape tower can out-muscle it; is that likely? :shock:

High altitude para-gliders, vehicle thermal airbags, powered abort systems, ejectable cockpits like the X-15 that can survive vehicle destruction? :?:

What do you think? Is there something we can do about it? Does it matter?
 
S

SpaceForAReason

Guest
Thanks! That was a very interesting read.

It would seem that we can handle some very specific abort situations with confidence, but we have yet to be able to handle all situations... interesting. The type of vehicle seems to play a very large role in how well it can abort. What was presented indicated that a capsule is the safest vehicle when aborting from the top of a rocket. It was very difficult for the Shuttle to even get what few safe aborts it has. Re-entry had a whole new set of problems.

Thanks for the information.
 
K

kelvinzero

Guest
SpaceForAReason":3bh0hmzw said:
Escape towers work fine on launches where the first stage can be shut-down. It does not work so well when it is at the top of a raging roman candle that won't turn off (SRB/Ares I). The roman candle wins the F=ma battle every time unless the little escape tower can out-muscle it; is that likely? :shock:

I think the little escape tower can apply much higher acceleration. It is only lifting the crew module, not the crew module plus the second stage and the first stage. Also it only needs to apply this acceleration for a much shorter time. Also rocket launches are something like 3-5 g so humans can handle them for a few minutes. For shorter periods humans can survive much higher values, and some injury is acceptable if it saves your life.

Also (and this is just a guess) outrunning an SRB might be more plausible than outrunning the detonation of a hundred tons of liquid oxygen and hydrogen.
 
V

vulture4

Guest
If you think you can outrun the explosion of an SRB just watch the video of the 1998 Delta explosion, which resulted from failure of a relatively small SRB; one second the rocket is flying normally, the next it's a fireball. The LAS on the Ares had to be extremely large and powerful, with an acceleration of over 20G. Even then it was not guaranteed.

The Shuttle can already weather divert or simply delay entry if the weather is bad, and it has an autoland system that would work in zero visibility if we can just get someone to test it. What would an airliner do if it suffered a major guidance or control failure? Answer: break up in flight. No parachutes, no ejection seats, no survivors. This happens every few years but is very rare on a per-flight basis. I do not know of any way to add a practical escape system to an airliner or any aircraft cruising at over 400kph. Does that bother you? Probably not, because the system is reasonably safe. We need operational procedures where appropriate, such as an alternate landing site for severe weather. But systems failures in the vehicle need to be eliminated by reliable components and thorough testing, not layers of redundancy that make the vehicle too heavy and costly to fly or emergency procedures that may or may not work in a real, and thus unanticipated, emergency. My pet peeve is the launch abort system, which people (including, apparently, some astronauts) see as eliminating all or most risk. In reality escape systems protect only against failures that can be anticipated in advance, and any failure mode that is understood and anticipated can and should be eliminated in the basic design. not escaped at the last second with equipment and procedures that may or may not work.
 
P

Polishguy

Guest
If you want to improve the landing profile of a lifting body or space plane, the solution is simple.

Back when the Russians built Buran, they built it to be capable of retrofit with jet engines for a powered landing. That sort of thing on a Shuttle could make it capable of changing landing location in flight.
 
E

EarthlingX

Guest
If i remember correctly, they were flying it with jet engines, like in the air, not much presentation.
 
E

EarthlingX

Guest
kelvinzero":3r8yisaa said:
[youtube]http://www.youtube.com/watch?v=gL1xUWgBlFw[/youtube]

cool :)
Very :cool:

Just as long as no-one is hurt and insurance covers the landing ..
 
Status
Not open for further replies.

Latest posts