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Short sighted attitudes toward escape/emergency egress

Posted by: Guest - Thu Apr 08, 2004 2:32 pm
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Short sighted attitudes toward escape/emergency egress 
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Post Short sighted attitudes toward escape/emergency egress   Posted on: Thu Apr 08, 2004 2:32 pm
If a project can't afford to buy a Russian K-36 seat then maybe they should consider whether they have enough money to do what they want in the first place.

Over 20 years ago a Russian pilot survived with no significant injury ejecting from a Mig-25 doing Mach 2.8 at 60,000 feet.

The X-15 seat was rated up to Mach 4 and up to 120,000 feet.

Joe Kittinger verified in 1960 a bailout parachute system for altitudes of over 100,000 feet.

Colonel John Stapp verified in 1952 that human beings can survive the g-forces of supersonic ejection.


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Post Shuttle   Posted on: Sat Apr 10, 2004 1:15 am
An escape mechanism? You mean like the space shuttle has?


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Post    Posted on: Sat Apr 10, 2004 6:07 pm
that was a cheap shot. the shuttle SHOULD have had one too.


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Post    Posted on: Sat Apr 10, 2004 6:57 pm
zinfab wrote:
that was a cheap shot. the shuttle SHOULD have had one too.


There is nothing cheap about it when it costs seven lives. :cry:

More to the point, safety is process which requires flexibility of attitudes. The fact that this is not easily accomplished within a bureaucratic environment such as NASA is precisely why private competition with multiple development paths are so important.

For example, should there be escape/emergency egress systems?

Maybe yes. Maybe no. It depends on any number of factors from weight and performance issues to risk avoidance issues to business survival after a failure issues.

Just as the prime law of investing is "Don't put all of your eggs in one basket" (Think ENRON), any new endevour should be diversified, so that one failure does not destroy all of the eggs.

In other words, who has their eggs in one basket? The 27 teams of the XPRIZE competition or NASA? :D

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Post    Posted on: Sat Apr 10, 2004 8:22 pm
As near as I can see Egress systems are a really bad idea for space vehicles.

That needs to happen is for the crew cabin to be designed to survive the rest of the rocket exploding. If the rocket explodes at any altitude the crew cabin comes back in one piece without needing to be "ejected" manually or anything.

The Space shuttle cabins almost survived both disasters. They need adjustment and big parachutes and 14 astronauts would still be with Nasa. They are already made nearly entirely of RCC so they survive re-entry.

Just a thought. I wouldn;t want to bail out in orbit or during re-entry is all.

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Post    Posted on: Sun Apr 11, 2004 1:07 am
zinfab wrote:
that was a cheap shot. the shuttle SHOULD have had one too.


Not a cheap shot. NASA is spending thousand of times more than the x-prize competition, an has elected not to have an ejection scheme. The x-prizers are also going the no eject route (as far as I knw), and ashould no be criticized for it.

It is basic logic, not a cheap shot.


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Post    Posted on: Sun Apr 11, 2004 1:45 am
the real reason they don't have an escape system isn't cost as much as it is the fact that it wouldn't do much good in the environments where it would most likely be needed IF the vehicle was designed well in the first place. challenger is a place where it would have helped, but challenger shouldn't have happened if nasa had been appropriately saftey concious in the first place. colombia..... i have a hard time seeing any escape system other than maybe something that boosted the capsule back up to orbit where it could reenter again as saving them simply because of the speed at which the shuttle exploded. again, that disaster wouldn't have happened if a few basic precautions were taken, though admittedly they would have been much harder to do than the challenger ones would have been. a well built space vehicle will most likely need the escape systems in the place it spends the most time-- space. aside from the standard sci-fi escape pod, there really isn't a good way to survive a space-based disaster other than trying to ride it out.

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Post "I don't have an anger problem. I have an idiot problem   Posted on: Mon Apr 12, 2004 12:58 pm
"For example, should there be escape/emergency egress systems? Maybe yes. Maybe no. It depends on any number of factors from weight and performance issues to risk avoidance issues to business survival after a failure issues."

Every damn time somebody says an environment is "unsurvivable" or an escape system would be "too much weight", well guess what? When the engineers actually analyze it in depth they discover the enviroment IS survivable and the weight IS tolerable.


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Post    Posted on: Mon Apr 12, 2004 1:28 pm
And That is a decision every engineering team needs to make from themselves. Keep smiling. :D

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Post    Posted on: Mon Apr 12, 2004 9:30 pm
They Crew Cabin should be a near impervious "escape pod". Think of an RCC Sphere, with parachutes and possibly airbags. The same design would be scalable to a whole range of flight systems with a bit of thought to intergration systems.

Serious problems are harder to come by in space. Outside of a thruster going completely spastic there is not a lot that can kill you for sure. Without propellants, of planets to run into it seems most stuff is just uncomfortable. You can set your space station on fire and live through it. The worst stuff all involves venting or thrusting in an odd way that sends you back towards the atmosphere and that buts you back at "in aptmosphere" difficulties. So you are back to having a section that will surivive re-entry with parachutes or whatnot. At the moment that means a soyuz "escape" vehicle.

The space shuttle cannot carry a soyuz in the boot on every flight. But it has got a bullet proof nose cone...

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Post    Posted on: Sat Jun 19, 2004 4:55 pm
Some X-Prize projects, like the Canadian Arrow, have emergency solid-rockets attached to the cabin in case anything goes wrong from launch
to stratospheric altitudes.
BUT!....aside from safety issues, there's extra benefits with having
those emergency SRs attached to the cabin: By using the main liquid-fueled rocket motor to get to 100 kilometers altitude, then by igniting
the emergency solid-rockets after the liquid-fueled rocket motor has done its job, the peak altitude can be much HIGHER, perhaps over 160 kilometers
[100 miles up +]
Almost as high as Shepherd flew in 1961.

Jacob


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Post    Posted on: Sat Jun 19, 2004 5:04 pm
You cannot eject at supersonic speeds with anything better than a 50/50 chance of survival. I am afraid that nobody ejected at mach 2.8 from a Foxbat and survived. That is why aircraft that are designed to operate at these speeds like the old F-111 had an ejectable crew compartment. Of the one person I have heard of who survived a supersonic bail out from an F-15, his shins were snapped in half and his arm was hanging on by its skin due to the wind blast. The man in the back seat did not make it unfortunately. I believe that Idiom has got exactly the right idea on this subject.

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Post X Prize vehicle bailout   Posted on: Sun Jun 20, 2004 9:00 am
I don't know if such a fancy ejection seat is really necessary. Why would you ever want to eject at such high altitude and high speed? As long as your vehicle is more-or-less intact (even if damaged so badly that it can't land) you would want to stay inside until it reentry is over. After that you would be bailing out in the sensible atmosphere from a vehicle falling at a not-too-high terminal velocity.

If the propulsion system fails spectacularly enough to damage the vehicle so it can't survive reentry it will probably kill you instantly. If it doesn't you would want to stay inside until reentry is over.

Problems during the boost phase are more serious if it fails shortly after liftoff. Air launching has a distinct advantage here because it gives you much more time to deal with the problem.


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Post    Posted on: Mon Jun 21, 2004 4:17 pm
How many 747's have ejection systems ;)


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Post    Posted on: Mon Jun 21, 2004 6:22 pm
But do you need ejection seats, or emergency solid-rockets attached
to the astronaut-cabin?
The Canadian Arrow has emergency solid-rockets beneath the cabin.

LOOK!...People are going to die regardless of how many safety features you put on a vehicle.
The vehicle can be a car; people still die in car wrecks.
The vehicle can be an aircraft; people still die in aircraft crashes.

PLEASE!!~...TELL ME!!....How much safety do you want?


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