Discussion A contingency plan for fast return of the U.S. to space.

[Hlynkacg]

Vladimir Titov and Gennady Strekalov would also serve as arguments for effective launch escape.

Agreed, but that doesn't change the fact that it still belongs in the "nice to have" column vice the "absolutely required" column.

You're right. After those poor devils perished, NASA installed a fully functional launch escape system in the shuttle....

:ninja:'ed

 

[Andy44]

I'm not trying to be an internet jerk, Urwumpe has a point, but the fact is that if NASA really really really needed to launch people into space on short notice SpaceX and Boeing would both be able to do it pretty quick, provided you give them enough money and are willing to buy off on the risk of an abbreviated testing program including an untested LES. The tech and the know-how are there.

I'm not saying it would be smart, of course.

 

[Star Voyager]

Besides, astronauts are aware of the risks involved and send in their application anyway. Even of they are selected for a mission, they could decline if they weren't comfortable with any aspect of the mission.

 

[Andy44]

Besides, astronauts are aware of the risks involved and send in their application anyway. Even of they are selected for a mission, they could decline if they weren't comfortable with any aspect of the mission.

Yes, but it's not ethical to take advantage of an astronaut's willingness to fly at any cost, so you have to be careful. The prestige of being an astronaut can drive people to take unreasonable risks.

 

[Urwumpe]

I'm not trying to be an internet jerk, Urwumpe has a point, but the fact is that if NASA really really really needed to launch people into space on short notice SpaceX and Boeing would both be able to do it pretty quick, provided you give them enough money and are willing to buy off on the risk of an abbreviated testing program including an untested LES. The tech and the know-how are there.

I'm not saying it would be smart, of course.

The problem is also that we are all here watching the world through the spaceflight fans eyes. Do we need people in space at all and at all costs? Sure? For what? *

Unless we need to do a rescue mission to get those astronauts home, that are already in space, we have no urgency there, no need to give a private company our money. National pride is not a reason to risk the lives of others. And if national pride is an argument by Elon Musk, he may spend his own money on the accelerated program for his own national pride.

And about the need for LES: The shuttle never got a LES, because its configuration was badly suited for one. Apollo and Gemini had different kinds of LES, but it still meant about 50 seconds of flight without a chance to use any version.

But that is getting different, if you plan for Space tourism as well. Then you not only need reliable robust launch escape systems, but also one that works so smooth, that you don't nearly kill your passengers.

Also, I can make you a promise: Murphy's law about spaceflight will also apply to spacecraft sold by somebody with a massive Reality Distortion Field - if you have no LES, you will get into a situation where you will badly miss it.

* While I think that we should have more manned spaceflight and more astronautic science - I don't think it is so important that it can't wait a few years for a proper solution.

 

[kamaz]

All that is academic. If there is a political will to fly a mission, it will fly, LES or no LES. If there is political will, the mission will even fly outside of the vehicle spec (STS-51L).

 

[Hlynkacg]

Also, I can make you a promise: Murphy's law about spaceflight will also apply to spacecraft sold by somebody with a massive Reality Distortion Field - if you have no LES, you will get into a situation where you will badly miss it.

Yes, and airliners occasionally crash, but you don't insist on wearing a parachute and O2 mask everytime you board a 747 do you?

Cost/benefit is everything, do we, or rather does NASA care enough about space exploration to accept the risks associated with it?

If no then why bother?

If yes then we need to be objective about what those costs actually entail and what those risks really are. The STS was horribly unsafe yet we flew it anyway, thus the lower bound for acceptable safety margin has been established.

So long as crewed Dragon, Dreamchaser, or CST kills less than 4% of it's passengers it will still be an improvement on the Shuttle's record.

 

[Urwumpe]

Yes, and airliners occasionally crash, but you don't insist on wearing a parachute and O2 mask everytime you board a 747 do you?

We also don't consider a rate of 2 deadly accidents among 100 flights of a 747 as normal there (Which would be about one such accident every 6 hours). Also ETOPS and other safety standards also exist among aircraft, I don't see people complain about such safety standards delaying aircraft development.

 

[Hlynkacg]

We also don't consider a rate of 2 deadly accidents among 100 flights of a 747 as normal there

That's kind of my point, so long as a spacecraft or launch vehicle maintains that rate or less, any complaints about it being "unsafe" are obviously emotional rather than objective.

Assuming that the STS's accident represent the "acceptable" maximum, a 2% chance of death each flight is "safe enough".

 

[N_Molson]

Yes, and airliners occasionally crash, but you don't insist on wearing a parachute and O2 mask everytime you board a 747 do you?

As says the hostess, in case of depressurization (I always love how kindly they say that), an oxygen mask will fall right in front of you.

What they don't say is that you have only 10-12 minutes of O2 but well, much better than nothing.

And, provided there are no "dangerous" parts inside and that it can fit in the cabin luggage format, I think nothing prevents you to carry your own parachute :bailout:

Something tells me that it would require advanced technology materials to fit the size and mass constraints but that's certainly not undoable...

Back to the topic, launch a capsule nowadays without a functional LES is out of question. In the history of manned spaceflight, it was done only with Voskhod 1 & 2, and that was stupidly dangerous. Nikita Khruchev was very very lucky that nobody died during those two flights, and even more that Alexei Lenov performed and survived the EVA.

Now yes, there is the Shuttle case, which had a 'gap' in the abort sequences. The interesting fact is that, even if the cabin could have been separated and boosted away when the Challenger disaster happened, that would probably not have helped. The SRB toric joint failure was unoticed by sensors and even cameras until the disaster happened. Say they had put an Apollo capsule with a LES tower on top of the STS instead of the Shuttle on the side, would the crew had been saved ? Maybe, maybe not... But if the flame getting out of the SRB had been noticed, it would have let enough time to shut down the SSMEs and detach the Shuttle, no ? So the crew would have had a chance to land or bail out. So, I'd say it was more an instrumentation problem. Columbia was a basically a thermic shielding failure, and capsules can nothing against that either. The difference is that it is much easier to make sure that the shield is in perfect shape before launch, and also the fact that it is safely encased until the re-entry capsule is separated.

 

[ISProgram]

You're right. After those poor devils perished, NASA installed a fully functional launch escape system in the shuttle....not.

At least they were sensible enough to test it... :lol:

[ame="http://www.youtube.com/watch?v=dfVTX25hH-I&feature"]Crew Escape Certification Test - YouTube[/ame]

 

[Hlynkacg]

Back to the topic, launch a capsule nowadays without a functional LES is out of question.

What everybody seems to have trouble understanding is that the presence of an LES is largely irrelevant.

The ONLY metric that matters in any discussion of safety is the probability of mishap (serious injury or death). If that probability is within acceptable bounds additional sub-systems represent unnecessary cost and complexity.

 

[Fabri91]

Exactly: what matters is the probability of serious injury/death.

With modern launchers it appears that a catastrophic failure during launch could reasonably happen once every 100-200 launches, being generous with the odds, which is completely unreasonable.

Adding a LES system reduces the possibility of serious injury/death by providing an abort option even during the initial boost phase.
Of course the LES has to be as simple and reliable as possible, but what is important to consider is that, at worst, it doesn't worsen the odds for the crew's survival.

 

[Hlynkacg]

With modern launchers it appears that a catastrophic failure during launch could reasonably happen once every 100-200 launches

Well yes, but we've also established that this is within the acceptable bounds of an LV without LES. Afterall, if it weren't the remaining STSs would have been scrapped post Challenger.

The question thus becomes does the added cost and complexity of an LES outweigh the likely benefits. There is such a thing as diminishing returns you know.

 

[Urwumpe]

The question thus becomes does the added cost and complexity of an LES outweigh the likely benefits. There is such a thing as diminishing returns you know.

You know what will happen. SpaceX builds a capsule without tested LES. Boeing waits for the wrong government decision towards SpaceX and sues the USA for tolerating the lack of that feature despite a capsule existing that shows that it is possible. The rest goes on for a few years. Maybe somebody wins, maybe all lose.

 

[Hlynkacg]

You know what will happen. SpaceX builds a capsule without tested LES. Boeing waits for the wrong government decision towards SpaceX and sues the USA for tolerating the lack of that feature despite a capsule existing that shows that it is possible. The rest goes on for a few years. Maybe somebody wins, maybe all lose.

At which point SpaceX sues Boeing over the 787's lack of ejector seats.

 

[Urwumpe]

At which point SpaceX sues Boeing over the 787's lack of ejector seats.

And then Facebook buys SpaceX.... :facepalm:

 

[RGClark]

I seem to recall the goal for Ares I was to put it at better than 10 times safer than the shuttle, which would put it in the 1/500 to 1/1000 failure rate range. There was alot of debate on whether the final design would have reached that goal.
But that seems to be reasonable goal to aim for for manned flights.

Bob Clark

 

[Urwumpe]

I seem to recall the goal for Ares I was to put it at better than 10 times safer than the shuttle, which would put it in the 1/500 to 1/1000 failure rate range. There was alot of debate on whether the final design would have reached that goal.
But that seems to be reasonable goal to aim for for manned flights.

Bob Clark

This includes also the LES in the equation. And was not achieved at the PDR. The simulations for a case burst scenario had not been that favorable even with a LES.

 

[garyw]

You mean like they "tested" the shuttle before sticking two guys in it and launching it into space?

No. Nothing at all like that, in fact the absolute opposite of that.

You're right. After those poor devils perished, NASA installed a fully functional launch escape system in the shuttle....not.

Of course not. The work involved would have killed the American space programme right there and then.