5 ms·

I know SpaceX is looking to make space flight more like commercial flight. Given that commercial airliners don't have anything like this in their design, should

by burd691 11y ago

I know SpaceX is looking to make space flight more like commercial flight. Given that commercial airliners don't have anything like this in their design, shouldn't the goal be to get space flight to the same failure rate as commercial flight? Thus eliminating the need for an abort system?

cyrus_ 11y ago
Once they are that reliable, I'm sure SpaceX could consider removing the abort system to save on weight. Though I assume that the SuperDracos are designed to also be used in space / on Mars.
- greglindahl 11y ago
  And for landing back on Earth, just not initially: http://www.spacex.com/news/2014/05/30/dragon-v2-spacexs-next-generation-manned-spacecraft http://www.spacex.com/news/2014/05/30/dragon-v2-spacexs-next...
JshWright 11y ago
These thrusters would be there anyway. The fact that they can be used as the abort mechanism is just a bonus (a well planned and engineered bonus...)
jpk 11y ago
The NASA Commercial Crew program's requirements include a line item for "assured crew return in the event of an emergency."[0] Which means any of the CCDev proposals that use the traditional rocket launch approach for the first stage need an abort mechanism that can carry the crew module away from the rest of the vehicle. So arguably you're right, but they have to develop abort capability per the NASA spec. [0] http://en.wikipedia.org/wiki/Commercial_Crew_Development#Requirements http://en.wikipedia.org/wiki/Commercial_Crew_Development#Req...
mikeash 11y ago
Airliners can't really explode, since they pull in oxidizer from the air rather than storing it on board. Since a fire will spread relatively slowly (relative to a rocket whose oxidizer and fuel decide to make friends all at once), the function of getting the squishy meat payload away from the fire can be accomplished through simpler means, in this case with inflatable slides and the squishy meat payload's own locomotive appendages. That is to say, airliners do have an equivalent system in the form of their evacuation slides, it just looks quite different because airliners operate quite differently.
dwd 11y ago
The history of escape capsules in military aircraft is quite fascinating, but not compatible with an airliner carrying 100s of passengers. http://en.wikipedia.org/wiki/Escape_crew_capsule http://en.wikipedia.org/wiki/Escape_crew_capsule
jccooper 11y ago
Sure, but they're not there yet, and probably won't be for decades and several more generations of designs. And a much higher flight rate: remember, this is an industry where no system has more than 1000 flights, and most don't have 100, and all those are with vehicles that were destroyed in the process. In the meantime, having an abort system is probably a good idea. And besides, it's a customer requirement. And you know how customers are.
simonh 11y ago
I think the key phrase is 'more like' rather than 'the same as'. I don't imagine space travel is ever going to be the same as airline travel, it's always going to involve energies and therefore risks far in excess of commercial airliners. Take engine failure. An airliner with completely failed engines and no motive power at least has a chance of gliding to a landing, without any additional safety or backup system. Rockets, not so much. Jet aircraft can recover safely from a whole range of technical issues, but while rockets have a certain latitude for recovery (SpaceX had a first stage engine failure during launch a while back but the flight continued) their resiliency is much more limited. I don't see that changing, and I doubt SpaceX does either.
ceejayoz 11y ago
> Thus eliminating the need for an abort system? SpaceX's abort system is also its normal landing system. They'll have it available even if they never need it.

by burd691 11y ago

cyrus_ 11y ago

Once they are that reliable, I'm sure SpaceX could consider removing the abort system to save on weight. Though I assume that the SuperDracos are designed to also be used in space / on Mars.

greglindahl 11y ago
And for landing back on Earth, just not initially: http://www.spacex.com/news/2014/05/30/dragon-v2-spacexs-next-generation-manned-spacecraft http://www.spacex.com/news/2014/05/30/dragon-v2-spacexs-next...

JshWright 11y ago

These thrusters would be there anyway. The fact that they can be used as the abort mechanism is just a bonus (a well planned and engineered bonus...)

jpk 11y ago

The NASA Commercial Crew program's requirements include a line item for "assured crew return in the event of an emergency."[0] Which means any of the CCDev proposals that use the traditional rocket launch approach for the first stage need an abort mechanism that can carry the crew module away from the rest of the vehicle. So arguably you're right, but they have to develop abort capability per the NASA spec. [0] http://en.wikipedia.org/wiki/Commercial_Crew_Development#Requirements http://en.wikipedia.org/wiki/Commercial_Crew_Development#Req...

mikeash 11y ago

Airliners can't really explode, since they pull in oxidizer from the air rather than storing it on board. Since a fire will spread relatively slowly (relative to a rocket whose oxidizer and fuel decide to make friends all at once), the function of getting the squishy meat payload away from the fire can be accomplished through simpler means, in this case with inflatable slides and the squishy meat payload's own locomotive appendages. That is to say, airliners do have an equivalent system in the form of their evacuation slides, it just looks quite different because airliners operate quite differently.

dwd 11y ago

The history of escape capsules in military aircraft is quite fascinating, but not compatible with an airliner carrying 100s of passengers. http://en.wikipedia.org/wiki/Escape_crew_capsule http://en.wikipedia.org/wiki/Escape_crew_capsule

jccooper 11y ago

Sure, but they're not there yet, and probably won't be for decades and several more generations of designs. And a much higher flight rate: remember, this is an industry where no system has more than 1000 flights, and most don't have 100, and all those are with vehicles that were destroyed in the process. In the meantime, having an abort system is probably a good idea. And besides, it's a customer requirement. And you know how customers are.

simonh 11y ago

I think the key phrase is 'more like' rather than 'the same as'. I don't imagine space travel is ever going to be the same as airline travel, it's always going to involve energies and therefore risks far in excess of commercial airliners. Take engine failure. An airliner with completely failed engines and no motive power at least has a chance of gliding to a landing, without any additional safety or backup system. Rockets, not so much. Jet aircraft can recover safely from a whole range of technical issues, but while rockets have a certain latitude for recovery (SpaceX had a first stage engine failure during launch a while back but the flight continued) their resiliency is much more limited. I don't see that changing, and I doubt SpaceX does either.

ceejayoz 11y ago

> Thus eliminating the need for an abort system? SpaceX's abort system is also its normal landing system. They'll have it available even if they never need it.