What do you think of the SLS?

[Spica]

The bigger the fuel tank, the bigger the LES. This danger is trivial.

-Duxwing

Well, bigger LES means more fuel needed to lift LES, which means yet a larger LES, which means more fuel needed to lift THAT, larger LES.

And so the vicious cycle continues...

[Dodgey]

That this is a valid concern:

Well then I respectfully disagree. There is no evidence that I am aware of that would suggest reused rockets are significantly less reliable than those which are not reused.

[Dodgey]

Well, bigger LES means more fuel needed to lift LES, which means yet a larger LES, which means more fuel needed to lift THAT, larger LES.

And so the vicious cycle continues...

I'm sorry what? There is a maximum lift rating on any rocket and the payload which includes the LES is always within that lift limit. By that logic no rocket will ever fly because to launch a payload you need fuel, and to launch that fuel you need more fuel, to launch that more fuel ect ect.

[Jouni]

Well then I respectfully disagree. There is no evidence that I am aware of that would suggest reused rockets are significantly less reliable than those which are not reused.

People generally assume that a rocket is unreliable, until there is enough evidence to the contrary. Especially if their money is at stake.

[maccollo]

Well, bigger LES means more fuel needed to lift LES, which means yet a larger LES, which means more fuel needed to lift THAT, larger LES.

And so the vicious cycle continues...

And a person can never catch a tortoise.

[Skyrunner27]

Yes, a PAD abort test. It is more probable that tons of debris will go flying towards the capsule faster than the capsule can accelerate away.

The shuttle had two total launch failures.

How is it going to be the safest? That's completely ridiculous. A HUGE explosion, as big if not bigger than a tactical nuclear warhead, is somehow safe?

Yeah, PERFECTLY LOGICAL.

The Orion abort system will work similar to this. The flight you are actually watching had an unplanned abort even though it was a test for abort. The reason the shuttle had fatalities was that if the orbiter lost its wings it would not be able to land safety. Challenger had the crew cabin survive for most of the fall with several crew members being unconscious. Here you have parachutes. Remember it is not the fall that kills you it is the sudden stop at the end.

- - - Updated - - -

[KASASpace]

Would you please elaborate? The inflatables are for space travel.

It sounded as if you were talking about using them on the surface of Mars.

Corporations can arbitrarily raise prices only in a monopoly; whereas in such competitive markets as NASA launch vehicles, only the cheapest satisfactory seller gets any money and all sellers therefore seek to lower their prices just enough to win. In case you were wondering, the same principle applies elsewhere; e.g.,

No, they will raise the prices a substantial amount, and then the next competitor lowers theirs after raising it, but only to just beat the previous. You're right, but that's AFTER They already increased their prices.

[KASASpace]

The Orion abort system will work similar to this. The flight you are actually watching had an unplanned abort even though it was a test for abort. The reason the shuttle had fatalities was that if the orbiter lost its wings it would not be able to land safety. Challenger had the crew cabin survive for most of the fall with several crew members being unconscious. Here you have parachutes. Remember it is not the fall that kills you it is the sudden stop at the end.

I understand how the abort system will work, I just don't believe that what they say holds true. It being able to pull a, what is it? Ah, yes. 8913 kg mass all the way OUT of a giant cloud of flame and debris quick enough.

At 18 gees, that would be 176.4 m/s^2, correct? So, basically, more Gees than Mercury flights. In fact, that's barely survivable. Plus, you would need 87347.4 kilogram-force. Or, basically, 856004.52 Newtons of force. That's a lot of thrust. And you would need more than that for the entire LES being pulled as well.

Okay, so, 176.4 m/s^2 over 10 milliseconds? No where near the speed needed.

[maccollo]

Okay, so, 176.4 m/s^2 over 10 milliseconds? No where near the speed needed.

How do you know that?

[KASASpace]

How do you know that?

1 millisecond = 0.001 seconds.

10 milliseconds = 0.010 seconds.

Now, accelerating 176.4 m/s^2 means that after every second, we gain 176.4 m/s in velocity.

Over 0.01 seconds we are going 1.764 m/s. That sounds nowhere near enough to get away from an exploding rocket.

[maccollo]

Over 0.01 seconds we are going 1.764 m/s. That sounds nowhere near enough to get away from an exploding rocket.

How do you know that? What is your source?

[Duxwing]

It sounded as if you were talking about using them on the surface of Mars.

Oh.

No, they will raise the prices a substantial amount, and then the next competitor lowers theirs after raising it, but only to just beat the previous. You're right, but that's AFTER They already increased their prices.

Play your mental model for more turns and you'll see I'm right. If Company A makes an SLS for $1 million and offers it for $4 million, and if Company B therefore makes an SLS for $1 million and offers it for $3 million, then Company A can make $1 million by offering its SLS for $2 million. The market will reach equilibrium with space parts just like it does for apples.

-Duxwing

[Jouni]

We have a real-life example of a launch escape system pulling Soyuz orbital module and descent module succesfully from a burning rocket, even though it took 20 seconds to activate the system. The rocket exploded two seconds later. The crew survived with minor injuries.

[Duxwing]

We have a real-life example of a launch escape system pulling Soyuz orbital module and descent module succesfully from a burning rocket, even though it took 20 seconds to activate the system. The rocket exploded two seconds later. The crew survived with minor injuries.

A forced example of Cool Guys (and Girls) Don't Look At Explosions.

-Duxwing

[Dodgey]

People generally assume that a rocket is unreliable, until there is enough evidence to the contrary. Especially if their money is at stake.

It isn't a question of the total reliability of the rocket, but a comparison of the reliability of a new rocket compared to the reliability of a refurbished one.

[KASASpace]

Play your mental model for more turns and you'll see I'm right. If Company A makes an SLS for $1 million and offers it for $4 million, and if Company B therefore makes an SLS for $1 million and offers it for $3 million, then Company A can make $1 million by offering its SLS for $2 million. The market will reach equilibrium with space parts just like it does for apples.

That 2 million is still more than the 1 million it actually cost Company A

[KASASpace]

How do you know that? What is your source?

There is an equation, and a rather simple one at that.

speed = acceleration * time

So, over 0.01 seconds, you get only 1% of your acceleration.

[RocketPilot573]

I like the Falcon Heavy better. If SpaceX can really make it reusable then, it might actually get somewhere.

[maccollo]

There is an equation, and a rather simple one at that.

That sounds nowhere near enough to get away from an exploding rocket.

How do you know THAT?

[R0cketC0der]

1 millisecond = 0.001 seconds.

10 milliseconds = 0.010 seconds.

Now, accelerating 176.4 m/s^2 means that after every second, we gain 176.4 m/s in velocity.

Over 0.01 seconds we are going 1.764 m/s. That sounds nowhere near enough to get away from an exploding rocket.

I don't think 10 milliseconds is the time the escape tower fires, it's the time it need to react to an emergency.

[Jouni]

It isn't a question of the total reliability of the rocket, but a comparison of the reliability of a new rocket compared to the reliability of a refurbished one.

Still, the same principle applies. There is considerable evidence that new kinds of rockets often fail catastrophically. As long as there is no significant evidence on the reliability of refurbished rockets, it's best to assume that they are less reliable than new rockets of the same kind.

[KASASpace]

How do you know THAT?

Because, debris is flying at faster velocities with even more force in almost all directions.

- - - Updated - - -

I don't think 10 milliseconds is the time the escape tower fires, it's the time it need to react to an emergency.

And if that emergency happens before it reacts? It's quick, I'll give it that, but 10 milliseconds isn't that great.

[maccollo]

Because, debris is flying at faster velocities with even more force in almost all directions..

How fast does the debris accelerate and what velocity does it reach in the different directions? What is your source for this claim/how did you calculate it?

[Dodgey]

And if that emergency happens before it reacts? It's quick, I'll give it that, but 10 milliseconds isn't that great.

It reacts at the first sign of trouble. That question is akin to asking what happens if it doesn't fire. It's a worst case scenario which we hope will never happen.

[Red Fang]

Most rocket explosions do not propagate the same way that those of explosives do. They are slower and less powerful when not induced by a RSO. If a consequence of break up of the rocket, it takes seconds to ignite all the fuel in the tanks. Most debris follows a narrow cone along the speed vector of the rocket. So LAS has to get the pod away and to the side from the rocket. There is always going to be a chance that the a stray fragment or a SRB out of control will hit the pod, but based on the descriptions and videos of Orion LES, I'd say it raises the chances of crew survival, in the event of a launch failure significantly.

Also, debris that hit the crew pod, have to damage it as well, and red hot aluminium is not well known for its armor piercing properties and damage potential.