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From this article, I gather that ULA is trying to build reusability into their next generation of launch vehicles. Their plan is summed up nicely in the picture:

ULA Reusability

In the article, they seem to do some really weird math:

“This will take up to 90 percent of the propulsion cost out of the booster. And this is just the beginning.”

The engines represent a quarter of the first stage’s overall weight and 65 percent of the booster cost, according to ULA.

If the engines only represent 65 percent of the cost, how can they possibly save 90 percent of the cost when they only recover that part? Some other issues I have in this statement:

  • What about the cost of the recovery, such as the helicopter, boat, logistics personnel etc. ?
  • What about the additional weight added to the system for the heat-shield, parachute, coupling between Engine and ATS etc. ?
  • How many times can an engine be reused? If it can only be reused 10 times, the cost of the engines is divided by 10, not reduced to zero.
  • How much would it cost to refurbish? Considering that the recovery system (Heat-shield and parachutes) would also need refurbishment
  • There is also a very real risk of failure to recover based on this system which don't seem to be taken into consideration.

My question is: What would a realistic estimate be of the cost savings involved?

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I might give some answer to your five bullet points, although I don't have a number for the estimate cost (I doubt anyone has):

1) Cost of recovery: It should if anything be lower by capturing the engines in midair than having to soft land them on their own. Replacing the autonomous landing system and its fuel of the F9R with an ordinary helicopter sounds potentially very economical! (65% and 90% must be a misunderstanding somewhere).

2) Additional weight: It might turn out that SPX too will have to reuse only the engines of the F9R, but going through alot more trouble to do so than the new ULA idea, we'll see. The chopper is supposed to replace alot of the complexity and mass of the SPX concept for F9R and Dragon 2.

3) Reusability frequency: Soon no one will want to launch the same gadget more than 10 times because the vehicle will be ancient by then. And anyway 1 reuse gives 50% maximum potential production cost reduction (+50%!), 2 reuses gives 66% (max pot) cost reduction (+16%), 3 reuses gives 75% reduction (+9%), 4 reuses gives 80% reduction (+5%) and then no one cares anymore, almost all potential has already been won anyway. Going from a ninth to a tenth reuse only lowers costs per launch by 1%. Not counting refurbishment costs which likely increase by every reuse per rocket.

4) Refurbishment costs: Less than for anyone else, thanks to the unpowered descent and soft parachute midair capture. ULA Vulcan engines will be as good as any used rocket engine could be. Heat shields are not needed when reusing the first stage.

5) "Failure"? No, that is not an option anymore! Computer power, sensors, costs, materials, mass, batteries, ease of use and more have already gotten to where some PhD students prove that total precision air capture is trivial today.

The ULA is today not in the position where they could hope to confront SPX frontally by trying to copy their concept. But by diversifying into some other mode of reusability, they might succeed if the concept of SPX fails. You might have heard of "asymmetric strategy".

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    $\begingroup$ Related: space.stackexchange.com/questions/3456/… $\endgroup$ – Deer Hunter May 18 '15 at 20:36
  • $\begingroup$ Thanks for this. I find the last paragraph on asymmetric strategy very insightful. Would still like to see costs, but this may be a good direction for ULA. Hope it finds its way off the drawing board and into real life $\endgroup$ – neelsg May 20 '15 at 12:17
  • $\begingroup$ @neelsg Costs? How much have you got? This could cost somewhere between anything and everything. They wouldn't get started if they were sure. You might find some drawing board calculations, but everyone know that it is just a training exercise for new recruits. The ULA certainly has the ability to transform concepts to real rockets. No doubt about that, they have proven it. It is only about their incentives. How their abilities could be put to good use. I'm sure they have libraries with good ideas, they just pick out one which fits what they are paid to do. $\endgroup$ – LocalFluff May 20 '15 at 12:57
  • $\begingroup$ "Soon no one will want to launch the same gadget more than 10 times because the vehicle will be ancient by then" -- how so? Spacex's reusability work aside, rockets haven't changed much in decades. $\endgroup$ – radex Dec 28 '15 at 7:55

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