[AR] reuse (was Re: SpaceX F9 Launch/Update -- Live Link)
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Thu, 24 Dec 2015 18:44:59 -0500 (EST)
On Thu, 24 Dec 2015, Henry Vanderbilt wrote:
All due respect, but SRB's are simply not a useful reuse economics model
for soft-landing recovered liquid booster stages. As I recall, between
the effects of double-digit-G's water impact and salt immersion, the
only part of the SRB's NASA was actually willing to reuse were the
stripped steel casings, after they were scoured out then checked for
cracks.
My understanding was that the lesser subassemblies like the chutes, the
APUs, the electronics packages, etc. did get a certain amount of reuse...
after dismantling, cleaning, inspection, reassembly, re-testing, etc.
But I have no direct positive confirmation of that.
Even granting that, I think it's misleading to apply the word "reuse" to
the SRBs at all. As complete rocket stages, they weren't really reused in
any meaningful sense. The whole process was really much closer to
SpaceX's original "reuse" concept, in which the first stage was going to
splash down and get fished out, and then selected parts would be salvaged
from it for use in building another one. SpaceX never made this work, and
eventually gave up on it; the politics of reusability made NASA persist
(aided by the greater durability of solid stages) until it was at least
superficially working. But it remained more a matter of component salvage
than of true stage reuse.
It remains to be seen what level of teardown and refurb Blue's and
SpaceX's boosters will require, but the equivalent of an SRB "refurb" is
way over at the far end of the range of probabilities.
Concur. Just getting the thing down intact and *dry* should make a huge
difference. The first few naturally are going to be gone over with a
fine-tooth comb, looking for any hint of future trouble, so it'll take
some time to see what the numbers are like for operational reuse. I'd say
that much will depend on how much attention reuse got during development
of things like the structures. (As HV noted, it's reasonable to assume
some design adjustments based on early reuse experience. But serious
structural redesign would be costly.)
Henry
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