Re: Griffin Wants Inline SDLV and 5 Segment SRB/CEV


"Rand Simberg" <simberg.interglobal@xxxxxxxxx> wrote in message
news:42e8f943.172050325@xxxxxxxxxxxxxxxxxxxxxxxxxxx
> On Sun, 10 Jul 2005 21:39:58 -0400, in a place far, far away, "Murray
> Anderson" <murraya@xxxxxxxxxxxx> made the phosphor on my monitor glow
> in such a way as to indicate that:
>
> >
> >"Rand Simberg" <simberg.interglobal@xxxxxxxxx> wrote in message
> >news:42e7eedd.169387997@xxxxxxxxxxxxxxxxxxxxxxxxxxx
> >> On Sun, 10 Jul 2005 19:07:35 -0400, in a place far, far away, "Murray
> >> Anderson" <murraya@xxxxxxxxxxxx> made the phosphor on my monitor glow
> >> in such a way as to indicate that:
> >>
> >> >> >It wasn't necessary to have a fly-back booster - just recover the
> >liquid
> >> >> >boosters the way the SRB's are recovered.
> >> >>
> >> >> That would still have cost more than they had budget for (solids are
> >> >> cheaper to develop than liquids, honest), and it's not at all clear
> >> >> how refurbishable a liquid in that class would be after being
dropped
> >> >> in the ocean, Truax's limited experiments aside.
> >> >
> >> >They didn't know how refurbishable the solid would be either.
> >>
> >> They did, since they don't refurbish it--they rebuild it from the
> >> recovered segments, with new grain.
> >>
> >It's the same with a liquid booster, except for the engine assembly - you
> >just refill the tanks.
>
> No, it's not that simple. The solids consist of segments, which can
> be broken down and rebuilt. A liquid would have huge tanks that would
> have to be inspected.
>

That doesn't establish an advantage for the solids. You could just as well
say the liquids have tanks that only have to be inspected whereas the solids
have to be rebuilt.

> >The engine nozzle and gimballing system of the solid are supposedly
> >recovered and reused, which would be like the engine assembly on the
> >liquid - except for the turbopump system.
> >There would be a difference if the turbopump system were harder to
protect
> >from seawater than the gimballing system on the solid.
>
> As indeed it would.

You have a source for this?

>
> >> >> Delta IV heavy doesn't have the payload they want, and getting it
> >> >> (with man rating) probably will cost more than the development of
the
> >> >> Satay.
> >> >>
> >> >
> >> >The payload was supposed to be 25 tons
> >>
> >> Emphasis on "was."
> >>
> >
> >And the advantage of the stick is what? It doesn't exist so it can't be
> >demonstrated not to meet the spec until it flies?
>
> Again, go argue with them. I'm not defending the Satay.
>
> >> >I
> >> >> >accept that they can't do any better but don't quite see the
> >connection
> >> >> >between original design decisions and the flight rate. I'm not
talking
> >> >about
> >> >> >the fantasies of 50 flights a year, but 10-12 a year would have
been
> >very
> >> >> >helpful after the space station was started.
> >> >>
> >> >> Because they didn't design it for rapid turnaround, again due to
> >> >> limited development budgets.
> >> >
> >> >That's a restatement of the problem in other words, together with a
> >> >rationalization. What was it they wanted to do and didn't have the
money
> >> >for? A better thermal protection system would help, but that wasn't on
> >> >offer, was it?
> >>
> >> With more money, yes. They could have, for example, used a titanium
> >> structure underneath, instead of aluminum.
> >>
> >But the problem is the susceptibility to debris damage, not the
insulating
> >qualities of the tiles.
>
> That's only part of the problem.
>

And what is the other part of the problem?

> >Unless the tiles were all replaced by thermal
> >blanket and it was less susceptible to damage. Anyway, was that the
reason
> >for using aluminum? I thought it was a combination of manufacturability,
> >which is more schedule-related, and concern about interference with
military
> >programs.
>
> It was for manufacturability, but that relates back, ultimately, to
> cost.
>
> >The leading edges would would still require carbon composite, but that
> >susceptibility is more safety-related than maintenance related, so
wouldn't
> >impact schedule.
>
> I've no idea what this means.
>

I didn't think they did enough work on the carbon composite between flights
to interfere with the schedule.

> >> >Similarly, the external tank shouldn't shed foam to damage
> >> >the tiles, but what tank design was turned down because it cost too
much?
> >>
> >> The one that was incorporated into the Orbiter.
> >
> >That would imply a totally different design, possibly with dense
> >propellant - and you may well be right about the cost here.
>
> Yes. The point is that we had a very expensive "Shuttle"
> operationally because we were unwilling to spend the money up front to
> make it otherwise.

Murray Anderson


.

Relevant Pages

  • Re: Griffin Wants Inline SDLV and 5 Segment SRB/CEV
    ... >>> That would still have cost more than they had budget for (solids are ... >>> how refurbishable a liquid in that class would be after being dropped ... >>> probably will cost more than the development of the ... >>The record is good for solids, and is consistent with the view reported ...
    (sci.space.policy)
  • Re: A very basic question...
    ... A lot of chemistry necessary for life requires liquid solvents. ... Lots of different scientists from lots of different countries stand behind the same claim. ... Most solids are denser than their liquid phase, sink to the bottom and stay there allowing the entire bulk the solidify. ...
    (uk.sci.astronomy)
  • Re: Does NASA save money reusing SRBs?
    ... yet nobody else reuses their solids. ... If nobody has done something, it's wrong to say we know ... Personally I think there's more potential for reusing strap-ons than any ... > Same goes with liquid. ...
    (sci.space.policy)
  • Re: Griffin Wants Inline SDLV and 5 Segment SRB/CEV
    ... The solids consist of segments, ... A liquid would have huge tanks that would ... >>That doesn't establish an advantage for the solids. ... the liquid tanks could be made somewhat heavier if necessary. ...
    (sci.space.policy)