Does NASA save money reusing SRB's?

Does NASA really save money by reusing SRB's rather than using
expendables?

This is something a lot of people I know in the industry have wondered.
By the time you recover them, tear them down, ship them to Utah, clean
them out, and inspect them, does it really cost less than it would to
just build new hardware at higher production rates? I know solids
engineers who think NASA can't possibly save money on them.

The other red flag is that solid strap-ons have been used for decades by
many other countries (particularly Ariane) and other domestic expendable
launch systems, yet nobody else reuses their solids. I can understand
why other launch organizations wouldn't have use for other aspects of the
reusable Shuttle because their missions are different (commercial
launches only, no manned or down-payload needs), but it seems to me that
solid strap-ons are solid strap-ons... they all do pretty much the same
thing regardless of mission or what vehicle they're attached to. Being
solids they have robust empty strength and they have relatively short
burn times and stage at relatively low altitudes so they are well suited
for recovery compared to any other type of stage.

Either you save money by recovering/reusing solid strap-ons or you don't,
and the fact nobody else flies reusable solids suggests that nobody else
thinks it's a money saver, or at the very least the recurring savings
aren't enough to justify the up-front investment required. Long after
Shuttle SRB's were flying, Ariane V and Atlas V in particular chose to
invest in clean-sheet large expendable solid strap-ons. The only things
I can think of in Shuttle's defense are that the SRB's are extremely
large (perhaps this changes the economics) and they're also more
sophisticated than other solid strap-ons, so the hardware cost may be a
bigger percentage of the stage cost than most solids, so there's more to
be saved by reuse.

Assuming NASA doesn't actually save money by reusing SRB's, do you think
it is due to:

1) The early Shuttle paper studies suggested they would save money and
it just didn't ultimately pan out, and they either can't or don't want to
change now.

2) NASA wanted to sell the Shuttle as reusable and dictated the SRB's
be reusable for political/marketing reasons, and they either can't or
don't want to change now.

3) NASA's accounting is so screwed up that they have don't have usable
data to accurately calculate the cost difference between reusable and
expendable SRB's, so they have no idea if they should change.

4) NASA's management has no incentive to expend the effort required to
find out if reuse actually saves money because discovering expendables
are cheaper only makes them look bad, so even if the data is out there
managment wouldn't want to gather and analyze it.

The Apprentice wrote:

Does NASA really save money by reusing SRB's rather than using
expendables?


It's apparently something of a wash, but the numbers I've seen indicate
a slight edge for reusability.

Both expendable and reusable RSRMs would get substantially cheaper at
substantially higher flight rates


The other red flag is that solid strap-ons have been used for decades by
many other countries (particularly Ariane) and other domestic expendable
launch systems, yet nobody else reuses their solids.


Soyuz has launched over 6000 of their strap on liquid boosters, and
haven't recovered a one. Would they be cheaper recoverable? Dunno. At
thier flight rate... probably.

I can understand
why other launch organizations wouldn't have use for other aspects of the
reusable Shuttle because their missions are different (commercial
launches only, no manned or down-payload needs), but it seems to me that
solid strap-ons are solid strap-ons... they all do pretty much the same
thing regardless of mission or what vehicle they're attached to. Being
solids they have robust empty strength and they have relatively short
burn times and stage at relatively low altitudes so they are well suited
for recovery compared to any other type of stage.


Titan III solids were seriously examined for reusability. Being steel
cases, that made sense. However, a lot of modern solids are smaller and
made from composites, like the GEM motors, of which somethign like 800+
have flown; the GEMs static test fired on the pad have shown that they
are *not* refurbishable.


Either you save money by recovering/reusing solid strap-ons or you don't,


Same goes with liquid.

Assuming NASA doesn't actually save money by reusing SRB's, do you think
it is due to:

1) The early Shuttle paper studies suggested they would save money and
it just didn't ultimately pan out, and they either can't or don't want to
change now.



One issue would be cranking up the productionr ate of the case segments.
This is non-trivial. I gather the lead time for a new segemnt is on the
order of *years*.



--
"The only thing that galls me about someone burning the American flag is how unoriginal it is. I mean if you're going to pull the Freedom-of-speech card, don't be a hack, come up with something interesting. Fashion Old Glory into a wisecracking puppet and blister the system with a scathing ventriloquism act, or better yet, drape the flag over your head and desecrate it with a large caliber bullet hole." Dennis Miller

Scott Lowther wrote in
:

The other red flag is that solid strap-ons have been used for decades
by many other countries (particularly Ariane) and other domestic
expendable launch systems, yet nobody else reuses their solids.

Soyuz has launched over 6000 of their strap on liquid boosters, and
haven't recovered a one. Would they be cheaper recoverable? Dunno. At
thier flight rate... probably.

If anything your point about Soyuz raises the question whether reuse of
strap-ons *in general* saves money. If it did wouldn't *somebody* in
the world (besides NASA) have at least tried it, after concluding it had
potential during their paper studies? The Soviets spent a staggering
amount of money developing the Energia/Buran system from scratch -- why
didn't they spend a tiny fraction of that at some point to make Soyuz
strap-ons reusable -- amoritized over the *thousands* of Soyuz stage-
flights?

If nobody has done something (reusing stages), it's wrong to say we know
it's a good idea. This is one thing I've grown tired of hearing from
people in the industry as if it's a proven fact (somehow apparently known
by everyone except those who choose never to build them). We have two
data points on reusable space vehicles that have been built and flown:
Shuttle and Buran. While it's true that Buran was cancelled for
cost/benefit reasons, since it was such a blatant copy of the Shuttle I
think we can say it isn't a second independent data point. So that
leaves us with only one data point -- the Shuttle, and we know it was a
failure on cost/benefit. All the other talk of reusable systems are
simply speculation or at best paper studies. For all we know there are
problems common to any reusable system that we haven't identified yet
because we haven't built more than one system to see the pattern.

The fact nobody besides NASA has tried to do it suggests others don't
believe it's a good idea. That's not to say they can't all be wrong
(since nobody tried it), but the fact that many minds from many cultures
have looked at the same issue and come to the same decision is something
we shouldn't ignore.

Personally I think there's more potential for reusing strap-ons than any
other stage, and I hope that somebody actually builds one to get us more
data on their advantages/disadvantages. Odds are it will take several
iterations before we get to something that doesn't have unexpected
problems and comes out ahead on cost, or it may simply prove that
expendables are always cheaper. I hear the Air Force wants to do a
demo, though I doubt they'll have the money as long as we're in Iraq.


Titan III solids were seriously examined for reusability. Being steel
cases, that made sense. However, a lot of modern solids are smaller
and made from composites, like the GEM motors, of which somethign like
800+ have flown; the GEMs static test fired on the pad have shown that
they are *not* refurbishable.

Yes, I figured small solids would be less suitable than large ones for
reuse. That's why I cited Atlas-V and Ariane-V as examples, because
they have large solids. As you point out Titan is also something to
look at, though I chose to use examples of recent designs that are
currently in production.


Either you save money by recovering/reusing solid strap-ons or you
don't,

Same goes with liquid.

Yes, but with liquids there tend to be a lot more differences in terms of
engine design & cost, stage size, burn time, etc that make blanket
statements about them less appropriate. Strap-on solids have a lot more
in common with each other than their liquid counterparts have with each
other, so we can draw conclusions about solid strap-ons as a group with
greater confidence than we can with their liquid counterparts.

Soyuz, if memory serves, uses peroxide powered turbines to pump storable
propellants in a strap-on application. Titan used storables to power
their turbines and they were 1st stage engines rather than strap-ons.
SSME is a closed-cycle high pressure LOX/LH2 main engine located apart
from its tanks. And so on. My point is that there tends to be a lot
of factors with liquids that complicate apples-to-apples comparisons and
the ability to assess their potential for reusability.


One issue would be cranking up the productionr ate of the case
segments. This is non-trivial. I gather the lead time for a new
segemnt is on the order of *years*.

Yes, I wasn't trying to suggest that it would be trivial for NASA to
switch. "NASA can't change" = might have cost less if chosen from the
start, but future recurring saving don't justify the cost of changing
now, or it is a political impossibility. "NASA won't change" = would
still save money going forward but are too stupid or conservative to make
the right decision.

On Sat, 27 Aug 2005 12:56:20 -0500, in a place far, far away, The
Apprentice made the phosphor on my
monitor glow in such a way as to indicate that:

Scott Lowther wrote in
:

The other red flag is that solid strap-ons have been used for decades
by many other countries (particularly Ariane) and other domestic
expendable launch systems, yet nobody else reuses their solids.

Soyuz has launched over 6000 of their strap on liquid boosters, and
haven't recovered a one. Would they be cheaper recoverable? Dunno. At
thier flight rate... probably.

If anything your point about Soyuz raises the question whether reuse of
strap-ons *in general* saves money.

There is no simple answer to that question. It depends largely on the
flight rate. Few if any existing launch systems currently have a high
enough flight rate to justify reusability.

"Rand Simberg" wrote in message
...
On Sat, 27 Aug 2005 12:56:20 -0500, in a place far, far away, The
Apprentice made the phosphor on my
monitor glow in such a way as to indicate that:

Scott Lowther wrote in
:

The other red flag is that solid strap-ons have been used for decades
by many other countries (particularly Ariane) and other domestic
expendable launch systems, yet nobody else reuses their solids.

Soyuz has launched over 6000 of their strap on liquid boosters, and
haven't recovered a one. Would they be cheaper recoverable? Dunno. At
thier flight rate... probably.

If anything your point about Soyuz raises the question whether reuse of
strap-ons *in general* saves money.

There is no simple answer to that question. It depends largely on the
flight rate. Few if any existing launch systems currently have a high
enough flight rate to justify reusability.

One reason I have heard for reusing (or at least recovering) Shuttle SSBs is
the opportunity for the engineers to see the condition of the boosters after
their use and how well, or not, their design has performed.

On Sat, 27 Aug 2005 19:35:19 +0000 (UTC), in a place far, far away,
"John Burch" made the phosphor on my monitor
glow in such a way as to indicate that:

If anything your point about Soyuz raises the question whether reuse of
strap-ons *in general* saves money.

There is no simple answer to that question. It depends largely on the
flight rate. Few if any existing launch systems currently have a high
enough flight rate to justify reusability.

One reason I have heard for reusing (or at least recovering) Shuttle SSBs is
the opportunity for the engineers to see the condition of the boosters after
their use and how well, or not, their design has performed.

If so, that's a new one, post-Challenger. The original idea was to
save money through reuse.

"John Burch" wrote in
:

One reason I have heard for reusing (or at least recovering) Shuttle
SSBs is the opportunity for the engineers to see the condition of the
boosters after their use and how well, or not, their design has
performed.

I doubt that could possibly have been a real consideration when the Shuttle
was being defined. After all, expendable solids are recovered and
evaluated. Solid cases regardless of reusability tend to survive intact
because of the pressure loads they're designed for.

I'm curious how much they recovered Saturn-V 1st stages and inspected them.

John Burch wrote:


One reason I have heard for reusing (or at least recovering) Shuttle SSBs is
the opportunity for the engineers to see the condition of the boosters after
their use and how well, or not, their design has performed.





There is considerable truth in that. And the sorta-converse is also
true: one (minor) reason why GEMs aren't recovered, and no effort made
to even try to fish one out, is because they *don't* want to see just
how ratty the things look. As with the ET foam thing, the less you know,
the less you have to explain.

--
"The only thing that galls me about someone burning the American flag is how unoriginal it is. I mean if you're going to pull the Freedom-of-speech card, don't be a hack, come up with something interesting. Fashion Old Glory into a wisecracking puppet and blister the system with a scathing ventriloquism act, or better yet, drape the flag over your head and desecrate it with a large caliber bullet hole." Dennis Miller

Rand Simberg wrote:
There is no simple answer to that question. It depends largely on the
flight rate. Few if any existing launch systems currently have a high
enough flight rate to justify reusability.

You seem to be implying that high flight rate favors reuse of strap-on
solid boosters; I'm curious as to your reason for this? Usually the main
reason for economy of scale comes from the fact that you can use more
automation and still cover your fixed costs; and I would have thought
the activity of rolling new boosters off a production line, was a lot
more amenable to automation than the activity of fishing used boosters
out of the sea, shipping them back to the factory, disassembling,
cleaning and inspecting etc?

--
"Always look on the bright side of life."
To reply by email, replace no.spam with my last name.

On Tue, 30 Aug 2005 19:02:14 +0100, in a place far, far away, Russell
Wallace made the phosphor on my monitor
glow in such a way as to indicate that:

Rand Simberg wrote:
There is no simple answer to that question. It depends largely on the
flight rate. Few if any existing launch systems currently have a high
enough flight rate to justify reusability.

You seem to be implying that high flight rate favors reuse of strap-on
solid boosters; I'm curious as to your reason for this?

Because there are high fixed costs that have to be amortized over the
number of flights.

Usually the main
reason for economy of scale comes from the fact that you can use more
automation and still cover your fixed costs; and I would have thought
the activity of rolling new boosters off a production line, was a lot
more amenable to automation than the activity of fishing used boosters
out of the sea, shipping them back to the factory, disassembling,
cleaning and inspecting etc?

Whether or not it's automated or not is a separate issue. Either way,
small levels of activity don't justify reusable systems, large ones
do.