Shuttle Derived Launchers - Safe, Simple, Soon

"Jeff Findley" wrote:


"Derek Lyons" wrote in message
...
(Henry Spencer) wrote:

In article iAIve.89500$yV4.76348@okepread03,
wrote:
We might be able to get SSME cost down, once they don't have to be
built for 20 flights each.

Henry, I believe you have the relevant exact quote needed here...
I think it was one of the original liquid rocket engine developers
who said he didn't know *how* to build a one-time-use rocket engine.

Del Tischler, NASA's first propulsion man -- he wrote the specs for the
F-1, among other things -- gave a talk at Space Access 94, titled "The
Myth Of The Short-Duration Engine". One of his first comments was "I
don't know how to build a non-reusable liquid-rocket engine."

I'd wager he doesn't know how to build an actually re-useable one
either.

And how do you arrive at that assertion?

Because he'd never built one.

But it does make a very nice sound bite - of which you've
become all too fond of Henry.

I agree that it is typical of Henry to refer to an actual talk by an expert
in the field.

An actual soundbite by an expert in the field. We all know what
soundbites are worth however.

I take it you attended the same conference? You also know
that Del Tischler oversaw the development of more than just the F-1, right?
I believe he also oversaw the development of the RL-10, which was
successfully used as a "reusable engine" on the DC-X program, despite its
previous uses were all "expendable".

I notice the quotes around "reusable engine". It emphasizes the very
point I am making - an engine that gets a dozen flights worth of run
time isn't reuseable by any rational standard - except for the space
industry, which also accepts 98% as a reasonable safety margin.

The F-1 was meant for a single flight with a burn time of about 150s, but
its spec nevertheless called for 20 starts and 2250s total burn time,
because of practical necessities like testing and calibration. Six
life-test engines ran over 5000s each.

The key question is how much (if any) maintenance those engines
recieved/required. Did they spend their lifetime being coddled, or
were they (mostly) subject to service conditions? (I say mostly
because they decidely didn't endure the thermal, atmospheric, or
vibration regimes that an in-service engine would.)

When one looks at regeneratively cooled rocket engines, there isn't
typically much wear and tear in them.

If one doesn't count all the moveable parts, seals, etc... No, there
isn't much wear and tear in them. But if you set those parts aside,
you haven't much of a useful engine do you?

Also, as Henry said, you want to be able to test fire them, and you want
to have quite a bit of safety margin built in as well. This led to the
"disposable" F-1 specs looking suspiciously like a "reusable" engine, even
though its use on the Saturn V was "disposable".

It didn't look anything like a reuseable engine - to those able to
look honestly and openly.

Certainly the devil is always in the details, but with regeneratively cooled
engines, a sane engineer isn't likely to put in components known to be one
shot, at least not without making them easier to replace after a test
firing. Ignoring all else, it makes the test program go much easier than if
you have to keep tearing down your test engine after every firing.

The opposite of one-shot isn't long life.

This is in stark contrast to liquid fueled engines that have ablatively
cooled throats and/or nozzles. That design has a definite finite life to
them before you have to tear them down and replace all of the ablatively
cooled parts.

Once again I try to shine light - but you prefer the warm comfortable
darkness of dogma.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

On Tue, 28 Jun 2005 03:09:25 GMT, (Derek Lyons)
wrote:

I'd wager he doesn't know how to build an actually re-useable one
either.

And how do you arrive at that assertion?

Because he'd never built one.

....Not having built one doesn't mean that they don't know how. I know
how to build a house, having studied the required techniques. However,
lacking the funds, I have *not*. Ditto for a reusable - no hyphen,
kids - engine. It's quite probable that he knows *how*, just not how
to do it -cheap-.

OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr

In sci.space.policy Brian Thorn wrote:
On Mon, 27 Jun 2005 20:53:21 +0300 (EEST), meiza
wrote:

Brian Thorn wrote:

The Atlas 5 Super
Heavy seems to require new tooling for a wider core stage and a new
pad to launch it from.

Interesting..
What is the first stage diameter and configuration of the Atlas 5
Super Heavy in the Aviation Week article? What engines?

5.4 meters, same engines but two of them instead of one.

Strange, they didn't go for Delta IV diameter (5.1 meters). I guess
that's not a big enough increase from the current 3.8 meters.
I wonder if they can adapt some of the tooling though, it's not
such a big increase, now that the construction of both launchers is
consolidated.
Also, they use two rd-180's and not a single rd-171 (would have 70%
common parts). Maybe there was too much hassle dealing with the
Russians.

If they put more of these first stages in parallel for a big
Saturn V-class launcher, the dual engines can have a reliability
advantage (can the stack take an engine-out?). Single-stick they're
just a liability.

--
-meiza

In sci.space.shuttle Ed Kyle wrote:
wrote:
Here's a hint: a new VAB for a properly designed heavy lifter wouldn't
*need* to be as big as the current one.

It could be horizontal instead of vertical.

A shuttle-derived vehicle can't be assembled
horizontally due to the 590 tonne mass of each
SRB. By comparison, the entire Energia/Buran
stack only weighed about 300 tonnes empty.

Isn't can't a bit strong?
1500 tons is admittedly 5 times 300 tons, but building a crane/...
to do the job does not seem an enormous task.

Ian Stirling wrote in
:

In sci.space.shuttle Ed Kyle wrote:
wrote:
Here's a hint: a new VAB for a properly designed heavy
lifter wouldn't *need* to be as big as the current one.

It could be horizontal instead of vertical.

A shuttle-derived vehicle can't be assembled
horizontally due to the 590 tonne mass of each
SRB. By comparison, the entire Energia/Buran
stack only weighed about 300 tonnes empty.

Isn't can't a bit strong?
1500 tons is admittedly 5 times 300 tons, but building a
crane/... to do the job does not seem an enormous task.


Hoisting an assembled SRB to vertical by picking it up from
one end is probably a very bad idea. It'll bend, distorting
the propellant grain. That can lead to a Very Bad Day when
it's ignited. There's more than one reason those things are
built and stacked in sections.

--Damon

Ian Stirling wrote:

A shuttle-derived vehicle can't be assembled
horizontally due to the 590 tonne mass of each
SRB. By comparison, the entire Energia/Buran
stack only weighed about 300 tonnes empty.



Isn't can't a bit strong?
1500 tons is admittedly 5 times 300 tons, but building a crane/...
to do the job does not seem an enormous task.


It would be quite something to see- even the Buran/Energia transporter
looked like something "Wings Over The World" would have in "Things To
Come": http://electronicintellect.net/Baikonur/crawler/6.jpg
http://electronicintellect.net/Baikonur/crawler/4.jpg
One of the big problems would be how to move it around on the soft soil
of the Kennedy Space Center which is only a bit above sea level.
Putting the erector crane on the pad itself would simplify things some,
but given the high cost of developing this new way of doing things it's
virtually a sure bet that the stick gets assembled vertically in the VAB
and taken to the pad by the crawler transporter- despite the cost of
doing it this way. The whole concept here is to use off-the-shelf
components for the sake of simplicity and getting things operational
ASAP, and using the VAB and CT is right in line with that concept.

Pat

On Wed, 29 Jun 2005 22:50:06 -0500, Pat Flannery
wrote:

One of the big problems would be how to move it around on the soft soil
of the Kennedy Space Center which is only a bit above sea level.
Putting the erector crane on the pad itself would simplify things some,
but given the high cost of developing this new way of doing things it's
virtually a sure bet that the stick gets assembled vertically in the VAB
and taken to the pad by the crawler transporter- despite the cost of
doing it this way.

I really don't see how it makes a big cost difference whether you
stack on the launch pad or in the VAB. Stacking is still going to take
time and manpower. Better to do it in the much more benign
environmental and worker safety conditions of the VAB than at the
seaside pad. Rollout itself only costs you one day. There's no
fundamental reason that the SRB, Stage II, and an Apollo-like CEV
should need to spend a month on the pad before launch. Get everything
you can finished in the VAB. Roll it out, fuel it (no hideously toxic
propellants this time, please), and launch.

Brian

Damon Hill wrote:

Hoisting an assembled SRB to vertical by picking it up from
one end is probably a very bad idea. It'll bend, distorting
the propellant grain. That can lead to a Very Bad Day when
it's ignited. There's more than one reason those things are
built and stacked in sections.



You'd have to use a support cradle like on the N-1 transporter:
http://www.nasm.si.edu/exhibitions/g.../381L1bP1b.JPG

Pat

--Damon

Brian Thorn wrote:

I really don't see how it makes a big cost difference whether you
stack on the launch pad or in the VAB. Stacking is still going to take
time and manpower. Better to do it in the much more benign
environmental and worker safety conditions of the VAB than at the
seaside pad. Rollout itself only costs you one day. There's no
fundamental reason that the SRB, Stage II, and an Apollo-like CEV
should need to spend a month on the pad before launch. Get everything
you can finished in the VAB. Roll it out, fuel it (no hideously toxic
propellants this time, please), and launch.



That's pretty much what the Russians do with Soyuz- it only heads to the
pad shortly before launch:
http://www.interspacenews.com/sections/feature%20stories/russia's%20soyuz%20booster.htm
has the launch timeline, and some nice shots of the vehicle I hadn't
seen before.

Pat

Ian Stirling wrote:
In sci.space.shuttle Ed Kyle wrote:
wrote:
Here's a hint: a new VAB for a properly designed heavy lifter wouldn't
*need* to be as big as the current one.

It could be horizontal instead of vertical.

A shuttle-derived vehicle can't be assembled
horizontally due to the 590 tonne mass of each
SRB. By comparison, the entire Energia/Buran
stack only weighed about 300 tonnes empty.

Isn't can't a bit strong?
1500 tons is admittedly 5 times 300 tons, but building a crane/...
to do the job does not seem an enormous task.

The resulting crane would have to be one of the
strongest land cranes. Maybe something like the
LTL-2600 found at "http://www.lampsoncrane.com/".
The rocket would have to be firmly supported within
a massive rigid cradle, which would add hundreds
more tonnes mass for the tilt/lift operation to deal
with.

The operation would probably take a couple of days,
which would be one day more than a standard vertical
roll-out (Boeing needed two days for its much
smaller horizontally-integrated Delta IV Heavy - one
to roll out and one to erect). The lift would be
wind-limited, and hazardous, etc. So the expense
of the crane and cradle wouldn't buy any schedule time.

So yes, "can't" was the wrong word. "Shouldn't"
would have been a better word.

- Ed Kyle