Moon and Mars expeditions vs. RLV development

"Ool" writes:

Yeah. To bad the *military* has no use for a rocket that can touch
down again in one piece...

You're joking right? Who do you think funded the original development
of the DC-X, the only reusable "rocket" that has proven through flight
testing that VTVL landing of "rockets" is feasible?

Jeff
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"Paul F. Dietz" wrote:

Dick Morris wrote:

The Shuttle is not an RLV, so it's hard to see how it could. Throwing
away a $60 million External Tank on every flight is not how to build an
RLV, and it certainly cannot lead to low costs, so the Shuttle proves
nothing.

Even if the ETs were free, the shuttle launches would not be significantly
cheaper. The cost is from the standing army of workers and low flight rate,
which ultimately comes back to complexity and tight engineering margins.

But ET's are NOT free, and that $60 million cost by itself is enough to
put the Shuttle into the ELV price range. That effectively precludes
developing significantly larger markets, which guarantees that the
Shuttle will always have a substantial fixed-cost contribution to the
total cost-per-flight. (Foam flaking off of the ET also greatly
increases the cost of maintaining the Orbiter's TPS.)

The Shuttle's low margins (and lack of redundancy) are the result of
NASA pushing the Shuttle design to the limit in order to maximize the
payload mass-fraction. Absolute maximum performance is the ELV
paradigm: It costs so much to launch a payload with expendable vehicles
that there is an overwhelming incentive to maximize the amount of
payload that each vehicle can carry in order to reduce the cost per
pound of payload. Complexity drives the amount of effort required to
check out a vehicle, but it is the very low reliability due to mass
minimization which makes it necessary to do all that before every flight
in the first place. (The new ET and associated interfaces also MUST be
checked out before every flight.)

Throwing away all, or major portions, of a vehicle drives the recurring
cost through the roof, which drives the market way down, which further
increases the total cost-per-flight, which further depresses the
market. Etc. Going to a partly expendable design put us on the wrong
road, which led to all the other problems that afflict the Shuttle
program. It is a classic vicious cycle, and the only way to break it is
to go to a fully-reusable design.


Paul

Jon Berndt wrote:

"Dick Morris" wrote in message

The Shuttle failed to become a low cost RLV because it was turned into a
Partly Expendable LV.

Well, the ET really is a small price to pay in the whole scheme of things.
The shuttle failed to become a low cost RLV largely because of the support
costs and the inability to be turned around quickly.

The Shuttle system is capable of much faster turnarounds than we have
seen in recent years. Lack of any significant markets became the
primary determinant of the interval between Shuttle flights.

Support costs dominate the cost of a Shuttle launch because the flight
rate is low. The flight rate is low because recurring costs are high.
Getting recurring costs down is the key to resolving the problem, and
ALL causes of high recurring costs must be addressed, simultaneously.

Ool wrote:

"Rand Simberg" wrote in message ...
On Thu, 22 Jan 2004 19:16:51 +0100, in a place far, far away, "Ool"
made the phosphor on my monitor glow
in such a way as to indicate that:
"Greg D. Moore (Strider)" wrote in message ...
"Ool" wrote in message
...
"Greg D. Moore (Strider)" wrote in message
...
"Ool" wrote in message
...

That launcher cost MORE than the shuttle.

How so, with all that dead weight you have to lift along with it in
the form of the Shuttle? What was it that made the Shuttle cheaper?

Bureaucracy. You're focusing on the wrong metrics. Dead weight to orbit
ultimately isn't a great metric.

It is if fuel is expensive.

It's not.

Hydrogen/oxygen/aluminum/polyurethane...? Maybe it isn't.

So what does make the rocket so expensive? The hulls, which burn up
in the atmosphere or get bent out of shape crashing into the sea? The
complexity? The manhours needed? The risk of disaster?

Expending all or major portions of the vehicle drives recurring costs
through the roof, which drives the market down the tube, which increases
the fixed-cost contribution to the total cost-per-flight, which further
reduces the market, etc. The end result is a very low flight rate with
fixed costs dominating the cost of a launch.

Complexity, by itself, is not a major cost driver. It is the need to
test all that complex hardware before every flight which drives up
costs. If the hardware is reusable, reliable, and is designed so that
the vehicle can survive any failure, with continuous abort modes
throughout the flight, there is no need to do all that testing. We can
adopt the philosophy used by the airlines: The best test was the last
flight.

Are there any comprehensible cost estimates listing just what makes
the Shuttle and expendable rockets most expensive?

--
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"jeff findley" wrote in message ...
"Ool" writes:

Yeah. To bad the *military* has no use for a rocket that can touch
down again in one piece...

You're joking right? Who do you think funded the original development
of the DC-X, the only reusable "rocket" that has proven through flight
testing that VTVL landing of "rockets" is feasible?


From the way you're formulating the question I'd hazard that the an-
swer is: The military.

So what use do they have for a rocket that can land softly, ass down?



--
__ “A good leader knows when it’s best to ignore the __
('__` screams for help and focus on the bigger picture.� '__`)
//6(6; ©OOL mmiv :^)^\\
`\_-/ http://home.t-online.de/home/ulrich....lmann/redbaron \-_/'

"Ool" writes:

So what use do they have for a rocket that can land softly, ass down?

How about a reusable VTVL SSTO that would reduce launch costs by an
order of magnitude or more? ;-)

Seriously, back when this was funded, DOD had plans which included
putting lots of mass into orbit. Because existing launch vehicles
were far too expensive, money was spent looking into various ways to
lower this cost. The DC-X program was one of the projects they funded
for this very reason.

Jeff
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"Rand Simberg" wrote in message
...
On Fri, 23 Jan 2004 08:03:16 -0500, in a place far, far away, Kelly
McDonald made the phosphor on my
monitor glow in such a way as to indicate that:


The only way to significantly reduce the cost of launch is to
dramatically reduce the number of people involved.

Or dramatically increase the number of launches. There are more
people involved in air transport than space transportation, but air
transport is affordable.

Careful Rand. You have to get the ratio of people down. Not the absolute
number.

"Ool" wrote in message
...
"Rand Simberg" wrote in message
...
On Fri, 23 Jan 2004 08:03:16 -0500, in a place far, far away, Kelly
McDonald made the phosphor on my
monitor glow in such a way as to indicate that:

The only way to significantly reduce the cost of launch is to
dramatically reduce the number of people involved.

Or dramatically increase the number of launches. There are more
people involved in air transport than space transportation, but air
transport is affordable.


Begging the question, *could* the Shuttle have launched a hundred
times a year if the demand and hence the money had existed? Fifty?
Twenty?


Depends.

As built... no.

Average time between flights for a shuttle is about 3 months. Given work,
you MIGHT get that to 2 months.

But let's assume 3 months.

A given shuttle then can fly 4 times a year.

Four shuttles gives you 16 flights a year.

So, to get say 48 flights a year, you'd need 3 times as many shuttles, or 12
of them.

Ok, next problem.... launch pads.

You've got two. So you have to get 24 flights out of them each. Or two a
month. Which means roll-out to launch has to be 2 weeks or less.

Now, you've got three MLPs. That gives you 16 flights each. Which means
you need to stack the shuttle and SRBs and roll them out in 3 weeks (and
that includes the 2 week window above).

Now, you've really only got 2 bays setup for stacking. Though with enough
money you could outfit one more. So, similar limitation.

Oh, and did I mention you only have 3 OPFs?

So, you've got one orbiter in orbit, one on each MLP, and one in each OPF.
That's 7. Where do you keep the other 5?

So, no, not very possible.

Things that might have been possible:

Decrease turn-around time from landing to launch. This means keeping the
OPF stays SHORT. Like a week. This means making things easier to
check-out, repair, replace. Which drives up mass (and size to an extent).
But since we were going for payload uber alles, we for went that.

Also, go with LFBs early on. Simply stack and fuel at the bad. Less safety
precautions required, etc.

Basically, the current system was just a result of too many compromises.



--
__ "A good leader knows when it's best to ignore the __
('__` screams for help and focus on the bigger picture." '__`)
//6(6; ©OOL mmiv :^)^\\
`\_-/ http://home.t-online.de/home/ulrich....lmann/redbaron \-_/'

On Fri, 23 Jan 2004 15:58:58 +0100, in a place far, far away, "Ool"
made the phosphor on my monitor glow
in such a way as to indicate that:

Begging the question, *could* the Shuttle have launched a hundred
times a year if the demand and hence the money had existed? Fifty?
Twenty?

In theory, but it would have required a lot of additional facilities.
It wouldn't have been the way to go.

On Fri, 23 Jan 2004 23:18:53 GMT, in a place far, far away, "Greg D.
Moore \(Strider\)" made the phosphor on my
monitor glow in such a way as to indicate that:

The only way to significantly reduce the cost of launch is to
dramatically reduce the number of people involved.

Or dramatically increase the number of launches. There are more
people involved in air transport than space transportation, but air
transport is affordable.

Careful Rand. You have to get the ratio of people down. Not the absolute
number.

Isn't that what I said?