Space shuttle for space tourism and first stage of a TSTO.

This article describes the plan to sell the orbiters minus engines
for $42 million:

For sale: Used space shuttles. Asking price: $42 million apiece
By John Matson
Dec 18, 2008 04:00 PM in Space
http://www.scientificamerican.com/bl...ing-2008-12-18

It is currently intended only to be sold to educational institutions,
or governmental agencies.
The Air Force is looking for designs for reusable first stage
boosters for two-stage-to-orbit (TSTO) systems. Then it might be able
to be used for this purpose. Most likely you would use kerosene fuel
for this since dense fuels are more suitable for first stages.
The payload bay would be converted to a fuel tank, and the second
stage of the TSTO would be carried on top or below the orbiter. High
performance kerosene engines such as the Russian NK-33, with a near
legendary thrust/weight ratio of 136.66 to 1 at a weight of 1,222 kg,
could be used for propulsion:

NK-33.
http://www.astronautix.com/engines/nk33.htm

The orbiter without the SSME engines masses around 68,600 kg:

Atlantis.
http://www.astronautix.com/craft/atlantis.htm

Its payload bay is around 300 cubic meters that could be used for
propellant. Using the densities of kerosene and lox given he

Lox/Kerosene.
http://www.astronautix.com/props/loxosene.htm

and the oxidizer to fuel ratio of the NK-33 of 2.8 to 1 we can
calculate the propellant load that can be carried as about 300,000 kg.
You would need at least 3 of the NK-33's to lift this fuel load,
orbiter and second stage.
The tank weight of kerosene/lox is typically around 1/100th of the
propellant weight so around, 3,000 kg. Then the empty weight of the
reconfigured orbiter would be 68,600kg + 3*1,222kg + 3,000kg =
75,266kg. And the fully fueled weight of this stage would be
375,266kg.
For this first stage alone without a second stage, this would be a
mass ratio of about 5. Using an average Isp of the NK-33 of 315 you
could get a delta-V of 315*9.8*ln(5) = 4,970 m/s, about Mach 15.
A total delta-V this high raises the possibility it could be used for
suborbital space tourism or point-to-point hypersonic transport, if
sale to commercial organizations were to be allowed.


Bob Clark

Robert Clark writes:

The payload bay would be converted to a fuel tank, and the second
stage of the TSTO would be carried on top or below the orbiter.

With that top or bottom mounted 2nd stage using cryogenic fuels?

Ooops, here we go again....

Unless, double hulled?

Dave

And no SRB's?

BTW, unless Vandenberg can be recomissioned with minimal $$$, how does this
help the Air Force? Seems like a pricey option as far as ground support
goes as opposed to flying ELVs in the orbits most favored.

The cost isn't in the orbiter, it's in the ground support and prep.

As far as a hypersonic transport you'd need 3 orbiters or a crew
compartment capable of flying 7 people, unless they're riding in
a can atop the thing. Not to mention that unless you build duplicated
launch facilities at the destination, you either have to send only the
can and return the orbiter to launch point, *or worse*, fly the thing back on
the back of a 747, thus ticketed passengers are also paying for the
dead head subsonic return flight, unless you're planning on putting
passengers in the transport 747 for the return flight. Plus with all
that extra drag, what it the range of that 747? Refueling stops needed
along the way?

If the can (2nd stage) is resuable it always has to be returned somehow,
even if the flyback 'orbiter' portion does not. How's that done economically?
FexEx? DHL? UPS?

Any handle on the cost to prep the shuttle for flight minus the SSMEs?
I'm skeptical that you could keep the cost low enough to be able to
provide reasonable ticket charges. Not to mention the fact that hardware
upgrades/replacements are out of the question w/o expensive retooling...

Dave

David Spain writes:

As far as a hypersonic transport you'd need 3 orbiters or a crew
compartment capable of flying 7 people, unless they're riding in
a can atop the thing.

Oops, I meant *next to* the thing...

Dave

Pat Flannery writes:

David Spain wrote:
And no SRB's?

BTW, unless Vandenberg can be recomissioned with minimal $$$, how does this
help the Air Force? Seems like a pricey option as far as ground support
goes as opposed to flying ELVs in the orbits most favored.

Maybe it's supposed to fly off of a runway?

Pat

I think we're bordering into this realm...

http://tinyurl.com/ygqzzud

;-)

Dave

David Spain wrote:
Robert Clark writes:

The payload bay would be converted to a fuel tank, and the second
stage of the TSTO would be carried on top or below the orbiter.

With that top or bottom mounted 2nd stage using cryogenic fuels?

Ooops, here we go again....

Unless, double hulled?

I can't for the life of me figure out why Robert Clark is constantly
coming up with ideas for so radically modifying something that already
exists that it effectively becomes a entirely different spacecraft, but
without the advantages that a whole new design would offer.

Pat

David Spain wrote:
And no SRB's?

BTW, unless Vandenberg can be recomissioned with minimal $$$, how does this
help the Air Force? Seems like a pricey option as far as ground support
goes as opposed to flying ELVs in the orbits most favored.

Maybe it's supposed to fly off of a runway?

Pat

David Spain wrote:

As far as a hypersonic transport you'd need 3 orbiters or a crew
compartment capable of flying 7 people, unless they're riding in
a can atop the thing.

Oops, I meant *next to* the thing...

Now picture a SR-71...now picture a SR-71 with a SRB strapped to its
back, a big LOX tank attached under either of its engine nacelles, and a
SSME converted to LOX/JP-7 in its tail...now picture that riding on a
giant take-off trolley, with a trained Chimpanzee in the cockpit...but
not just any Chimpanzee...a Chimpanzee that has been genetically
modified with Bald Eagle DNA to give it an intuitive ability to
understand flight... ;-)

Pat

On Jan 6, 3:02*am, Pat Flannery wrote:
....
I can't for the life of me figure out why Robert Clark is constantly
coming up with ideas for so radically modifying something that already
exists that it effectively becomes a entirely different spacecraft, but
without the advantages that a whole new design would offer.

Pat

The $42 million costs for the basic spacecraft is significantly less
than the $150 million development cost of the Whiteknight2 and
SpaceShipTwo:

Sales are rocketing at Virgin Galactic.
http://www.virgingalactic.org/2008/0...are-rocke.html

and the result would be a vehicle that could do significantly more
than the Virgin Galactic system. It could act as a suborbital space
tourism vehicle, but it also could act as a very high speed point-to-
point transport system. Imagine a cross-Atlantic trip instead of
taking 6 hours only took 1/2 hour. Or a cross country trip instead of
taking 5 hours only took 20 minutes.
Moreover, it could also serve as the reusable first stage of a TSTO.
I'm arguing it could be used to reduce the costs to space if used as a
reusable first stage booster for a TSTO system. The Air Force for
instance believes such a TSTO could cut launch costs by 50%.
The Russian engines that would need to be added would be relatively
low cost. According to this page, in the mid 90's Aerojet purchased 36
of them from the Russians for only $1.1 million each(!):

NK-33.
http://en.wikipedia.org/wiki/NK-33#History

Installation of the lox/kerosene tanks and modifications to
strengthen the body frame to carry the extra loads would also be
relatively low cost.
The 68,600 kg empty weight of the orbiter sans engines could probably
be reduced also. The main system that could probably be removed would
be the Orbital Maneuvering System (OMS). This is used for final
orbital insertion of the shuttle and changes of its orbit. This
wouldn't be needed for a first stage vehicle or a suborbital vehicle.
I don't trust the value given for the OMS weight however on the
Atlantis Astronautix page. It says this:

Main Engine: OME. Main Engine: 14,912 kg (32,875 lb). Main Engine
Thrust: 53.367 kN (11,997 lbf). Main Engine Propellants: N2O4/MMH.
Main Engine Propellants: 12,412 kg (27,363 lb). Main Engine Isp: 316
sec. Spacecraft delta v: 700 m/s (2,290 ft/sec).

The OME refers to the OMS engine. The engine does not weigh 14,912
kg. Perhaps they are referring to the entire OMS system, both pods.
That seems unlikely as well, unless they are including the propellant
weight.
In any case it's this OMS system weight that I'm trying to find out
to subtract off.


Bob Clark

Pat Flannery writes:

take-off trolley, with a trained Chimpanzee in the cockpit...but not just any
Chimpanzee...a Chimpanzee that has been genetically modified with Bald Eagle
DNA to give it an intuitive ability to understand flight... ;-)

Is that Chimpanzee over-caffinated too?

:-)

Dave