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

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

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

On Jan 6, 8:56*am, Robert Clark wrote:
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:


*Installation of the lox/kerosene tanks and modifications to
strengthen the body frame to carry the extra loads would also be
relatively low cost.

This is just more BS from Clark. When his non viable ideas are nixed
on one forum, he goes and posts the same crap on another forum.

The 42 million costs for the basic spacecraft is a drop in the bucket
compared to the costs of all the mods. Also you don't even consider
the mods for ground operations. The orbiter has no structural
interface with the launch pad, it just hangs on the ET, so how do you
propose to sit the orbiter on its tail

The mods to carry the propellant tanks would not be "low cost", it
would require an extensive mod to the vehicle, which would be
basically a rebuild.

Clark, face it, you don't know what you are talking about and your
ideas are not workable.

Me wrote:
Clark, face it, you don't know what you are talking about and your
ideas are not workable.

You know, it would be possible to convert a 747 into a earth-boring
machine at fairly low cost also.
All we have to do is make the wings jettisonable...add a LOX-kerosene
rocket engine to its tail...

Pat

On Jan 6, 11:12*am, Me wrote:
...
This is just more BS from Clark. *When his non viable ideas are nixed
on one forum, he goes and posts the same crap on another forum.
..

Actually I post them all at the same time. ;-)

Bob Clark

On Jan 6, 8:56*am, Robert Clark wrote:
...
*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.


Used alone without a second stage it could achieve high hypersonic
speeds. The hypersonic, subsonic, and reentry characteristics of the
orbiter are well understood. Once used as a first stage, it might lead
trade studies to be done to see if a vehicle of similar dimensions but
made of all composite construction could have a significantly better
mass ratio. Could it even reach orbit?
I would like to see a breakdown of the orbiter subsystem weights to
see which ones could be removed for this application, and which ones
such as the frame and body panels could be replaced with lightweight
composites, if anyone knows a reliable source for this. The
Astronautix page on the Atlantis gives some subsystem weights
including the airframe structural weight but their numbers can be
unreliable.
As a first guess, I'm thinking that going to an all-composite version
of the shuttle with propellant tanks in the payload bay would not
allow this reconfigured shuttle to reach orbit. However, there is a
significant amount volume in the wings, at about a 250 square meter
wing area and maximum wing thickness of 1.5 meters. This could amount
to a propellant tank volume near that of the payload bay. Note that
for aircraft it is common to hold the fuel in the wings.
The shuttle wings would need significant strengthening to hold this
higher weight however. This would add on to the dry weight. However,
again as a first guess, use of this wing volume on an all-composite
version would give you a vehicle that could reach orbit. Then you
would have a fully reusable SSTO.



Bob Clark

On another forum someone reminded me, you could just use wet wings as
the propellant tanks. As a preliminary estimate, the wing volume may
be close to that of the payload bay based on a wing area of 250 square
meters and a maximum wing thickness of 1.5 meters. Then you could keep
the large shuttle payload bay to carry payloads while having close to
the same propellant load. You would need some strengthening of the
wings though, which would increase the dry weight.


Bob Clark

"Pat Flannery" wrote in message
dakotatelephone...
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.

I don't know, but I solved the problem long ago by putting him in my
killfile.

Jeff
--
"Take heart amid the deepening gloom
that your dog is finally getting enough cheese" - Deteriorata - National
Lampoon