Space shuttle for space tourism and first stage of a TSTO.
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From: Robert Clark on 5 Jan 2010 10:26 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/blog/post.cfm?id=for-sale-used-space-shuttles-asking-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 here: 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
From: David Spain on 6 Jan 2010 00:44 Robert Clark <rgregoryclark(a)yahoo.com> 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
From: Pat Flannery on 6 Jan 2010 03:02 David Spain wrote: > Robert Clark <rgregoryclark(a)yahoo.com> 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
From: David Spain on 6 Jan 2010 01:05 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
From: David Spain on 6 Jan 2010 01:11
David Spain <nospam(a)127.0.0.1> 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 |