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Orbital Space Plane Problems
FTL writes "NASA's next big step in space (after getting the remaining Shuttles flying again) is the construction of the Orbital Space Plane. It is a small vehicle designed to transport people to and from ISS. Jeffrey Bell takes a close look at OSP in this article and comes to the conclusion that it will result in yet another crippled vehicle. Sounds like what people were saying about the Shuttle's problems back when it was being designed."
The X-prize is suborbital. Still, supporting a similar orbital prize may very well be a good idea.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"Orbital Space Plane @ orbital.com
Orbital Space Plane @ globalsecurity.org
Actually, during the late 1980's there were some serious studies of building a small spaceplane that could be launched from the top of a modified 747-200.
Essentially, the 747-200 would be fitted with a de-rated version of the Space Shuttle main engine, which will allow the 747 with the spaceplane on top to do a steep 35 degree climb to around 50,000 feet. The spaceplane, which has a small external fuel tank attached, would then launch at that altitude and fire its engines (essentially 3-4 RL-10's used by the Centaur upper stage) for a 7 minute flight to orbit. Because the launch happens at 50,000 feet, there is no need for the spaceplane to lug along a big load of propellant fuel, and that means it could carry a load as large as seven crew members or its equivalent weight in cargo to the International Space Station. I can envision by 2014 crews will visit the ISS either by using this new spaceplane or much-updated versions of the Soyuz spacecraft; ISS consumables and future extensions to the space station will be brought up by lifting them to orbit on uprated versions of the Atlas V and Delta IV Heavy rockets plus updated versions of the Russian Proton rocket.
Indeed, the guy who wrote it did sound like a smart ass.
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The United States has come to the point of a reusable space-plane a number of times and at the last minute gives it up.
Like the X-15. It flew, it worked, the engine worked, 1 man to almost space, it could have gone to space and back but the budget was cut.
http://www.hq.nasa.gov/office/pao/History/x15/c
Dyna-Soar
ttp://www.aerospaceguide.net/dynasoa
http://www.astronautix.com/craft/dynasoar.
X-24
http://www.astronautix.com/craft/x24a.htm
What he says about "advanced technology" is pretty much spot on.
When you look at our "advanced boosters" - in a basic sense, all they are is old early cold-war-era ICBMs, retrofitted with Solid Rocket Boosters. Atlas, Delta, and Titan. The last REAL innovation in US booster technology was Saturn V.
I agree with several points he made - about how VTOHL is kind of retarded. Launching big heavy wings vertically, so the craft can land horizontally is ridiculous. But he overlooks some of the alternatives.
Lifting Bodies - X-33 was a spectacular failure - only because when confronted with adversity, WE GAVE UP. Part of that was the failure of the guys who set the budget unrealistically low in the first place, and let it overrun past the point of credibility. But if you want weight-savings in not sending wings up vertically, that's the way to do it. There's one real technicall challenge - an oddly-shaped fuel tank able to repeatedly deal with the pressurization cycle. And we just rolled over and quit when the first few attempts failed. I think that's sad.
Horizontal Take-off - Pegasus has been a spectacular success. If you're going to put wings on your craft, you may as well Horizontal Take-Off. Most of the launch fuel of getting a vehicle into space is used up in the first 5 miles. I don't know if there's a good way to fix this problem cheaply - we already "blew our wad" so-to-speak, but here's what we can do maybe in 10 years:
Justify the development of a new, VERY large multi-purpose transport aircraft - like the Galaxy C-5, only, in order to take advantage of economy of scale, use the same principle used in the JSF program. One plane that fulls multiple roles. Here are the roles:
Heavy Bomber (to replace the B-52).
Cargo Transport (to support loads the C-5 cannot handle)
Commercial Passenger plane (I know, we can't justify the Boeing double-decker, but at one point, it was at least worth thinking about).
Launch Vehicle Deployment.
Currently, the Pegasus can loft a tiny 1000lb payload into orbit. It's taken up to 40,000 ft by an L-1011, which is a pretty large plane. A plane on the scale of what I'm talking about could horizontally loft a next-generation spaceplane up to 40,000 ft, separate, and return to the ground, for mere peanuts compared to what it costs to prep your typical Atlas/Titan/Delta/Arianne. From 40,000 ft, scramjets can get this plane to 80,000 ft and Mach 8-12. (another technology we would need to develop, but it will save the weight of carrying oxidizer). Booster rockets can get it to Orbit. (either a SRB strap-ons, or perhaps the scramjets can be fed oxidizer).
Admittedly VERY complicated technology, but this is the evolution we were looking at 15 years ago with VentureStar, and other variants. And they were abandoned, due to lack of vision at the federal level. This lack of vision stems from a lack of a pissing-contest with the Russians, like we had when we were going to the moon.
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
Your entire comment makes the rather broad assumption that air density is the same at sea level, 10km and 150km. I'm kind of thinking it drops pretty quickly.
.000460, air density at sea level is .002377, so air density at 45,000 feet is about 1/5 that of sea level (google rocks, chart 1).
It saves quite a bit of fuel because there is significantly less drag at 10km than there is at sea level. 10km would be, what, pretty much 35 thousand feet, but the service ceiling of an unmodified 747 is 45,000 feet (google owns you).
Air density at 45,000 feet is
So, if the 747 dropped the payload at 45,000 feet, and the payload gained altitude at a good rate, it would require significantly less rocket fuel than taking off from the ground. In addition, the payload could have smaller fuel tanks, which means smaller pipes, less structure and less insulation to fall off and ding a wing.