The X-33 is not cancelled in 2001.

What if the X-33 technology had succeeded and what would be its impact on the Space Shuttle's replacement?

http://en.wikipedia.org/wiki/Lockheed_Martin_X-33http://www.wikipedia.org

2 possible solutions: aluminum instead of composites, or a better quality control, so that the problems with composites are targeted earlier.

Outcome: A space shuttle which is only slightly less expensive than the old one (let's forget the official numbers - the space shuttle was supposed to cost half as much as rockets but ended up costing far more than conventional technology), only slightly more reliable (after the first few flights), only slightly more capable, but much better in looks.

There would be many more flights with the new shuttle, until it has it's first fatal accident - then up to 2 years no flights.

Btw., it seems the shuttle is actually in production again - though not in the public space...
 
What if the X-33 technology had succeeded and what would be its impact on the Space Shuttle's replacement?

http://en.wikipedia.org/wiki/Lockheed_Martin_X-33
the biggest problem is that they bit off more than they could chew. NASA has a mandate to advance technology and to improve access to space. Basically every time they try to do the latter, they end up getting bogged down with the former.

Doing an SSTO means EVERYTHING has to work right. a 1% weight increase can make the whole project infeasible. That's why they had to use the carbon-fiber tanks - because nothing else was light enough and strong enough.

What they probably should have done was a TSTO with an X-33 type vehicle as the upper stage. But, no, that wasn't fancy enough, and so they bet the whole farm on a very risky project that failed.
 
One other possibility. The McDonnell-Douglas DC-X derived vehicle gets choosen instead. It had a much better chance of actually flying.
 
Not one, but TWO fantasies

There were TWO fantasies at work in the X-33, so it really had no chance. There was Pournelle's society's holy grail status for SSTO. There was NASA's fantasy of spaceplanes being progress

NASA's performance shows a long history of fantasy about spaceplanes being progress. There were hopes until recently that a spaceplane could cheapen travel by compressing oxygen on the way up, a ramjet. What they should've done after Apollo, of course, was built another rocket for big lifting jobs, and build spaceplane X- vehicles until they had found out how expensive they to build and especially maintain (turnaround maintenance is $B/shuttle mission), and canned it. In fact, in reality, we've found can't build a useful ramjet, because it gets too hot and at current tech we can't fix that or live with it.

SSTO DOES have some promise - but it's strictly limited. Pournelle believed any kind of SSTO would be alot simpler and cheaper to build, but X-33's spaceplane complexity is a pretty powerful counterexample. Really, all you can hope for is an incremental lowering of prices for low-end boosters. In the end, Pournelle proved to be just another of the politicians without engineering experience he often accused of betrayal of the future. His first job after serving in Korea was, in fact, politics, hmmm.....
 

burmafrd

Banned
IF we were to start from scratch right now and design and build a new shuttle it would probably be what we originaly thought we were getting back in the late seventies. Technology has advanced to a point where it probably would work right. The problem was that the shuttle never realy had a chance to fulfill the totally unreasonable expectations that it was sold on.

A space plane is a great concept and would work just like a transport plane does today. The real problem is that engine technology has not really advanced much in the area we need it to: ramjet or something like it. THAT is what is needed= the solid fuel boosters and huge fuel tank pretty much damned the shuttle to never really being what it needed to be.
 
There are mentionings of a X-something (i think) being slowly developed by someone (USAF, DARPA?) to give US military independent and rapid space access. I think the numbers are x-37, and/or x-41. Since its perfectly reasonable to have NASA develope Ares launch vehicles, DOD suporting Atlas and Delta, and developing a new purely millitary shuttle. Whats that about some deficit? :p
 
new scramjet under test

\The problem with the ramjet isn't the engines, but rather heat shielding that can deal with that kind of speed in the air. I haven't heard of any better solution to the $Bs-postflighting heat shield problem, either. At least NASA has finally understood those problems and is moving to a cheaper heavy-lift rocket system. The X-41 is a test platform for a possible suborbital strike system.

OTOH, this thread has inspired me to do my periodic check of GlobalSecurity's X-* page. A new X-51 scramjet test vehicle is scheduled for testing any day now. It has a specially shaped hull that they hope will produce a so-called WaveRider effect that'd let it slice through oncoming waves and encourage air pressure waves to build up around the X-51 instead of breaking on it.

The X-51 is still untested and missile-sized, so don't expect people or big things to go scramjet soon. But, just having a working scramjet that doesn't burn up will be quite the accomplishment if it works.
 

Archibald

Banned
SSTO can't work with current technology.

More exactly, reusable SSTO.

As bizarre as its sounds, Saturn stages, taken separately, could have been SSTO.
I mean, takes a S-IVB, put in on the pad, light the J-2. The things will go to orbit; it is light enough, and as enough fuel.

Problem n°1 : you won't recover it. It has no heatshield nor landing system. If you add them, the S-IVB become too heavy, and can't go to orbit.

Problem N°2 = Payload is very weak: nearly all the stage is fuel (92%).

the SSTO problem is as simple as that.


What works (as of today) is TSTO, two stage to orbit. That give you something reusable.
Until the 90's the stages had to be winged to be recoverable (a bit like the shuttle).

Then come the Kistler K-1 team, with a genial idea : land the stages using parachutes and airbags.

That's much lighter than wings, undercarriage, cockpit, tail...

The Kistler K-1 is much less glamourous than a spaceplane, but would probably works better.

Add a reusable Apollo capsule on top, and there you are, a fully reusable manned spacecraft.
 
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