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More on the Orbital Space Plane
AP has a decent piece looking at NASA's orbital space plane program, and describing it as a sedan compared to a tractor-trailer. National polls show that public support for the space program continues to be very strong.
Of course, NASA will select the design with wings, probably the most expensive and error-prone variant, because it will be pushed through by the aerospace industry lobby.
We will observe this agency bypass any principle of common sense and experiences from successful space programs, just to have a new shiny and politically pleasing toy. It's like re-inventing the wheel - this time not a round, but a square shaped one.
What's so bad about winged designs?
- Wings are useless during launch and in space, they just add to weight penalty.
- Winged vehicles are unstable during re-entry and need a complex and error-prone automatic flight control system.
- Wings are less fault tolerant and more vulnerable to damage.
The worst idea is however to put a winged vehicle on top of a rocket! This concept has been repeatedly rejected due to very good reasons, the most important one being the high lateral and bending loads on the rocket!The good old ballistic capsule still holds all safety records in manned spaceflight - there are only very few lethal accidents, related to the large number of successful launches and returns. The Apollo capsule could land in an area of about 2 miles diameter so accuracy is not such a big concern. It could be further improved by using a parawing instead of parachutes.
The only real problem with ballistic capsules is the high re-entry deceleration due to the low drag and therefore the late beginning of aerobraking. However, no astronaut was ever killed due to re-entry or landing impact deceleration and the problem could be dealt with by using additional inflatable structures to increase drag during the early re-entry phases.
The Shuttle, and any next generation craft, is an attempt at creating not just a reusable vehicle, but also one which offers control at landing at a specific place; in this case a runway. Unlike a reentry capsule, which decends to some semi-random location by parachute, the Shuttle can glide toward a specific spot and land. This is a definite step up from previous capsuls in terms of technology and space readiness. And NASA wanted to do even better with their nextgen shuttle, the X-33 design goals were 'single stage to orbit', and would have allowed for a launch and land system without the costly solid fuel rockets. Also a reasonable design goal. Too bad the materials science for the hydrogen tanks isn't quite ready yet, nor are funds available to continue R&D.
NASA is failing because of two primary problems:
a) They lack funding from Congress, and as such are unable to both meet their launch goals and provide the necessary R&D for nextgen launch vehicles.
b) They have foolishly cut safety funding in order to meet those same launch goals, as demanded by Congress. They should have either said straight - we can't meet your goals with the funding alloted, or dumped the Shuttle program and moved to traditional rockets (as you stated in your previous post).
But to say that their R&D toward an orbital space plane was misplaced goes against the very grain of space exploration. At some point we're going to need vehicles that can operate in both space and the atmosphere. NASA obviously committed themselves toward the goal of creating such ships. Space will go nowhere if we only launch rockets into LEO and land in capsules by parachute. You can argue that our materials technology isn't ready yet for the challenges creating real land to space ships, but you can't argue that such a technology is the end goal for any space faring society.
This is JMO, coming from someone who isn't either an aerospace engineer or involved with NASA - and as such has simply a semi-informed opinion to offer.
Best,
Maynard