[QUOTE=Waverly]
Rocket science is not so very difficult. The core of rocket science is propulsion technology, and this really hasn’t changed appreciably since the 1960’s. NASA and the US military use the same materials in the engine systems, the same fuels, and the same basic approach that they did then. Ditto on heat shields. There have been some minor changes in the fuselage, specifically lighter weight composites – but this isn’t exactly rocket science. The only radical changes would be to the avionics and computer systems.
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And these changes are radical indeed. It’s not quite right to say that they use the same engine systems and materials, but it’s unfortunately too close to the truth, with new large liquid engine develepment pretty much stalled in early-to-mid 'Seventies and using the de Laval nozzle used in Goddard’s time. Solid boosters (for ICBMs/SLBMs) have seen some developments in nozzle design (expanding nozzles), propellants (high energy low sensitivity casts), and flight control, but these developments are more evolutionary and revolutionary. There has been development and testing of aerospike and single expansion ramp nozzles, but nothing that has come to a production application. The liquid engine being used on the Ares I booster for the Orion spacecraft is the J-2X, a development of the J-2 from the Saturn family of rockets, and the liquids from the first stage of the Ares V is the RS-68 (also used in various configurations of the Delta IV Heavy) which–along with the cancelled RS-83–are the first large liquid engines developed in the US in the last 25 years. The RD-180 engine used in the competing Lockheed Martin Atlas V EELV is derived from a Russian design used on their N-1 rocket. (These were ordered destroyed when the Soviet Moon shot program was cancelled but were mothballed by a far-sighted bureaucrat and revealed to shocked Western engineers after the fall of the Soviet Union.)
On smaller engines and station-keeping thrusters work with ion and electric motors continues apace, which application on many commerical satellites and use on interplanetary craft like Deep Space 1 and Hayabusa. Larger plasma-based propulsion is also an active area of research, but is slow going due to the complexities of magnetoplasmadynamis. Research into nuclear thermal rockets (or electric/plasma engines with a nuclear fission power source) has stalled due to political factors and technological hurdles, and of course the nuclear pulse propulsion ORION-type rocket is completely politically unviable.
That being said, rocket science and engineering is far from “not so very difficult”. Even using 40 year old technology rockets still push the edge of material capabilities, and the complexity of the systems is such that elaborate, labor-consuming efforts in quality assurance and risk abatement are required to obtain confidence in a successful launch, and even then a 95% launch success rate for a booster design is considered acceptible. (If commercial aircraft crashed in 1 out of 20 flights, there would be no air travel.) In liquid fuels we’re still using primarily kerosene, LOX, hydrogen, and occasionally storable hypergolics like hydrazine not because we haven’t come up with anything better but because there doesn’t appear to be anything more chemically energetic for mass or volume (depending on what you are trying to minimize) in nature. Getting more performance out of liquid rockets means making the engine more efficient, not finding higher energy fuel, and that becomes an exercise in incremental improvement, inching toward maximum ideal performance of the fuel itself.
Personally, I think “brain surgery” (neurosurgery, neurology, neurophysiology, and neuropsychiatry) are more complex than rocket propulsion insofar as we have only a very limited understanding how the equiment even works on a fundamental level, and the complexity of the brain is certainly many orders of magnitude more sophisticated than anything manmade. When we have a seemingly intractible problem at work, our comment is usually “Well, it’s not brain surgery.”
Stranger
