Shuttle Evolution Improvements suggested to the shuttle derived from the design as flown. Credit - © Mark Wade

NASA also had ambitious plans - for large space stations, lunar bases, nuclear interplanetary rocket stages, and manned Mars expeditions. NASA went through a long iterative process in designing and selecting the space shuttle, leading ultimately to the same conclusion as the Air Force. Initial Phase A concepts were for two stages, both either winged or lifting bodies, both recovered at the launch site for reuse. NASA explored some alternative concepts, including Lockheed's LS200 single orbiter with drop tank, and Chrysler's SERV ballistic single stage to orbit vehicle, before proceeding to Phase B. The Phase B designs were more refined but still used the same two-stage approach. At this point the controversy were over large cross-range winged designs, medium cross-range lifting body designs, and minimal cross-range stub-wing designs. NASA's Faget strongly pushed for the stub-wing design.

Eventually the Nixon administration advised NASA that not only were there to be no flights to Mars, no nuclear interplanetary stages, no space station, no more Saturn V's, no orbital transfer vehicle - but there wouldn't be a space shuttle either if NASA couldn't get the development cost down and get the USAF to participate. A USAF requirement was a large cross-range to allow recovery of the orbiter at Vandenberg AFB from polar orbits in the case of abort-once-around scenarios. This, together with wind tunnel studies indicating that Faget’s straight wing was unstable at re-entry speeds, drove NASA to the delta wing. The reduction in development cost led NASA to throw away the concept of reusing anything but the engines and guidance systems. Instead the shuttle would be boosted by cheap solid fuel boosters and, taking a concept from the Air Force, the propellants would be put in a big expendable drop tank.

Following the usual charade of competitive bidding, NASA picked the same contractors as for X-15 and Apollo, who would build precisely the vehicle it had in mind. North American Rockwell was selected to build the orbiter, with its Rocketdyne Division making the main engines, Thiokol for the solid rocket boosters, and Martin Marietta for the External Tank, to be built at the government Saturn IC factory at Michoud.

To finance the Shuttle in the austere 1970’s, already-built Apollo hardware that would have supported a second Skylab mission was sent to museums and American manned space flight went into a long hiatus. Budget cuts and overruns reduced the number of shuttles built from five to four and delayed the first flight from 1978 to 1981 (thereby ruining the plan to save Skylab on an early shuttle mission). Although several elements were cancelled (a space tug), the project did not much overrun its original cost (development ended up costing $ 6.744 billion in 1971 dollars, versus $ 5.15 billion estimated - less than a quarter of the Apollo program cost).

The pretext for the shuttle was that it would be much cheaper than expendable launch vehicles and would replace them all. Production was accordingly terminated by the US government of Delta, Atlas, and Titan vehicles. NASA staff and contractors were under incredible pressure to justify this decision by increasing the shuttle launch rate, lowering the turn-around time, and thereby reducing the cost per launch. When the shuttle Challenger exploded and the entire US space lift program was shut down for almost a year, the fallacy of this situation was exposed. The US Air Force and commercial users returned to use of expendable launch vehicles. When the shuttle began flying again, it was only for NASA programs.

In the final analysis the shuttle came up short in two areas. First, the shuttle orbiter ended up almost 20% over its specified weight - resulting in it being unable to boost the US Air Force’s payloads into polar orbits from Vandenberg. Lighter filament-would casing Solid Rocket Boosters were being developed for use in flights from Vandenberg, but even this did not seem enough. After the Challenger explosion the USAF was able to extricate itself from the Shuttle program. The Vandenberg launch complex, built at the cost of billions, was mothballed. The Air Force started a new costly development program to design the Titan 4 expendable rocket for its large military payloads.

The second was that it failed, by most definitions, to reduce the cost of putting payloads into orbit. The shuttle program inherited from Apollo huge fixed costs - the Manned Spaceflight Center in Houston, the cadres of government and contractor workers at the Kennedy Space Center, and so on. The result was that there is a fixed base cost of around $ 2.8 billion per year, just to keep all those people and facilities in place, even if you don’t conduct any flights at all (as occurred after the shuttle disaster). The marginal cost of each flight added to this base is under $ 100 million per year. Seen this way the shuttle is almost competitive expendable boosters - but doesn’t come anywhere near the reductions NASA promised when development started. But if you divide the usual number of flights per year by the total costs, you come up with a figure of $ 245 million per year, significantly more than a Titan 4 or Proton launch with the same payload.

If the shuttle failed as a space truck, it succeeded in keeping the US in the manned spaceflight business in a period of low public interest and political support. With the excuse of delivering payloads to orbit, NASA got to fly up to seven astronauts and run a host of supplementary experiments and payloads with each flight.

With construction of the international space station beginning, NASA is looking forward to finally using the shuttle for its intended purpose. Due to the lower than planned flight rate, NASA’s contractors are confident they can keep the existing shuttles flying through 2030. The real test will come when (inevitably) another shuttle is lost.

	EDIN05	In February 1976 this version of the shuttle was proposed. A single liquid rocket booster under the external tank would replace the two solid rocket boosters....more.
	Boeing SDV	The Boeing SDV Class I vehicle would lead to the Shuttle-C, using the shuttle aft fuselage with SSME engines to power a cargo canister into orbit....more.
	Shuttle	The manned reusable space system which was designed to slash the cost of space transport and replace all expendable launch vehicles. It did neither, but did keep...more.
	IHLLV	Same concept as Shuttle C. Shuttle orbiter replaced by recoverable pod with shuttle main engines and payload cannister. Quick way for US to obtain heavy payload...more.
	Martin Marietta SDV	The Martin Marietta Class I SDV would lead to the Shuttle-C, using the shuttle aft fuselage with SSME engines to power a cargo canister into orbit....more.
	Shuttle LRB	Shuttle with Liquid Rocket Boosters in place of Solid Rocket Boosters....more.
	Shuttle II	In May 1988 NASA Langley studied a new-technology approach to improving the shuttle's payload capability. The design would allow 9,000 to 18,000 kg of additional...more.
	Low Cost Cargo Vehicle	This variant of the Shuttle C was envisioned for delivery of liquid hydrogen and liquid oxygen to orbit....more.
	Shuttle C	NASA Marshall design for a cargo version of the shuttle system. The shuttle orbiter would be replaced by an unmanned recoverable main engine pod. The same concept...more.
	Shuttle C Block II	In August 1989 NASA studied a version of the Shuttle-C with two Advanced Solid Rocket Mortors (ASRM's) in place of the standard RSRM's. This would increase the...more.
	Shuttle LRB 1989	In July 1989 a NASA Langley/George Washington University joint study was made of various Liquid Rocket Booster configurations....more.
	Ares Mars Direct	The Ares launch vehicle was designed for support of Zubrin's Mars Direct expedition. It was a shuttle-derived design taking maximum advantage of existing hardware....more.
	Shuttle Z	Shuttle-Z was Shuttle-C on steroids, the ultimate development of the shuttle to be used to put Mars expeditions into orbit. It would use 4 SSME's, and a third stage...more.
	Shuttle ASRM	Shuttle using Advanced Solid Rocket Motors (development cancelled 1993)....more.
	Shuttle ISS	Redesign of the shuttle with reliability in mind after the Challenger disaster reduced maximum payload to low earth orbit from 27,850 kg to 24,400 kg. When the...more.
	SRB CEV	Launch vehicle design preferred by NASA Administrator Mike Griffin to boost the manned CEV Crew Exploration Vehicle into low earth orbit. A single shuttle solid...more.
	Heavy Lift Carrier 2008	ATK Thiokol concept corresponding to earlier Shuttle-C proposals. The shuttle orbiter is replaced by a 6.5 m diameter x 25 m long cargo container, powered by two...more.
	Heavy Lift Carrier 2011	ATK Thiokol concept for a shuttle-derived heavy lift vehicle. The shuttle orbiter would be replaced by a 6.5 m diameter x 35 m long cargo container, powered by...more.
	Ares I	Shuttle-derived launch vehicle design selected by NASA Administrator Mike Griffin to boost the manned CEV Crew Exploration Vehicle into low earth orbit. A single...more.
	Heavy Lift Carrier 2015	ATK Thiokol concept for a shuttle-derived heavy lift vehicle with a lift equivalent to the Saturn V. The radical reconfiguration would put all elements in-line....more.
	Ares V	NASA baseline heavy-lift vehicle to renew manned lunar exploration by 2020....more.