The space agency decided years ago against buying seamless solid rocket boosters for the shuttle that would have "precluded potential failure" associated with joints and seals because the segmented rockets offered by Morton Thiokol Inc. were cheaper, according to a 1973 NASA document.
The monolithic design was proposed by Aerojet General of California, one of the world leaders in propulsion systems, and the company planned to build the rockets as single units at its facility on the South Florida coast and barge them up to the Kennedy Space Center on Cape Canaveral.
But while the "inherent advantages were clearly recognized" by the National Aeronautics and Space Administration, the contract went to Morton Thiokol even though the Utah company "trailed in technical areas," according to the report. Morton Thiokol, the report states, "would give the agency the lowest funding requirements."
Awarding the contract to any of the other three bidders could "give rise to an additional cost of appreciable size," the report states. The report does not give specific estimates of savings.
The possible failure of a joint on the Challenger's right booster is the leading suspect in the Jan. 28 explosion that destroyed the vehicle and killed all seven persons on board. The boosters supplied by Morton Thiokol use steel rocket casings that are made up of four segments that are bolted together at the Kennedy Space Center.
Officials at Aerojet General declined to comment on the report, and they would not discuss their proposal to build the boosters as single units, but some engineers who are no longer associated with the company are sharply critical of the decision to build the rockets in reusable segments.
Werner Kirchner, a former vice president of Aerojet General who headed that company's solid rocket program for many years, said in an interview that the decision to build the boosters in segments was a serious error.
"I wouldn't build a rocket the way that one was built," Kirchner said, shaking his head. Kirchner pioneered in the development of rockets for the Defense Department. "They wouldn't have let me build a propulsion system like that for all the tea in China," he said.
Aerojet General built Titan ICBMs for the Air Force and Polaris ballistic missiles for the Navy as well as a wide range of liquid- and solid-fueled rockets. But while it ranked itself as the world's largest builder of rockets, it lost out early in the competition to build the boosters for the shuttle.
That is in spite of the fact that the evaluation from NASA praised the proposal from Aerojet General, particularly the "monolithic design" that would have housed the entire rocket in a single casing. That design, the report states, "precluded potential failure modes associated with joints and seals and thus contributed to a highly reliable design."
The decision to use segmented rockets left NASA in the position of trying to come up with a new technology while holding down costs, Kirchner said.
"They were looking for what I call an off-the-shelf technological breakthrough," he added.
In the "selection statement" justifying the decision to award the contract to Morton Thiokol, dated Dec. 12, 1973, NASA eliminated Aerojet General from among four bidders because "it ranked significantly lower in the mission suitability evaluation," an apparent reference to potential delays and rising costs from the company's plans to begin production in California and later move to Florida.
Several sources familiar with the problems of those early days of the shuttle program said NASA was concerned about the "logistics" involved in shipping the huge rockets in one piece.
Aerojet General planned eventually to move its shuttle operation to a large site it had purchased in southern Florida adjacent to the Everglades National Park. From the Florida plant, the assembled rockets were to be shipped up the coast to the Kennedy spaceport, a plan NASA applauded because of its "low cost, safe shipment via water."
But to start production in California and then move to Florida "created the lowest overall score in mission suitability" among the four bidders, the report states.
'Low Labor Costs'
Morton Thiokol, on the other hand, could begin immediate production of segmented rockets at its plant in Utah and would not need to build additional production facilities in Florida. The report notes that Morton Thiokol would benefit from "low labor costs" at its Utah plant, even though there was "some early risk because of a lack of experience (in building nozzles)." But since it already had the facilities needed to build the rockets, NASA concluded that "any selection other than Thiokol would give rise to an additional cost of appreciable size," the report noted.
Although Aerojet was eliminated early in the competition, the remaining three bidders--Morton Thiokol, Lockheed Missiles & Space Co. and United Technologies Corp.--were judged a "standoff" in NASA's evaluation.