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Also totally dependent on the shuttle is the space station, which is to be assembled in orbit by astronauts with parts brought from earth by the shuttle. (It was originally scheduled to be placed in operation by 1992, but the target date has already slipped to 1994.) The station is designed to establish a permanent human presence in space. Men and women ferried to the station by shuttle and working aboard it for three months at a stretch are to carry out scientific and medical experiments and dabble in the space manufacture of drugs, crystals and alloys that might be best produced under conditions of weightlessness. The station is also supposed to serve as a base and staging area for future space missions, including a proposed manned flight to Mars. Any substantial delay in shuttle flights will almost certainly push back the day when a U.S. space station is orbiting the earth.
Delay could cause the most grief to the shuttle's biggest customer: the Pentagon. Though only two of the first 24 shuttle flights were fully dedicated to military purposes, the Pentagon was counting heavily on shuttles to carry out experiments for the Strategic Defense Initiative, as the Star Wars program is formally named, and to launch the satellites vital to modern warfare. Four of this year's shuttle missions were to be devoted to military uses, and the / Air Force had signed up to take a third of all shuttle flights beginning in 1988. Although some of the military satellites can be launched by expendable rockets, others--designed specifically to be handled by the shuttle--cannot. "We were on a tight schedule already," says an Air Force general. "Any delay cannot help being profoundly disruptive."
The backlog of flights that will build up before the shuttle flies again is certain to intensify competition among the military, commercial interests and scientists for space aboard the remaining three shuttles. The winner is likely to be the military, which has authority under an agreement with NASA to commandeer any shuttles that blast off. For example, the Pentagon deems it absolutely vital to lift into orbit a heavy KH-12 intelligence satellite, if not on its scheduled date of Sept. 29, then on the next available shuttle mission. A senior Pentagon official asserts that "when push comes to shove, national security interests will simply dictate that we flex our muscles and pre-empt shuttle space" on other flights too. Military priority on post- Challenger missions, in turn, will make the rivalry among would-be scientific and commercial users of the remaining flights all the more bruising.
The crunch could be softened by the building of another shuttle. Rockwell International's shuttle assembly line is still intact, and many existing shuttle spare parts could be used in building a new orbiter. But according to testimony last fall by Associate NASA Administrator Jesse Moore, another shuttle might not fly until 1991 or 1992; possibly that timetable could be shortened, but by how much is hard to calculate. Moreover, a new shuttle would cost around $2 billion.