Criticism of the Space Shuttle program costs through amortization. Development costs were expected to be recouped through frequent access to space. These claims were made in an effort to obtain budgetary funding from the United States Congress. Beginning in 1981, the space shuttle began to be used for space travel. However, by the mid-1980s the concept of flying that many shuttle missions proved unrealistic and scheduled launch expectations were reduced 50%. Following the "Challenger" accident in 1986, missions were halted pending safety review. This hiatus became lengthy and ultimately lasted almost three years as arguments over funding and the safety of the program continued. Eventually the
Space Shuttle program contractor for the program was North American Rockwell (later Rockwell International, now Boeing), the same company responsible for building the Apollo Command/Service Module. The contractor for the Space Shuttle Solid Rocket Boosters was Morton Thiokol (now part of Northrop Grumman Innovation Systems), for the external tank, Martin Marietta (now Lockheed Martin), and for the Space Shuttle main engines, Rocketdyne (now Aerojet Rocketdyne). The first orbiter was originally planned to be named "Constitution", but a massive write-in campaign from fans of the "Star Trek" television series convinced the White House to change the name to "Enterprise". Amid great fanfare, "Enterprise" (designated