Space Shuttle and StationThe wide range of
missions planned and conducted by the Shuttle program in pre-Challenger days,
as noted, has been narrowed following the disaster. During earlier flights, more than 30 satellites had been deployed for
scientific, commercial, and military purposes. This revenue-generating activity was widely billed as a justification of the program, but reimbursements never matched operational expenses. Most post-Challenger commercial launch contracts were abrogated unilaterally by NASA. However, many scientific research
missions remain on planned Shuttle schedules. Also, the capability for repairing and retrieving damaged spacecraft that was demonstrated by the Shuttle on earlier flights will remain available in the future. In addition, past Shuttle missions provided small amounts of extra cargo space or extra payload-lift capacity that usually was filled with small add-on packages, either from NASA, industry, or university laboratories, or from programs called the Getaway Special (GAS) and Student Experiments. These flexible and low-cost spaceflight opportunities will continue.Since 1984, when President Ronald Reagan directed NASA to build a permanently manned space station as its next major project, the program has evolved and been modified into a structure designed to support three to six astronauts in orbit. Several scientific modules and large amounts of electrical power are planned for the station. Plans also call for special Russian modules and significant participation by European, Canadian, Japanese, and Brazilian space organizations. The first sections of the structure are scheduled to be launched by about 1998, and up to 20 missions may be needed to assemble the station.