Future
Designers look to more economical and reliable launch systems for the future, with lower maintenance and operational costs. One approach is Single Stage To Orbit (SSTO), which would be 100% reusable and use a single stage. NASA evaluated several concepts in the 1990s, and selected the X-33, which would eventually have been the VentureStar. During design that program increased in complexity and development cost, encountered problems and was finally cancelled.
A variant of SSTO is a hypersonic, scramjet-powered, airbreathing vehicle. This would be launched and landed horizontally like an airliner. It would achieve much of orbital velocity while still within the upper atmosphere. It was originally investigated by the U.S. Department of Defense, but passenger-carrying civilian versions were planned. The official name was the Rockwell X-30. Like the X-33, the X-30 development encountered major technical difficulties, primarily due to the system complexity and materials required for hypersonic flight, and was also canceled.
Another approach is lower-cost expendable launch vehicles. NASA currently uses commercial ELVs for unmanned launches, and could use commercial ELVs for future manned launches. This would fit with NASA's mandate to promote commercial access to and use of space. The Commercial Orbital Transportation Services program began in 2006 with the purpose of creating commercially operated unmanned cargo vehicles to service the ISS. The SpaceX Dragon became operational upon launching and docking with the ISS in May 2012. The Orbital Sciences' Cygnus is expected to become operational in 2012. The Commercial Crew Development (CCDev) program was initiated in 2010 with the purpose of creating commercially operated manned spacecraft capable of delivering at least four crew members to the ISS, to stay docked for 180 days and then return them back to Earth. These spacecraft are expected to become fully operational in the mid-2010s. In August 2012, NASA announced funding agreements with three firms, SpaceX, Boeing and Sierra Nevada Corporation, for development of crew delivery capability.
Read more about this topic: Criticism Of The Space Shuttle Program
Famous quotes containing the word future:
“If ever the search for a tranquil belief should end,
The future might stop emerging out of the past,
Out of what is full of us; yet the search
And the future emerging out of us seem to be one.”
—Wallace Stevens (1879–1955)
“When we raise our children, we relive our childhood. Forgotten memories, painful and pleasurable, rise to the surface.... So each of us thinks, almost daily, of how our own childhood compares with our children’s, and of what our children’s future will hold.”
—Richard Louv (20th century)
“Autonomy means women defining themselves and the values by which they will live, and beginning to think of institutional arrangements which will order their environment in line with their needs.... Autonomy means moving out from a world in which one is born to marginality, to a past without meaning, and a future determined by others—into a world in which one acts and chooses, aware of a meaningful past and free to shape one’s future.”
—Gerda Lerner (b. 1920)