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 the children and youth of a nation are afforded opportunity to develop their capacities to the fullest, if they are given the knowledge to understand the world and the wisdom to change it, then the prospects for the future are bright. In contrast, a society which neglects its children, however well it may function in other respects, risks eventual disorganization and demise.”
—Urie Bronfenbrenner (b. 1917)
“That children link us with the future is hardly news. . . . When we participate in the growth of children, a sense of wonder must take hold of us, providing for us a sense of future. Without the intimation of concrete individual futures, it is hardly worth bothering with social change and improvement.”
—Greta Hofmann Nemiroff (20th century)
“I have often inquired of myself, what great principle or idea it was that kept this Confederacy so long together. It was not the mere matter of the separation of the colonies from the mother land; but something in that Declaration giving liberty, not alone to the people of this country, but hope to the world for all future time. It was that which gave promise that in due time the weights should be lifted from the shoulders of all men, and that all should have an equal chance.”
—Abraham Lincoln (1809–1865)