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:
“I am always glad to think that my education was, for the most part, informal, and had not the slightest reference to a future business career. It left me free and untrammeled to approach my business problems without the limiting influence of specific training.”
—Alice Foote MacDougall (1867–1945)
“The future is just as much a condition of the present as is the past. “What shall be and must be is the ground of that which is.””
—Friedrich Nietzsche (1844–1900)
“The future of humanity is uncertain, even in the most prosperous countries, and the quality of life deteriorates; and yet I believe that what is being discovered about the infinitely large and infinitely small is sufficient to absolve this end of the century and millennium. What a very few are acquiring in knowledge of the physical world will perhaps cause this period not to be judged as a pure return of barbarism.”
—Primo Levi (1919–1987)