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:
“The Mind in Infancy is, methinks, like the Body in Embrio, and receives Impressions so forcible, that they are as hard to be removed by Reason, as any Mark with which a Child is born is to be taken away by any future Application.”
—Richard Steele (1672–1729)
“The primary function of myth is to validate an existing social order. Myth enshrines conservative social values, raising tradition on a pedestal. It expresses and confirms, rather than explains or questions, the sources of cultural attitudes and values.... Because myth anchors the present in the past it is a sociological charter for a future society which is an exact replica of the present one.”
—Ann Oakley (b. 1944)
“What seems to us serious, significant and important will, in future times, be forgotten or won’t seem important at all.”
—Anton Pavlovich Chekhov (1860–1904)