Shuttle-Derived Launch Vehicle

Shuttle-Derived Launch Vehicle, or simply Shuttle-Derived Vehicle (SDV), is a term describing one of a wide array of concepts that have been developed for creating space launch vehicles from the components, technology and infrastructure of the Space Shuttle program. SDVs have also been part of NASA's plans several times in the past. In the late 1980s and early 1990s, NASA formally studied a cargo-only vehicle, Shuttle-C, that would have supplemented the crewed Space Shuttle in orbiting payloads.

In 2005, NASA decided to develop the Ares I and Ares V launch vehicles, based in part on highly modified Shuttle components to replace the Space Shuttle, and enable exploration of the Moon and Mars. The agency also studied a third such vehicle, the Ares IV. As of April 2011, NASA's replacement vehicle for the Space Shuttle is an SDV, the Space Launch System and multiple commercial vehicles. Over the course of the 2010 two different commercial vehicles were developed that use man-rated heavy lift launcher. In the meantime NASA has continued to use the Russian Soyuz, which it also used during the Shuttle program as part the International Space Station program

SDV concepts were proposed even before the Shuttle itself began flying. Proposed SDV concepts have included:

Several such concepts are of particular note:

Beginning in 1987, NASA actively pursued development of a vehicle called the Shuttle-C, an uncrewed cargo-only launch vehicle. Shuttle-C would have replaced the winged Space Shuttle Orbiter with an expendable cargo module. The module would have no wings, would not carry crew, and would not be recovered. It was expected to carry up to 150,000 pounds (68,000 kg) of payload to low-Earth orbit, compared to the Shuttle's nominal maximum of 65,000 pounds (29,000 kg). Budget pressures, caused in large part by the Space Station Freedom project, resulted in the official cancellation of Shuttle-C in 1990.

The National Launch System was a study authorized in 1991 by President George H. W. Bush to outline alternatives to the Space Shuttle for access to Earth Orbit. The largest of three proposed vehicles was designated NLS-1 and used for its core stage a modified Space Shuttle External Tank with four Space Transportation Main Engines (STMEs) attached to the bottom of the tank. A payload or second stage would fit atop the core stage, and two detachable Solid Rocket Boosters would be mounted on the sides of the core stage. Larger rockets than NLS-1 were contemplated, using multiples of the NLS-1 core stage.

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