NASA's space shuttles may be impressive examples of space engineering but they wouldn't get far without the extra boost provided by their solid rocket boosters (SRBs).

The largest solid rockets ever designed, NASA's shuttle SRBs are 12 feet (3.6 meters) wide and stand 149 feet (45.4 meters) tall upright. Each is capable of generating 2.65 million pounds of thrust during the first two minutes of a shuttle launch, after which they are jettisoned over the Atlantic Ocean and recovered by waiting ships for refurbishment and reuse.

In this image, engineers are wheeling the first of four SRB segments into NASA's massive Vehicle Assembly Building where it will be stacked on the Mobile Launch Platform in preparation for the agency's return-to-flight mission, STS-114 aboard shuttle Discovery. Slated to launch in spring 2005, Discovery flight is set to be the first mission to fly since NASA grounded its shuttle fleet after the loss of Columbia in 2003.

Once both right and left SRBs are assembled, engineers will install the large external tank, then finally attach Discovery and wheel the entire launch system out to the launch pad.

-- SPACE.com Staff

Credit: NASA

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