United Launch Alliance (ULA) has completed the preliminary design review for the dual-engine Centaur (DEC) upper stage, crucial to several commercial orbital spaceflight programmes.

The Centaur upper stage is normally powered by a single Rocketdyne RL-10, mounted atop the Atlas V launch vehicle. A second RL-10 was judged necessary to launch spacecraft with the safety considered necessary for human spaceflight.

Two commercial programmes, Boeing's CST-100 and Sierra Nevada's Dream Chaser, will use the Atlas V/DEC. Though the DEC was used in previous models of the Atlas, it has since been wholly displaced by the single-engine version. Though it remained an option for launch aboard Atlas V, the option has never before been exercised.

"The testing was successful and met all of the criteria," says George Sowers, ULA's vice president for human spaceflight. "The next major milestone from the DEC design is the critical design review."

The first spaceflight of the DEC is expected in 2017 with the first flight of either CST-100 or Dream Chaser, but several will be used for abort testing in the meantime.

The DEC is considered essential to making the Atlas V safe for people. Additional modifications, including monitoring and abort systems, will also be built and tested.

Source: Flight International