Boeing and NASA have completed the system requirements review (SRR) and system definition review (SDR) for the cryogenic stages of Space Launch System (SLS), the super-heavy launch vehicle designed to launch crewed flights into deep space.

Completing the reviews allows designers to finalise blueprints for the launch vehicle's components, after which fabrication will begin.

"SRR locks in requirements and serves as the basis for our estimates and performance metrics," says Chuck Hanes, Boeing SLS business manager. "The understanding we reach at SRR and SDR is a firm commitment to the rocket's requirements, design and resources."

The cryogenic stages include both upper and lower stage of the rocket, but do not include the externally-mounted boosters necessary to put the rocket in orbit with large payloads. Cryogenic fuels such as liquid hydrogen are often used on launch vehicles for their energy density, despite requiring extremely low temperatures.

The first SLS flight is scheduled for 2017, with a second scheduled in 2021.

Source: Flight International