An engineering board has cleared the first element of NASA’s heavy-lift Space Launch System (SLS) for preliminary manufacturing, keeping the big new government-owned rocket on track for a first flight with the Orion multipurpose crew vehicle in 2017.

In a preliminary design review Dec. 20 at Marshall Space Flight Center, which manages SLS development, the review board of experts in propulsion and vehicle design from industry and NASA determined the SLS core stage design met requirements “within acceptable risk” and could meet schedule and budget constraints, NASA said.

The review also determined that the core stage design can be integrated safely with the surplus RS-25D space shuttle main engines NASA has set aside for the early SLS flights; the five-segment shuttle-derived solid-rocket boosters that will power it off the launch pad, the Orion capsule and the launch facilities planned for it at Kennedy Space Center.

“Each individual element of this program has to be at the same level of maturity before we can move the program as a whole to the next step,” stated SLS Program Manager Todd May. “The core stage is the rocket’s central propulsion element and will be an optimized blend of new and existing hardware design. We’re building it with longer tanks, longer feed lines and advanced manufacturing processes. We are running ahead of schedule and will leverage that schedule margin to ensure a safe and affordable rocket for our first flight in 2017.”

The review board’s decision allows Boeing’s Exploration Launch Systems unit in Huntsville, Ala., the core stage prime contractor, to continue modifications at NASA’s Michoud Assembly Facility in New Orleans, where the stage will be built in facilities that also produce the space shuttles’ external tanks. Boeing also holds the contract for the core stage avionics.

“Passing a preliminary design review within 12 months of bringing Boeing on contract shows we are on track toward meeting a 2017 launch date,” stated Tony Lavoie, manager of the SLS Stages Element at Marshall. “We can now allow those time-critical areas of design to move forward with initial fabrication, and proceed toward the final design phase — culminating in a critical design review in 2014 — with confidence.”

First flight of the SLS in its 70-metric-ton-lift variant is scheduled to carry an unmanned Orion beyond the Moon. The first crewed flight is scheduled in 2021. NASA is also backing early studies for advanced boosters that would take the deep-space human exploration launcher’s lift capacity up to the congressionally mandated 130 metric tons.