ATK has reached preliminary design review (PDR) on the solid rocket boosters intended to help launch the Space Launch System (SLS).
The solid rocket boosters, direct descendents of those used to power the now-retired Space Shuttle, will be used to get SLS through the thickest part of the atmosphere before detaching. Though not always employed, they are planned for use with some of the heaviest loads.
Though they will be used for the SLS's 2017 first flight, they will be replaced by an as-yet unselected advanced booster by the second flight in 2021. ATK is among the competitors for the advanced booster with a new solid rocket booster, as are Aerojet and Rocketdyne with liquid-fueled designs.
"With the successful completion of PDR, the SLS booster design can now proceed with the associated activities required to advance the design toward critical design review (CDR)," says the company. "Additionally, a ground static firing of qualification motor-1 is planned for later this year at ATK."
SLS is intended to launch Lockheed's Orion crew capsule on interplanetary missions.