Posted: Sat, May 12, 2018, 6:11 PM ET (2211 GMT)
United Launch Alliance announced Friday that it will use the RL10 engine from Aerojet Rocketdyne for its Vulcan upper stage. ULA said it selected the RL10 in a "competitive procurement" that likely also included Blue Origin's BE-3U. The decade-long deal also includes an agreement to cooperate on the development of a next-generation version of the engine, known as the RL10C-X. ULA has yet to make a decision on which engine will power the first stage of Vulcan, weighing Aerojet's AR1 versus Blue Origin's BE-4, but said a decision would come "soon."
