The USAF Space and Missile Systems Center released a formal request for proposals on June 2, seeking prototype ideas for new rocket engine systems. The RFP is part of the service’s plan to wean itself off of the Russian-produced RD-180 engine, which is used on United Launch Alliance’s Atlas V rocket, and establish a domestic launch market. USAF will award a “portfolio of investments” on a rolling basis in as many as four “rocket propulsion system” solutions, each of which will last between 12 and 18 months, and will build a foundation for establishing competitive domestic launch systems and secure launch service commitments, states the release. At the same time, USAF will continue competing launch service contracts to “certified providers who demonstrate the capability to design, produce, qualify, and deliver launch systems and provide the mission assurance support required to deliver national security space satellites to orbit,” the announcement states. USAF certified SpaceX for national security space launches, after a two-year review period, late last month. SMC Commander Lt. Gen. Samuel Greaves said the goal is to have two or more domestic commercially viable launch providers to meet National Security Space needs, which he said is “essential in order to solidify US assured access to space, transition the [Evolved Expendable Launch Vehicle] program away from strategic foreign reliance, and support the US launch industry’s commercial viability in the global market,” he said.