The second crewed spacecraft selected by NASA for its CCDEV program was Boeing's CST-100 Starliner, which like SpaceX's Dragon 2 spacecraft, will use a "pusher" launch escape system, consisting of four launch abort engines mounted on the service module that can propel the spacecraft away from its Atlas 5 launch vehicle in the event of an emergency on the pad or during ascent. The engines, which use hypergolic propellants and generate 40,000 pounds-force of thrust each, are provided by Aerojet Rocketdyne. The abort system was tested successfully during Starliner's pad abort test on November 4, 2019 at White Sands Missile Range.