A launch abort engine built by Aerojet Rocketdyne is hot-fired during tests in the Mojave Desert in California. The engine produces up to 40,000 pounds of thrust and burns hypergolic propellants. The engines have been designed and built for use on Boeing’s CST-100 Starliner spacecraft in sets of four. In an emergency at the pad or during ascent, the engines would ignite to push the Starliner and its crew out of danger.