First hotfire of our BE-4 engine is a success #GradatimFerociter pic.twitter.com/xuotdzfDjF

— Blue Origin (@blueorigin) October 19, 2017

After more than five years of development, Blue Origin has successfully completed a hot-fire test of its liquid natural gas-powered BE-4 rocket engine. Blue Origin Chief Executive Officer (CEO) Jeff Bezos’ grand scheme is to use the engine on United Launch Alliance’s Vulcan rocket — so how will Aerojet Rocketdyne, which is also jockeying to equip the Vulcan, respond?

Read more at Ars Technica.