Blue Origin, the suspiciously quiet rocket company started by Amazon founder Jeff Bezos, fired up the thrust chamber for its engine at NASA’s Stennis Space Center in Mississippi.

The engine is a 100,000-pound thrust model that uses liquid oxygen and liquid hydrogen as fuel. Blue Origin plans on using the engines as part of its reusable booster system that will launch its interestingly shaped spacecraft into orbit as part of NASA’s Commercial Crew Development (CCDev) project. The Washington-based company is one of four upstart private space firms receiving funding for the development of a manned spacecraft that will be capable of carrying astronauts into orbit.