NASA's next-generation J-2X rocket engine is ready for a second phase of testing, following a successful round of tests last year. The space agency is developing the engine to power its Space Launch System (SLS) rocket, which is intended to enable deep-space exploration and experimentation. Alongside SLS, NASA is developing the Orion Multi-Purpose Crew Vehicle which will enable astronauts to head into space for up to 21 days.

The J-2X is a reboot of the J-2 engine that powered the Apollo Program of the 60s and 70s, and will be the first new liquid oxygen and liquid hydrogen rocket engine developed in 40 years. The new set of tests will simulate the high-altitude, low pressure conditions the engine will have to cope with in real-world situations, and are tentatively scheduled to begin this Wednesday. NASA hopes that the J-2X will complete this testing phase by the end of the year, with overall manufacturing set to be finished in time for SLS's launch in 2017.