(REUTERS) - Nasa engineers successfully tested a powerful new rocket engine on Thursday (August 18), moving one step closer to the development of the Space Launch System (SLS), meant to carry humans deeper into space than ever before, including a mission to Mars.

Spectators watched from nearby bleachers as the engine of the RS-25 powered into life at Nasa's Stennis Space Center, near Bay St. Louis, Mississippi.

SLS will rely on two rocket boosters as well as the RS-25, one of four "modified space shuttle main engines that will help lift the huge SLS rocket off the ground", according to the Nasa website.

The RS-25s are fueled by liquid hydrogen and liquid oxygen. Together, the four RS-25s will generate 2 million pounds of thrust.

During the firing, the test team put the RS-25 engine, among the most proven in the world, through a variety of changing conditions, including temperature and pressure changes, to see if the modernised versions will hold for SLS.

Nasa conducted a series of developmental tests on the engine last year before testing a flight engine that will be used on its second test flight, known as Exploration Mission-2 (EM-2), according to Nasa.