This is a continuation of their statement about the test.  They just fired this thing up a few days ago:

“What a great moment for NASA and Stennis,” said Rick Gilbrech, director of NASA’s Stennis Space Center in Bay St. Louis, Mississippi. “We have exciting days ahead with a return to deep space and a journey to Mars, and this test is a very big step in that direction.”

The hot fire marked the first test of an RS-25 flight engine for NASA’s new Space Launch System (SLS), being built to carry humans on future deep-space missions, including an asteroid and Mars. Four RS-25 engines will help power the SLS core stage.

Aside from the technology to send astronauts into deep space, they also have to focus on the conditioning of the men and women as well.  It is one thing to focus on the propulsion and the other task is to make sure it is a decent environment for the astronauts.

thanks to NASA for the great info

thanks to space.com for the great info