Here is some more background on how this new system potentially improves things:

NASA uses highly combustible propellants: liquid hydrogen and liquid oxygen to power the RS-25 engines. These engines, along with solid rocket boosters, lift the rocket into orbit.

“When the engines start up on the launch pad, there is a small amount of free hydrogen that can potentially collect at the aft of the rocket,” said Don Nance, a Jacobs Technology Inc. employee in the Fluid Dynamics branch of the Engineering Directorate at Marshall. “About 10 seconds before liftoff, the igniters burn off that excess hydrogen rather than let it burn on its own, which could be a safety concern.”

Below are two videos one of they hydrogen test and one safety test video.

Keep up the good work NASA and we hope you enjoy the video!  And of course check back for updates as they come up with new tests.

thanks to NASA for the great info and pic