UPDATE: NASA to Discuss, Broadcast Booster Test for Space Launch System Rocket

The booster for the world's most powerful rocket, NASA's Space Launch System (SLS), which will power the agency's astronauts on the journey to Mars, will fire up for a major ground test at 10:05 a.m. EDT (8:05 a.m. MDT) Tuesday, June 28, at Orbital ATK Propulsion Systems' test facilities in Promontory, Utah.