SpaceX’s Falcon 9 rocket took off Monday from Vandenberg Air Force Base in California with 10 new satellites for Iridium’s upgraded communications network in low Earth orbit.

European engineers test-fired the world’s most powerful present-day single-segment solid rocket booster Monday in French Guiana, clearing a major development hurdle for the Vega-C and Ariane 6 launchers set for debuts in 2019 and 2020.

Culminating years of construction and testing, a $1.2 billion satellite designed to spot and track enemy missiles threatening the United States homeland, its deployed military forces abroad or allied nations will ascend to a surveillance post in space Thursday.