Live coverage: Kennedy Space Center to reopen Friday

The mission launched the first two of six Earth observation satellites built by Maxar Space Systems. Liftoff from Space Launch Complex 4 East happened at 11:36 a.m. PDT (2:36 p.m. EDT, 1836 UTC).

The 100th rocket in America’s Evolved Expendable Launch Vehicle program, the current fleet of boosters used by the nation to get its critical assets into space, was rolled to the pad Friday morning for a vital mission on Saturday.

United Launch Alliance teams loaded super-cold liquid hydrogen and liquid oxygen into an Atlas 5 rocket Friday at Cape Canaveral during a countdown dress rehearsal for a planned launch next month with the Solar Orbiter mission, a robotic spacecraft to study the origins of the solar wind and image the sun’s poles for the first time.