Watch Live: Boeing's Starliner crew capsule launches to space station in make-or-break flight

Keeping an eye on threatening weather, engineers readied a United Launch Alliance Atlas 5 rocket for blastoff Tuesday on a make-or-break flight to boost Boeing's Starliner crew capsule into orbit for an unpiloted trip to the International Space Station. The launching comes 18 months after Starliner software errors derailed a 2019 test flight.

Boeing is counting on the test flight to finally clear the way for piloted missions that will eventually ferry astronauts to and from the station under a $4.2 billion commercial crew contract with NASA. The countdown began at 2 a.m. ET, ticking toward liftoff from pad 41 at the Cape Canaveral Space Force Station at 1:20 p.m. ET. The launch was initially planned for last Friday, but NASA ordered a delay while Russian space station engineers resolved problems with a newly arrived laboratory module.