Photos: More shots of Delta 4 liftoff

NASA has placed an order with Boeing for the first operational mission to ferry a crew to the International Space Station in a new era of commercial human spaceflight.

Spaceflight Now members can watch a live view of Cape Canaveral’s Complex 41 launch pad as an Atlas 5 rocket counts down to liftoff at 5:02 p.m. EST (2202 GMT) Thursday with the GOES-S weather satellite.

The launch of a NASA research satellite built to probe conditions along the boundary between Earth’s atmosphere and space has been tentatively rescheduled for no earlier than Wednesday, pending the conclusion of a review of unexpected data signatures discovered on the first stage of the mission’s air-launched Pegasus XL rocket.