Update: NASA has postponed the spacewalk due to a "medical concern with a crew member." NASA did not identify the astronaut, nor share details about the medical issue. A new date for the spacewalk has not been announced.

A Falcon 9 rocket carrying about 40 payloads, including NASA's Pandora exoplanet satellite, is scheduled to lift off from California's Vandenberg Space Force Base during a 57-minute window that opens at 8:19 a.m. EST (1319 GMT and 5:19 a.m. local California time).