The launch takes place on a milestone date, marking 20 years since the STS-114 space shuttle mission took off from Kennedy Space Center Pad 39B. The launch of Discovery on the STS-114 mission on July 26, 2005, marked the return to flight for the space shuttle after the Columbia tragedy investigation.

SpaceX has lined up an evening launch from Cape Canaveral on Monday, but the threat of thunderstorms could force a delay.

Live updates from the July 21 late-countdown scrub of a SpaceX SES O3b mPOWER launch attempt from Cape Canaveral Space Force Station in Florida.

A power outage in the Santa Barbara area caused a major telecommunications disruption and forced the rescheduling of a planned SpaceX launch Tuesday afternoon. According to the Federal Aviation

Ax-4 is commanded by Axiom's director of human spaceflight and former NASA astronaut Peggy Whitson. Joining her are Shubhanshu Shukla of India, Sławosz Uznański-Wiśniewski from Poland, and Tibor Kapu, from Hungary. The three will be the first astronauts from each of their nations to launch on a mission to the ISS.

SpaceX had reset the countdown clock for its next human spaceflight, but a NASA decision has forced another delay of the private Axiom Space Ax-4 mission to the International Space