Officials deemed the weather to be unsafe for liftoff with just 16 minutes left on the countdown.
The culprit: the “strength of electric fields in the atmosphere” was deemed too high in the nearby skies.
“Unless you can give us another 10 minutes (beyond T-0) we’re not going to get there today,” a SpaceX official could be heard on NASA’s official stream. But a hard 4:33 pm “instantaneous launch window” meant the entire launch had to be delayed.
NASA and SpaceX have set alternative launch windows for 3:22 pm EDT on Saturday, May 30, and 3 pm EDT on Sunday, May 31.
Launching astronauts requires the weather at the launch site to be clear enough for takeoff, and for ocean waters at multiple possible splashdown sites to also be calm.
The news comes shortly after SpaceX retracted the crew access arm and started fueling its Falcon 9 rocket.
That’s to ensure that NASA astronauts Bob Behnken and Doug Hurley, who will be on board SpaceX’s Crew Dragon spacecraft, can be recovered safely if they need to make an emergency landing.