A last-minute technical problem has delayed Nasa’s unprecedented flight to the sun.
The launch countdown was halted with just one-minute, 55 seconds remaining, keeping the Delta IV (four) rocket at Cape Canaveral, Florida, with the Parker Solar Probe.
This followed earlier trouble in the countdown.
Nasa says it will try again on Sunday.
Once on its way, the Parker probe will venture closer to our star than any other spacecraft.
The mission is already a week late because of rocket issues.
Thousands of spectators gathered in the middle of the night to witness the launch, including the University of Chicago astrophysicist after whom the spacecraft is named.
Eugene Parker predicted the existence of solar wind 60 years ago. He is now 91 and eager to see the solar probe soar.