WORLD Updated: Aug 11, 2018 17:36 IST

Rocket maker United Launch Alliance said it would try again Sunday, provided the helium-pressure issue can be resolved quickly

NASA has said that the launch was “scrubbed” and a second attempt will be made on Sunday morning.(NASA Twitter)

With just one minute, 55 seconds remaining for NASA’s Parker Solar Probe to lift off, the launch controller shouted, “Hold, hold, hold.”

Reason: The red pressure alarm for the gaseous helium system had gone off.

Rocket maker United Launch Alliance said it would try again Sunday, provided the helium-pressure issue can be resolved quickly.

Engineers are taking utmost caution with the $1.5 billion Parker Solar Probe, which Thomas Zurbuchen, head of NASA’s science mission directorate, described as one of the agency’s most “strategically important missions.”

NASA wrote on its Twitter page that the launch was postponed from 3:33 am ET to 4:38 am ET. It later updated that the launch was “scrubbed” and a second attempt will be made on Sunday morning.

Thousands of spectators gathered in the middle of the night to witness the launch, including the University of Chicago astrophysicist for whom the spacecraft is named. Eugene Parker predicted the existence of solar wind 60 years ago. He’s now 91 and eager to see the solar probe soar.