NASA scientists hope they can successfully launch a rocket to the moon as soon as Friday, despite a failed attempt on Monday.
Test flight Artemis 1 was due to take off from Kennedy Space Center in Cape Canaveral, Florida during a two-hour window after 1:33 pm BST on Monday.
It was canceled by the launch director moments earlier due to a temperature problem in one of the engines.
Artemis mission manager Michael Sarafin said the team also encountered problems over the weekend and Monday, including lightning strikes and a fuel leak.
After the postponement of take-off, he told a NASA press conference that the team “is not ready to give up” and that the first possible half for the next attempt would be just before 1:00 pm BST on Friday.
Asked how realistic it is to expect another attempt so soon, Sarafin said: “Friday is definitely at stake.
“We really need time to go through all the information and we will play all nine innings here, we are not ready to give up yet.”
US Vice President Kamala Harris was among those at the space center awaiting takeoff on Monday, and NASA administrator Bill Nelson said she was “pumped all the time”.
Mr. Nelson told the press conference: “The Vice President was here.
“She was pumped the whole time.
“He’s very optimistic about our space program and this particular program of going back to the moon and going to Mars.”
The 322-foot (98m) tall Space Launch System (SLS) rocket, which is the world’s most powerful rocket to date, is expected to carry the Orion capsule, powered by the Airbus-built European Service Module (ESM) into the lunar orbit .
On the delayed launch attempt, Nelson said, “This is a brand new rocket.
“It won’t fly until it’s ready.
“There are millions of components in this rocket and its systems, and needless to say, the complexity is daunting when you put everything in the middle of a countdown.”
The flight, which will carry mannequins rather than astronauts, marks the next chapter in bringing humans back to the moon and is the first in NASA’s Artemis program.
There will be people on board for subsequent missions, with the first manned space flight scheduled for 2024.
The UK is part of the Artemis program, contributing to the Lunar Gateway – a space station currently under development with the European Space Agency – working together with the US, Europe, Canada and Japan.
British Space Agency Chief Executive Paul Bate said that when the rocket is finally launched “it will be wild”.
Writing on Twitter after the attempt on Monday, he said, “It’s not easy, this rocket science.
“But that’s the point, right… we’re pushing the boundaries of human knowledge and discovery.
“And when we launch, it will be wild.
“Forward to the Moon, Mars and beyond.”
Humans last reached the Moon about 50 years ago, and the latest mission is to prove that people can take longer and more sustainable journeys there.
It will also assess whether some infrastructure can be built on and around the Moon, allowing humans to survive on another planetary body.
The duration of the mission is 42 days, three hours and 20 minutes and in total it will cover 1.3 million miles.