Elon Musk’s SpaceX will try again on Thursday to launch its massive new rocket, Starship.
A frozen valve stopped an effort to fly the 120m-high vehicle on Monday, nine minutes before lift-off.
Airspace and ocean limitations have been reinstated to allow Starship to take flight from Texas’ east coast.
A 62-minute timeframe has been set aside beginning at 08:28 local time (13:28 GMT/14:28 BST) to get Starship up and running.
If it is successful, the new rocket system will be utilized to transport people and freight into orbit, to the Moon, and even to Mars.
Mr. Musk has attempted to keep expectations low for the test flight, which will take off from Boca Chica on the US-Mexico border.
“A win” would be simply getting the vehicle off the ground and without destroying the launch pad infrastructure, he said.
In February, this massive launcher, known simply as Super Heavy, was fired while still clamped to its launch station. However, its cluster of engines were throttled back to half its performance on that occasion.
If SpaceX goes for 90% thrust as stated on Thursday, the stage should provide something close to 70 meganewtons. This is equivalent to the force required to launch over 100 Concorde supersonic airliners into flight.
It also has twice the thrust of the Saturn V rocket, which famously delivered men to the Moon in the 1960s and 1970s.
The combined Starship rocket would fly over the Gulf of Mexico during the mission.
The plan is to launch the spacecraft on a near-orbital trajectory that will end with it splashing down in the Pacific, a few hundred kilometers north of Hawaii.
Super Heavy, which is responsible for the first two minutes and fifty seconds of flight, will attempt to return close to the Texas coast once its lifting mission is completed.
It will be instructed to hover vertically just above the Gulf of Mexico before being allowed to collapse over and sink.
Although both segments will end the day on the seafloor, the ultimate goal is to have both halves of the vehicle perform controlled landings so they can be refuelled and reused, repeatedly.
How long it will take to achieve this capability is anyone’s guess. But if the project is successful, it would be transformative.
The prospective payload performance to orbit of more than 100 tonnes a flight, allied to the low cost of operation – principally, just the cost of fuel – should open the door to an exciting future.
“We’ve got an arduous two or three years ahead of us with, probably, you know, many bumps on the road, but at the end of that, we should have something that enables a base on the Moon and a base on Mars,” Mr Musk said this week.
The entrepreneur will initially use Starship to launch thousands more satellites for his broadband internet constellation in the sky – Starlink.
Only when engineers are confident in the vehicle’s reliability will they permit people to fly on the rocket.
The first mission has already been lined up. It will be commanded by billionaire US businessman and fast-jet pilot Jared Isaacman. He’s already flown to space in a SpaceX Dragon capsule.
The first flight around the Moon will be conducted by Japanese retail fashion billionaire Yusaku Maezawa. He will take eight artists with him as part of his DearMoon project.
The US space agency, Nasa, wants to use a version of Starship to land its astronauts on the Moon’s surface.