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The most powerful rocket ever developed will attempt a maiden launch on Monday.
The vehicle, known as Starship, was built by American entrepreneur Elon Musk’s SpaceX company.
It is nearly 120m (400ft) tall and is designed to have nearly double the thrust of any rocket in history.
SpaceX will attempt to lift off the spacecraft in an unmanned demonstration from Boca Chica, Texas at 08:20am local time (1:20pm GMT; 2:20pm BST).
The goal is to send the vehicle’s upper stage eastward, to nearly complete a trip around the globe.
Mr. Musk has called on everyone to temper their expectations. It is not uncommon for a rocket to experience some type of failure during its initial exit.
“It’s the first launch of a very complicated and gigantic rocket, so it may not launch. We’ll be very careful and if we see anything that worries us, we’ll postpone the launch,” he told a Twitter Spaces event.
“If we launch, I would consider anything that doesn’t involve destroying the launch pad itself a victory.”
Thousands of spectators packed coastal resorts on the Gulf of Mexico to watch the event. SpaceX is running a live stream on its YouTube channel.
Elon Musk hopes to completely turn the rocket business upside down with Starship.
It is designed to be completely and quickly reusable. Imagine flying people and satellites into orbit several times a day the same way an airliner might cross the Atlantic.
In fact, he believes the vehicle could usher in an era of interplanetary travel for ordinary humans.
Starship’s upper stage has been tested on short jumps before, but this will be the first time it has ascended with its lower stage.
This gigantic booster, called simply Super Heavy, launched while docked in its launch pad in February. However, the engines on that occasion were reduced to half their capacity.
If, as promised, SpaceX aims for 90% thrust on Monday, the stage should deliver something close to 70 meganewtons. This is equivalent to the force needed to propel nearly 100 Concorde supersonic airliners into takeoff.
Assuming all goes as planned, Starship will ascend and head downwards across the Gulf, the 33 engines on the bottom of the methane-fueled booster burning for two minutes and 49 seconds.
At that point, the two halves of the rocket will separate and the upper section, the ship, will continue on its own engines for another six minutes and 23 seconds.
At this point, it should travel over the Caribbean and float in space more than 100km above the planet’s surface.
SpaceX wants the Super Heavy booster to try to return near the Texan coast and descend vertically, to hover just above the waters of the Gulf. It will then be allowed to capsize and sink.
The vessel aims to re-enter Earth’s atmosphere after nearly one complete revolution of the Earth, descending into the Pacific just north of the Hawaiian Islands. It has been fitted with protective tiles to deal with the immense heating it will experience on the way down. An ocean somersault is scheduled to occur 90 minutes after liftoff.
Long term, SpaceX expects both booster and ship to make controlled landings so they can be refueled and relaunched.
The company experimented with different approaches to building steel vehicles in Boca Chica.
There are various models waiting for their turn to take flight.
One of the most interested spectators on Monday will be the American space agency, NASA.
He’s giving SpaceX nearly $3 billion to develop a variant of Starship that should land astronauts on the Moon.
Garrett Reisman, a professor of astronautical engineering at the University of Southern California, says Musk has ambitions to go even deeper into the Solar System.
“He sees Starship as potentially another giant paradigm shift, an incredible increase in capability – the ability to really get people on a massive scale to Mars,” the SpaceX consultant and former astronaut told BBC News.
“There are a lot of potential benefits, but there are also a lot of potential risks because it’s very difficult. No one has ever built a rocket that big, twice the size of the closest thing.”
