SpaceX – the American space exploration company owned by Elon Musk – will make a second try at launching the most powerful rocket ever made today, after calling off the initial attempt on Monday.
The giant rocket called Starship was set to take off from the SpaceX facility in Boca Chica, Texas but could not launch due to a “frozen valve”.
Before liftoff, Mr Musk said on Twitter that “a pressurant valve appears to be frozen, so unless it starts operating soon, no launch today”. The valve did not start operating, so the launch was called off.
Here’s when the launch is scheduled today, how to watch, and everything else you need to know.
When is the SpaceX launch today?
The launch is scheduled to take place between 8.28am and 9.30am local time, which is between 2.28pm and 3.30pm in the UK.
However, the specific timings of the launch are “dynamic and likely to change” – “as is the case with all developmental testing”, SpaceX said.
Mr Musk tweeted on Thursday morning: “All systems currently green for launch.”
There will be a live stream of the launch here on this page, starting from 1.45pm. It is also being streamed live on the SpaceX YouTube channel.
What should we expect from the launch?
The test mission – whether or not its objectives are entirely met – represents a key milestone in SpaceX’s ambition of sending humans back to the Moon and ultimately to Mars – also the central goal of a renewed Nasa spaceflight programme intended to integrate the Starship.
But SpaceX faces enormous challenges in merely launching a spacecraft that would instantly become, if it successfully gets off the ground, the most powerful rocket on Earth.
Both the lower-stage Super Heavy booster rocket and the upper-stage Starship cruise vessel it will carry to space are designed as reusable components, capable of flying back to Earth for soft landings – a manoeuvre that has become routine for SpaceX’s smaller Falcon 9 rocket.
But neither stage will be recovered for the expendable first test flight to space, expected to last no more than 90 minutes.
Prototypes of the Starship cruise vessel have made five sub-space flights up to six miles above Earth in recent years, but the Super Heavy booster has never left the ground.
In February, SpaceX did a test-firing of the booster, igniting 31 of its 33 Raptor engines for roughly 10 seconds with the rocket bolted in place vertically atop a platform.
The Federal Aviation Administration just last Friday granted a licence for what would be the first test flight of the fully-stacked rocket system, clearing a final regulatory hurdle for the long-awaited launch.
If all goes as planned, all 33 Raptor engines will ignite simultaneously to loft the Starship on a flight that nearly completes a full orbit of the Earth before it re-enters the atmosphere and free-falls into the Pacific at supersonic speed about 60 miles off the northern Hawaiian islands.
After separating from the Starship, the Super Heavy booster is expected to execute the beginnings of a controlled return flight before plunging into the Gulf of Mexico.
Starship’s blazing re-entry over the Pacific will test its ability to aerodynamically steer itself using large flaps and for its heat shielding to withstand the intense friction generated as it plummets through the atmosphere.
“The ship will be coming in like a meteor,” Mr Musk said. “This is the first step in a long journey that will require many flights.”
Additional Super Heavy boosters were already on deck in Boca Chica for future test flights, he added.
As designed, the Starship rocket is nearly two times more powerful than Nasa’s own Space Launch System, which made its debut uncrewed flight to orbit in November, sending a Nasa cruise vessel called Orion on a 10-day voyage around the moon and back.
