Boeing’s CST-100 Starliner spacecraft will fly on June 1 (Picture: Nasa/Joel Kowsky/EPA)
At 5.25pm today, Boeing will finally launch its Starliner spacecraft, despite a warning from a Nasa contractor that it could be potentially ‘catastrophic’.
The mission, which will carry two astronauts to the International Space Station (ISS), was planned for launch earlier this month but was scrubbed following the discovery of a leaky valve in a liquid oxygen tank as it prepared for launch.
That issue has been fixed, but a second valve has since been found to be leaking helium. The faulty valve helps control the craft in orbit.
However, Nasa, which is working alongside Boeing to launch the craft, said it did not need to fix the issue.
Nasa programme manager Steve Stich said: ‘We could handle this particular leak if that leak rate were to grow even up to 100 times.’
But not everyone is as confident. Erin Faville, president of Nasa contractor ValveTech, has urged Nasa to ‘re-double safety checks and re-examine safety protocols to make sure the Starliner is safe before something catastrophic happens.’
Speaking to MailOnline, Ms Faville said: ‘I warned. I will choose to let it play out.’
What is the Boeing Starliner?
The Boeing Starliner is a reusable spacecraft that has been designed to take crew to the ISS and on other low-orbit missions.
The US firm began working on its space capsule more than a decade ago, having won a contract from Nasa alongside SpaceX to develop a transport system for astronauts.
The spacecraft marks a new chapter for Boeing, which is also known for its aeroplanes and satellites.
The capsule, called CST-100, is around 15 feet in diameter, and has been designed to be used for up to 10 missions, holding a crew of up to seven people. It can remain docked to the ISS for around seven months.
The CST-100 Starliner in May 2022 (Picture: Nasa)
When is Starliner lifting off?
Starliner is due to launch on today at 5.25pm BST from Cape Canaveral in Florida, carrying the Nasa astronauts Butch Wilmore and Sunita Williams, who have both been to the ISS before.
The capsule will sit on top of an Atlas V rocket.
The two astronauts will stay aboard the ISS for a week before returning to Earth.
Why has the Starliner launch been delayed so many times?
Starliner was first set to launch in 2017 or 2018.
However, in October 2016, Boeing delayed the programme by six months, later extended extended, before the maiden voyage in 2019.
That was unsuccessful, after a software error stopped the capsule making it to the space station.
Boeing then attempted another uncrewed test flight, which also had issues, and led to the programme being delayed indefinitely in 2021.
However, by May 2022, the Starliner successfully launched an uncrewed mission to the ISS, which paved the way for the first crewed flight – scheduled for 2023.
This was pushed back after Boeing had issues with the parachute system and wiring harnesses.
The capsule was then scheduled to launch on May 6, 2024, but that attempt was delayed only two hours before liftoff due to an oxygen relief valve issue on the Atlas V rocket.
The Boeing Starliner has been delayed four times this month alone (Picture: Nasa/Joel Kowsky/EPA)
The decision was made to replace the valve, and the launch was rescheduled to May 12.
However, another issue arose when engineers found the helium leak.
How can I watch the Starliner launch?
Nasa will be live streaming the launch on its website as well as its YouTube channel, which can be seen below. Broadcast will begin around four hours before lift-off.
For those really interested in the mission, Nasa will also be showing the Starliner docking with the ISS on June 2.