NASA has delayed giving the green light to SpaceX’s historic mission to fly astronauts to the International Space Station (ISS), with less than a week to go before its scheduled launch date.
Next Wednesday’s mission will be the first human spaceflight to launch from American soil since 2011, when NASA‘s space shuttle fleet was retired.
Since then, its astronauts have only be able to fly to the ISS from the Baikonur Cosmodrome in Kazakhstan, using expensive Russian Soyuz rockets costing up to $86m (£70m) per seat.
As part of NASA’s commercial crew programme, two US-based companies – Elon Musk’s SpaceX and Boeing – are going to return this human spaceflight capability to American soil with far cheaper seat costs.
It will cost $55m (£45m) for SpaceX and $70m (£57m) for Boeing.
However, NASA’s flight readiness review – which was set to deliver the final go-ahead for the SpaceX launch – did not conclude as expected on Thursday.
The agency instead announced discussions were still ongoing, although the details were not disclosed.
For now the launch is still scheduled to proceed next Wednesday, 27 May, at approximately 9.30pm UK time, with a virtual press conference in Florida set to be held on Friday following the conclusion of the review.
Two NASA astronauts, Bob Behnken and Doug Hurley, are due to fly to the ISS in SpaceX’s Crew Dragon spacecraft, launched on top of one of the private spaceflight company’s specially instrumented Falcon 9 rockets.
US President Donald Trump told reporters at the White House he was thinking about flying to Florida to watch the launch, joking: “I’d like to put you all on the rocket and get rid of you for a while.”
The astronauts will be accelerated to approximately 17,000mph (27,000kmph) – 22 times the speed of sound – and put on an intercept course with the ISS.
After about 24 hours in orbit, the Crew Dragon will rendezvous and dock with the space station.
Although the spacecraft is designed to do this autonomously, the astronauts onboard both the Dragon and the ISS will be ready to take manual control if necessary.
Mr Behnken is an experienced astronaut, having been selected by NASA in 2000 after a career as a flight test engineer with the US Air Force.
He has two space shuttle flights under his belt and six spacewalks.
Mr Hurley was also selected as an astronaut in 2000 after a career as a fighter pilot and test pilot in the Marine Corps, and has completed two spaceflights – including the final space shuttle mission in July 2011.