SpaceX will try again to launch astronauts into space on Saturday evening, after the first attempt was cancelled because of bad weather.

Wednesday's flight was due to take Nasa astronauts Doug Hurley and Bob Behnken to the International Space Station (ISS).

The launch, which is taking place at 8.22pm BST (3.22 pm EDT), will be the first time that the US has flown its own astronauts to the ISS since Nasa's space shuttles were retired in 2011.

But Nasa chief Jim Bridenstine said his team weren't feeling the pressure on the second attempt, despite the aborted launch on Wednesday.

He told reporters: "We will launch when we are ready...

"I'll tell you, the President and the Vice President were proud of the Nasa team and the SpaceX team for making the right call for the right reasons [on Wednesday]."

The first attempt was cancelled with just 16 minutes to spare, with launch teams deciding that there was "too much electricity in the air".

Mr Bridenstine added: "There wasn't really a lightning storm or anything like that but there was a concern that if we did launch it could actually trigger one."

The weather forecast for the Florida launch on Saturday is also not particularly favourable.

CNN forecaster Haley Brink said: "Saturday and Sunday could turn out to have very similar weather as Wednesday did... We may be waiting on a game-time decision again this weekend."

And visibility will not be ideal for UK skywatchers on Saturday evening. The first appearance of the shuttle over the sky, at 8.40pm, will be too light, while the next time, at 10.15, the shuttle may be very low on the horizon.

If the flight goes ahead on Saturday evening, the astronauts will have a 19-hour flight to the ISS. They will stay in the space station for one-four months before coming back to earth.

This is the first time Nasa has worked with a private company to launch a shuttle into orbit.

SpaceX, owned by Elon Musk, has a $2.6 billion contract with Nasa to send six crew flights to the space station.