Skywatchers in the UK should be able to see the International Space Station and the Crew Dragon capsule pass over the United Kingdom later.
The space station will pass over first, at around the time of launch. Then, the Crew Dragon, carrying Doug Hurley and Bob Behnken, will fly past around 25 minutes after lift-off (roughly 21:58 BST).
It’s a unique and historic opportunity to see them both before the rendezvous with the ISS some 24 hours later.
Some time after 13:00 EDT (17:00 GMT / 18:00 BST) we expect to see the astronauts walk out and get into cars for transportation to the launch pad.
The timing for today’s launch has to be precise. The Falcon 9 rocket must leave the ground at 16:33 EDT (20:33 GMT / 21:33 BST), or the astronauts won’t be able to catch the International Space Station (ISS) which passes overhead at 27,000km/h (17,000mph).
The rocket carrying Bob Behnken and Doug Hurley takes more than eight minutes to get to orbit. Once the Crew Dragon has separated, it makes the rest of the journey to the ISS using its own thrusters.
But one section of the rocket will touch down softly on a ship using engine power so that it can be re-used on a future flight. This is a SpaceX speciality that sets its Falcon apart from all other orbital rockets in use today.
For those interesting in keeping an eye out for it this evening it will be in the skies towards the South West of the UK, However NASA will live stream the event on Youtube should you wish to see how it looks closer up.