Where are they flying and how long will it take?published at 13:55 British Summer Time 10 August 2023
The launch window opens at 08:30 local time (15:30 BST) for the VSS Unity to take off from from New Mexico in the US.
The rocket will be carried on the first stage of its journey on board a carrier plane, known as Eve.
It will then aim to ignite its engine and travel to an altitude of 279,000ft (85km). This is considered to be "space" by US government agencies.
Those on board will briefly experience weightlessness at the peak of their trip - which is estimated to last about 90 minutes.
Virgin Galactic's second commercial flight (its first for tourists) will then glide back to base at Spaceport America.
