British physicist Stephen Hawking has completed a zero-gravity flight in a specially modified plane provided by Zero Gravity Corporation.

Hawking, who suffers from motor neuron disease, was able to float free, unrestricted by his paralysed muscles and his wheelchair.

He believes private space ventures are vital to reduce the cost of space tourism and make it accessible to a greater number of people.

“I think the human race doesn’t have a future if it doesn’t go into space,” he said.