The 90-year-old, who played Captain James T Kirk in the Star Trek films and TV series, has become the oldest person to go to space today. He blasted off from the Texas desert at about 3.50pm BST with three other individuals. The Canadian flew on board Blue Origin's New Shephard rocket, developed by Amazon.com founder Jeff Bezos.

       The Star Trek veteran returned to Earth at about 4pm BST, after spending just a few minutes in weightlessness.

       Blue Origin tweeted: "Capsule touchdown! Welcome home to the crew of #NS18!"

       Before his flight, Mr Shatner said: "I'm thrilled and anxious and a little nervous and a little frightened about this whole new adventure,"

       "But I've got to think that once it's done, once I've been into space and seen the universe and seen our Earth and the contrast between that hostility and this warmth, and how important it is to keep the Earth alive so that we don't wreck it, we human beings don't wreck it, that contrast in all of that is so dramatic to me."

       It has left some concerned for him.

       Following the flight Shatner said he was shocked by the difference in the blue sky of Earth and the vast blackness of space, adding: "It was so moving to me. This experience has been unbelievable."

       He appeared stunned in his conversation with Mr Bezos, admitting he was taken aback by how quickly he reached space. "In a way it's indescribable," he said.

       Shatner added it was "the most profound experience I can imagine".

       He said: "I am so filled with emotion about what just happened, it's extraordinary. Extraordinary. I hope I never recover from this. I hope I can maintain what I feel now. I don't want to lose it. It's so much larger than me."

       Further trying to explain the experience to Mr Bezos, Shatner said: "It has to do with the enormity and the quickness and the suddenness of life and death."

       Twitter user @OfSelina said: "Hope William Shatner is all safe going up into space today. He's 90.

       "My Dad is 70 and I get worried when he starts walking up tube station escalators."

       Another user, @hobohumpinslobo, added: "I’m legitimately worried about William Shatner going into space."

       A third asked: "Is anybody else worried about William Shatner going to space?

       And @dvvd11789881 simply said: "I’m worried about William Shatner.

       Mr Shatner was blasted 66 miles up above the Earth's surface to experience a few minutes of weightlessness, before parachuting back to the desert floor.

       But medical expert Dr Mark Porter has quashed any fears, writing in The Times that his "good genes will help" him handle the g-force.

       He added: "None of us can hold back the ravages of time, but if you manage to hit 90 then you are likely to be better at it than most thanks to good genes and clean living. And assuming you can pass a thorough medical — and Shatner will have had one — then a brief flight into weightlessness is unlikely to pose much threat.

       "The combination of high g-forces and excitement (or fear) will put an extra load on his heart and brain but Nasa studies suggest that older people often handle high g-force better than their younger peers.

       "Most of the other health hazards of space travel, like bone and muscle loss, radiation exposure and changes in visual acuity, only become relevant after long periods, so Shatner need not worry about these.

       "However, vertigo and space sickness may be more of an issue for him due to age-related changes in his balance mechanism, but I am sure he can handle this given the brevity of his trip."

       This will be only the second crewed outing for New Shepard. The first, on July 20, carried Mr Bezos, his brother Mark, Dutch teenager Oliver Daemen; and famed aviator Wally Funk.

       Afterwards, Ms Funk, being 82, was able to claim the record for the oldest person in space – a title she will now relinquish to Mr Shatner.