Best known for his role as Captain Kirk, the 90-year-old Shatner has joined three other passengers for the planned launch from West Texas.

Bezos' space travel company, Blue Origin, invited Shatner on the brief jaunt to the fringes of the final frontier, which will make him the oldest person in space.

It will be Blue Origin's second passenger flight, using the same capsule and rocket that Bezos used for his own launch three months ago.

The trip should last just 10 minutes, with the fully automated capsule reacing a maximum altitude of about 106km before parachuting back into the desert.

Virgin Galactic's Richard Branson kicked off the US-based space tourism boom on July 11, riding his own rocketship to space.

Bezos followed nine days later aboard his own capsule. Elon Musk stayed behind as his SpaceX company launched its first private flight last month, sending a billionaire, cancer survivor and two ticket winners into orbit.

And last week, the Russians sent an actor and film director to the International Space Station for movie-making.

"We're just at the beginning, but how miraculous that beginning is. How extraordinary it is to be part of that beginning," Shatner said in a Blue Origin video posted on the eve of his flight.

"It looks like there's a great deal of curiosity about this fictional character, Captain Kirk, going into space. So let's go along with it and enjoy the ride."

Rounding out the crew: a Blue Origin vice president and two entrepreneurs who bid unsuccessfully for a seat on the previous flight with Bezos, the founder of Amazon. Blue Origin did not divulge their ticket prices.

Bezos was at the expansive launch and landing site near Van Horn, Texas, to see the four off.

Australian Associated Press