MONTREAL - Even though more than a dozen Canadians have already signed up for commercial space flights, the country's most famous astronaut has no intention of joining them.

That's because the man who rose to fame playing Capt. James T. Kirk is, as it turns out, not crazy about the idea of visiting space.

William Shatner, the Star Trek protagonist, explained Thursday why he has no intention to boldly go anywhere beyond the Earth's atmosphere.

"I'm scared," the 80-year-old told a news conference, after he was given an honorary doctorate of Letters at his alma mater, Montreal's McGill University.

Shatner publicly expressed reticence years ago when asked whether he might ever take advantage of new opportunities in space travel. He went further Thursday, explaining at a news conference why it won't happen.

Virgin Galactic, one of billionaire Richard Branson's many companies, has already booked more than 300 suborbital flights.

The company hopes to complete its test phase and begin launching flights next year. Its plan for suborbital flights mean its ships would go up into space, without completing an orbit of the Earth.

Fourteen of those signed up to fly are Canadians.

Shatner says Branson offered him a spot -- which would have cost US$200,000.

"I said, 'Well, that's not much, (but) how much do you guarantee to come back?' And he didn't have a price on that," Shatner quipped.

"He (Branson) wanted me to go up and pay for it and I said: 'Hey, you pay me and I'll go up. I'll risk my life for a large sum of money.' ... But he didn't pick me up on my offer."

It was widely reported in September 2006 that the Star Trek legend was offered a ticket by Branson aboard Virgin Galactic's first passenger flight -- which was originally planned for 2008.

At the time, Shatner said he was worried about getting sick.

"I'm interested in man's march into the unknown but to vomit in space is not my idea of a good time. Neither is a fiery crash with the vomit hovering over me," he said at the time.