Blue Origin is launching the TV star William Shatner on Tuesday, but employees say they wouldn't fly on that rocket

• Blue Origin plans to fly "Star Trek" actor William Shatner and others to the edge of space Tuesday.
• In a recent open letter, some Blue Origin employees said they wouldn't ride its New Shepard rocket.
• New Shepard's emergency systems should protect passengers, but the letter raised safety concerns.

After launching its own founder, Jeff Bezos, to the edge of space this summer, the rocket company Blue Origin has moved on to its first celebrity customer.

William Shatner, the actor best known for playing Captain James T. Kirk in "Star Trek," is set to fly 62 miles above sea level aboard the company's New Shepard launch system on Tuesday. He'll share the spaceship with the former NASA engineer Chris Boshuizen, the healthcare entrepreneur Glen de Vries, and Blue Origin's vice president of mission and flight operations, Audrey Powers. The flight is automated, so no pilot will be on board.

At the peak of their 11-minute flight, the passengers will briefly experience weightlessness. They'll be able to see the curvature of the Earth and its thin atmosphere against the blackness of space.

Shatner, who is 90, will be the oldest person to reach the boundary of space, breaking the record set by 82-year-old aviator Wally Funk on Blue Origin's first passenger flight with Bezos.

"I'm thrilled and anxious and a little nervous and a little frightened about this whole new adventure," Shatner told the "Today" show on Tuesday.

But the flight comes amid fallout from a recent open letter from current and former Blue Origin employees. It called New Shepard's safety into question, with some of the anonymous employees who signed it saying they would not fly on the rocket themselves.

Spaceflight has always been risky, but the private companies now rocketing people to space face little government oversight. Passengers like Shatner fly at their own risk.

Employees said 'making progress for Jeff' trumps safety

New Shepard has flown 16 times without any apparent errors - a strong record. But some Blue Origin employees said in the letter that things look more concerning from the inside.

Alexandra Abrams, who used to head Blue Origin's employee communications, published the letter on the website Lioness last week. Abrams was the only named author, but she said 20 other current and former Blue Origin employees cowrote it. CBS News spoke with five of them, and two confirmed that they would not feel comfortable riding a Blue Origin spacecraft.

"Competing with other billionaires - and 'making progress for Jeff' - seemed to take precedence over safety concerns that would have slowed down the schedule," the letter said.

It continued: "Some of us felt that with the resources and staff available, leadership's race to launch at such a breakneck speed was seriously compromising flight safety."

The letter added that for many of the coauthors, safety was "the driving force" behind the decision to publish it.

"In the opinion of an engineer who has signed on to this essay, 'Blue Origin has been lucky that nothing has happened so far,'" the letter said. "Many of this essay's authors say they would not fly on a Blue Origin vehicle."

In a statement emailed to Insider, Blue Origin said, "We stand by our safety record and believe that New Shepard is the safest space vehicle ever designed or built."

The statement added that Abrams "was dismissed for cause two years ago after repeated warnings for issues involving federal export control regulations." Abrams has denied receiving such warnings.

New Shepard has safety features in case of emergency

The most nail-biting moments of a spaceflight are when the engines burn for liftoff, when the rocket separates from the capsule, and when parachutes deploy on the way down.

Blue Origin has not shared much detail about its testing process, but it has highlighted some of New Shepard's safety features.

Once the New Shepard rocket lifts off, it screams through the atmosphere for about three minutes before releasing the passenger capsule and falling back to Earth. During that time, if something goes wrong, an emergency-escape system should prompt the capsule to detach and jettison away from impending doom.

Blue Origin has tested that escape system three times - on the launchpad, in midair, and in space. Presumably, this means that if the rocket threatens to explode, the capsule should be able to carry its passengers to safety.

Then once the capsule is falling back to Earth, three parachutes should deploy. If one fails, the capsule is designed to give more thrust to its downward-facing engines. If two parachutes fail, a crushable "bumper" section on the bottom of the capsule should absorb the impact of landing.

"The capsule is the most highly redundant and safe spaceflight system, we think, that has ever been designed or flown," Gary Lai, senior director of New Shepard's design, says in a Blue Origin video about safety. "In most cases, you have a backup to the backup system."

The capsule also has oxygen masks, much like on an airplane, in case the cabin becomes depressurized.

Blue Origin passengers fly at their own risk

About 1% of US human spaceflights have resulted in a fatal accident, according to an analysis published earlier this year.

"That's pretty high. It's about 10,000 times more dangerous than flying on a commercial airliner," George Nield, a coauthor of that report, previously told Insider. Nield formerly served as the Federal Aviation Administration's associate administrator and led its Office of Commercial Space Transportation.

No federal agency regulates the safety of passengers on private commercial spaceflights. For now, the FAA just ensures that these rocket launches don't pose a threat to other aircraft or to people on the ground. However, in a statement emailed to Insider last week, the FAA said it was "reviewing" the open letter from Blue Origin employees.