When you're the first to try something, you know that it comes with inherent risks.
If that something is flying people into outer space in an entirely new machine, those risks are rather high.
For a while, it seemed that Richard Branson's Virgin Galactic was a breezy, pioneering idea that was as much about entertainment, as about space.
Indeed, renowned Hollywood g-forces like Tom Hanks, Angelina Jolie, and Ashton Kutcher signed up very quickly.
Justin Bieber, too, thought it would be fun to get a little higher.
Wiser heads, though, like William Shatner demurred. Captain Kirk offered that he needed to be paid in order to undergo such an enterprising venture.
Now Branson himself has admitted that perhaps the biggest challenge facing the project is to ensure that no one dies.
He told the Guardian's Jon Ronson:
The biggest worry I had was re-entry. NASA has lost about 3% of everyone who's gone into space, and re-entry has been their biggest problem. For a government-owned company, you can just about get away with losing 3% of your clients. For a private company you can't really lose anybody.
It's a chillingly businesslike concept to declare that a 3 percent death rate is an acceptable margin of error for a government, but not for a private entity.
But it would, indeed, be something of a commercial killer if the inaugural flight (or those after it) incurred fatalities.
Branson, who insists that he and his children will be on the first flight, has put his faith in a design created by Burt Rutan.
The Virgin head described it like this: "Burt Rutan's idea was to turn a spaceship into a giant shuttlecock. And so the pilot could be sound asleep on re-entry and it didn't matter what angle it hit coming back into the Earth's atmosphere."
I'm not sure I'd be entirely comfortable about falling out of space with a sound-asleep pilot, but some are more confident of science's powers than others.
Virgin's SS2 hasn't yet managed to go the full 62 miles high, despite a promise to launch in the fall. And, as the Daily Mail reports, critics suggest that it still needs considerable redesigning before it will get the FAA's approval.
When your customers are paying $200,000 for a flight up there, your first priority must surely be at least bringing them back down here.