New York (CNN Business) A space revolution is upon us — so says the new wave of tech entrepreneurs pledging to colonize the cosmos.

Several billionaires and their hard-charging rocket companies say the tiny roster of humans — 573, by the count of space expert Jonathan McDowell — who have flown to space is about to get much longer. They promise that more Average Joes can have experiences long relegated to highly trained astronauts.

But the galactically curious should take heed: Space travel will probably remain prohibitively expensive for anyone outside the 1% for a long, long time.

A stay on the International Space Station costs tens of millions of dollars. A group called Space Adventures has offered wealthy individuals the opportunity to fly to the station aboard Russian-built rockets, and so far seven clients have made the trek. Most recently, Cirque Du Soleil billionaire Guy Laliberte paid $35 million to spend a couple weeks in space. And after NASA announced earlier this year it would open the US portion of the ISS to private astronauts, Bigelow Aerospace said it would coordinate rides for $52 million a seat.

SpaceX is also planning to charge an undisclosed amount of money to a Japanese billionaire for a moon mission slated for next decade.

Read More