Nasa will let tourists visit the International Space Station (ISS) from 2020.
The US space agency said it would open the space station to tourism and other business opportunities.
There will be up to two short private astronaut missions a year, with the stay on board costing $35,000 (£27,500) a night.
Nasa said that private astronauts would be allowed to travel to the ISS for up to 30 days, travelling on US spacecraft.
American companies Boeing and SpaceX are already developing capsules to carry humans to the ISS, and Nasa said the two companies would handle private tourists and any services related to them.
The two companies could charge a private astronaut close to $60 million (£47 million) per flight to space.
The commercial company looking after the private astronaut missions would also have to make sure the tourists meet Nasa's strict medical standards and training for spaceflight.
Nasa, which is funded by the American taxpaying public, pays for the US operation of the ISS.
It had previously banned any commercial use of the space station.
But now Nasa has been looking for new ways of funding to help pay for its activities.
"We're here because the International Space Station is now open for business," Nasa lead spokesperson Stephanie Schierholz said at a conference in New York, USA.
Their plan to raise money includes allowing private business activities to take place on the ISS, including in-space manufacturing, marketing activities, healthcare research and more.
Nasa's goal overall is to become "one of many" users of the ISS and low-Earth orbit facilities.