WASHINGTON — A NASA astronaut on Friday used the popular location-sharing service Foursquare to "check in" from space.

Douglas Wheelock, who is orbiting the Earth aboard the International Space Station, sent a message from his Twitter account, @Astro_Wheels, saying he had "unlocked the 'NASA Explorer Badge'" on Foursquare.

Foursquare, which boasts more than four million members, allows users to broadcast their whereabouts to other users of the service and earn "badges" for the places they check in from or to become the "mayor."

The NASA Explorer Badge can be earned by those who are "220 miles above the Earth traveling at 17,500 mph," which puts Wheelock in a rarified category.

"Check-ins from around the world have been cool, but this blew my mind!" Foursquare co-founder and chief executive Dennis Crowley said.

"We're psyched to partner with NASA to help users explore the space program and the universe," Crowley said.

NASA has been quick to adopt Facebook, Twitter and other social networking tools and offers Foursquare badges to visitors to a number of NASA facilities, including the Kennedy Space Center in Florida and mission control in Houston.

Timothy Creamer, a NASA flight engineer, sent the first "tweet" from space in January and astronauts have been tweeting regularly since then.

Japanese astronaut Soichi Noguchi earlier this year used Twitpic to send spectacular pictures of Earth as seen from space, including views of Mount Kilimanjaro, Mount Fuji and other landmarks.

NASA's Foursquare page is located at foursquare.com/NASA