After astronauts sent the first tweets and Twitpics from space, you had to know that checking in on Foursquare couldn't be far behind. That one small step for social networking in space took place today.

When the International Space Station's commander, NASA astronaut Doug Wheelock, clicked in his location, here's the momentous message he received in return: "You are now 220 miles above Earth traveling at 17,500 mph and unlocked the NASA Explorer Badge! Show this badge and get a free scoop of astronaut ice cream."

The Foursquare online application lets users "check in" at the places they visit, which can tell them which of their friends are nearby, what's interesting about the place they're at, and get little rewards like the virtual merit badge that Wheelock unlocked. (Foursquare also lets your friends know where you are, which can be a mixed blessing.)

There's not much question where Wheelock will be for the next month. His tour of duty on the space station is due to last until the end of November. So Foursquare probably won't be of much benefit to him until he's back on terra firma. But the social network's presence on the final frontier provides mutual coolness for the space agency and the online service.

"Check-ins from around the world have been cool, but this blew my mind!" Foursquare's CEO and co-founder, Dennis Crowley, said in today's NASA news release. "We're psyched to partner with NASA to help users explore the space program and the universe."

NASA is getting a customized Foursquare home page where the space agency will provide tips and information about the space program in locations throughout the United States. When Foursquare users check in to NASA sites -- ranging from the Cape in Florida to NASA HQ in Washington to NASA Ames and JPL in California -- they'll learn what's up at those locations. And if you're lusting after a NASA Explorer Badge, just sit tight. It'll be available for users to earn once Wheelock is back on Earth.