Three Google-HTC Nexus One smartphones, encased in 4-inch metal cubes and dubbed PhoneSats, are circling Earth at an altitude of about 150 miles, the space agency said.
Running the Android operating system, the PhoneSats' mission is to take photos of Earth and send back periodic radio messages, to gauge what smartphones are capable of and if they could be the "brains" of future satellites, NASA officials said.
They were launched Sunday atop an Orbital Science Corp.'s Antares rocket from Wallops Island Flight Facility in Virginia, the Los Angeles Times reported.
Amateur radio operators have been notifying NASA they are picking up radio signals from the satellites, NASA spokeswoman Ruth Marlaire said.
The mission will be a short one, with the PhoneSats burning up on re-entry into the Earth's atmosphere within the next two weeks, NASA said.