The robots, known as Spheres (Synchronised Position Hold, Engage, Reorient, Experimental satellites), currently have limited capabilities.
It is hoped the smartphones, powered by Google's Project Tango, will equip the robots with more functionality.
The robots have been described by experts as "incredibly clever".
When Nasa's robots first arrived at the International Space Station in 2006, they were only capable of precise movements using small jets of CO2, which propelled the devices forwards at around an inch per second.
"We wanted to add communication, a camera, increase the processing capability, accelerometers and other sensors," Spheres project manager Chris Provencher told Reuters.
he Kentucky State Police received multiple reports of sightings. A couple of days later, the Appalachian News-Express ran a story headlined "Mystery Object in Sky Captivates Locals." Regional television stations reported that government agencies professed ignorance. The story was picked up by CNN. And the UFO-loving website Ashtar Command Crew linked to the news as ostensible proof of continuing visits from the Galactic Federation fleet. Epling, for his part, didn't jump to extraterrestrial conclusions. But still, what was it?
Rich DeVaul knows. Sitting in a conference room in Mountain View, California, he beams proudly as he runs a YouTube clip of one of the newscasts. The mysterious craft was his doing. Or, at least, the work of his Google team. The people in Pike County were witnessing a test of Project Loon, a breathtakingly ambitious plan to bring the Internet to a huge swath of as-yet-unconnected humanity—via thousands of solar-powered, high-pressure balloons floating some 60,000 feet above Earth.