Three bowling ball-size free-flying Synchronized Position Hold, Engage, Reorient, Experimental Satellites (SPHERES) have been flying inside the International Space Station since 2006. These satellites provide a test bed for development and research, each having its own power, propulsion, computer, navigation equipment, and physical and electrical connections for hardware and sensors for various experiments.

Aboard Orbital Sciences Corp.'s second contracted commercial resupply mission to the space station, which arrived to the orbital laboratory on July 16, NASA's Ames Research Center in Moffett Field, California, sent two Google prototype Project Tango smartphones that astronauts will attach to the SPHERES for technology demonstrations inside the space station.

By connecting a smartphone to the SPHERES, the technology becomes "Smart SPHERES, " a more "intelligent" free-flying robot with built-in cameras to take pictures and video, sensors to help conduct inspections, powerful computing units to make calculations and Wi-Fi connections to transfer data in real time to the computers aboard the space station and at mission control in Houston.

In a two-phase experiment, astronauts will manually use the smartphones to collect visual data using the integrated custom 3-D sensor to generate a full 3-D model of their environment. After the map and its coordinate system are developed, a second activity will involve the smartphones attached to the SPHERES, becoming the free-flying Smart SPHERES. As the free-flying robots move around the space station from waypoint to waypoint, utilizing the 3-D map, they will provide situational awareness to crewmembers inside the station and flight controllers in mission control. These experiments allow NASA to test vision-based navigation in a very small mobile product.

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