A close-up view of a bowling-ball-sized free-flying satellite known as Synchronized Position Hold, Engage, Reorient, Experimental Satellites, or SPHERES is pictured during a session in the International Space Station's Kibo laboratory. NASA astronaut Chris Cassidy, Expedition 36 flight engineer, is visible in the background.
NASA
<a rel="nofollow" class="external free" href="http://spaceflight.nasa.gov/gallery/images/station/crew-36/html/iss036e031693.html">http://spaceflight.nasa.gov/gallery/images/station/crew-36/html/iss036e031693.html</a>