Each volleyball-sized SPHERES has its own onboard power, propulsion, computing and navigational software. Adding the smartphone transforms the satellite into a free-flying robot, or "Smart SPHERES" -- complete with a compact, low-power, low-cost embedded computer and built-in cameras and sensors to enhance and expand robotic operations.
This close-up view shows three bowling-ball-sized free-flying satellites called Synchronized Position Hold, Engage, Reorient, Experimental Satellites (SPHERES) in the Destiny laboratory of the International Space Station. Image Credit: NASA.
MIT undergrads flight-test a prototype droid onboard NASA's KC-135 reduced gravity aircraft. Image Credit: NASA.
The MIT Space Systems Laboratory developed the SPHERES (Synchronized Position Hold Engage and Reorient Experimental Satellites) laboratory environment to provide DARPA, NASA, and other researchers with a long term, replenishable, and upgradable testbed for the validation of high risk metrology, control, and autonomy technologies for use in formation flight and autnomous docking, rendezvous and reconfiguration algorithms. These technologies are critical to the operation of distributed satellite and docking missions such as Terrestrial Planet Finder and Orbital Express.
To approximate the dynamics that will be encountered during these missions, the testbed consists of three small, self-contained vehicles, or "spheres," which can control their relative positions and orientations, and is operable on a 2-D laboratory platform, NASA's KC-135, and the International Space Station. SPHERES draws upon the MODE family of dynamics and control laboratories (STS-40, 42, 48, 62, MIR) by providing a cost-effective laboratory with direct astronaut interaction that exploits the micro-gravity conditions of space.
Here is a video of a recent Test Session aboard the ISS: