SPHERES miniature satellites. Researchers holding miniature satellites known as Synchronised Position Hold Engage Re-orient Experimental Satellites (SPHERES). They are designed to orbit in formation within the space shuttle or International Space Station. A network of smaller satellites is thought to be cheaper and more flexible than using conventional satellites which are much larger and more expensive. The SPHERES satellites communicate with each other and to a central computer with wireless signals. Small propellant tanks allow positional adjustments to be made in microgravity without human intervention. Photographed in 2005 at the Massachusetts Institute of Technology (MIT), USA.