English: A 20-meter solar sail and boom system, developed by ATK Space Systems of Goleta, Calif., is fully deployed during testing at NASA Glenn Research Center's Plum Brook facility in Sandusky, Ohio. Blue lights positioned beneath the system help illuminate the four triangular sail quadrants as they lie outstretched in Plum Brook's Space Power Facility -- the world's largest space environment simulation chamber. The sail material is supported by a series of coilable booms, which are extended via remote control from a central stowage container about the size of a suitcase, and is made of an aluminized, plastic-membrane material called CP-1. The material is produced under license by SRS Technologies of Huntsville, Ala. The deployment, part of a series of tests in April, is a critical milestone in the development of solar sail propulsion technology that could lead to more ambitious inner Solar System robotic exploration.