NASA's Stratospheric Observatory for Infrared Astronomy, or SOFIA, arrived at NASA's Dryden Flight Research Center at Edwards Air Force Base, Calif. on May 31, 2007. The heavily modified Boeing 747SP was ferried to Dryden from Waco, Texas, where L-3 Communications Integrated Systems installed a German-built 2.5-meter infrared telescope and made other major modifications over the past several years. SOFIA is scheduled to undergo installation and integration of mission systems and a multi-phase flight test program at Dryden over the next three years that is expected to lead to a full operational capability to conduct astronomy missions in about 2010. During its expected 20-year lifetime, SOFIA will be capable of "Great Observatory" class astronomical science, providing astronomers with access to the visible, infrared and sub-millimeter spectrum with optimized performance in the mid-infrared to sub-millimeter range.