NASA's Space Launch Complex 2 at Vandenberg Air Force Base is illuminated against a midnight blue sky.

NASA’s Space Launch Complex-2 at Vandenberg Air Force Base in California, is illuminated against a midnight blue sky as solid rocket motors are attached to the United Launch Alliance Delta II rocket that will carry NASA's National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite into space. NPP represents a critical first step in building the next-generation of Earth-observing satellites. NPP will carry the first of the new sensors developed for this satellite fleet, now known as the Joint Polar Satellite System (JPSS) to be launched in 2016. NPP is the bridge between NASA's Earth Observing System (EOS) satellites and the forthcoming series of JPSS satellites. The mission will test key technologies and instruments for the JPSS missions. NPP is targeted to launch Oct. 25. For more information, visit http://www.nasa.gov/NPP. Photo credit: NASA/VAFB, Mark Mackley