Technicians monitor the progress as the AJ10 engine for the stage of a United Launch Alliance Delta II rocket is hoisted up in the service tower.

At Vandenberg Air Force Base in California, technicians monitor the progress as the AJ10 engine for the second stage of a United Launch Alliance Delta II rocket is hoisted up in the service tower at NASA’s Space Launch Complex-2. The Delta II 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