The mobile service tower moves around the Boeing Delta II rocket for installation of the remaining solid rocket boosters.

On Launch Pad 17-B at Cape Canaveral Air Force Station in Florida, the mobile service tower moves around the Boeing Delta II rocket for installation of the remaining solid rocket boosters. The Delta rocket is the launch vehicle for NASA's Solar Terrestrial Relations Observatory (STEREO). Preparations are under way for a liftoff no earlier than Aug. 1. STEREO consists of two spacecraft whose mission is the first to take measurements of the sun and solar wind in 3-D. This new view will improve our understanding of space weather and its impact on the Earth. Photo credit: NASA/Kim Shiflett