AirshowThe Boeing Delta II Heavy engine approaches the top of the mobile service tower on Pad 17-B Cape Canaveral Air Force Station.

AirshowThe Boeing Delta II Heavy second-stage engine, the Aerojet AJ10-118K, approaches the top of the mobile service tower on Pad 17-B, Cape Canaveral Air Force Station. The engine will be mated with the first stage of the Delta II, which is the launch vehicle for the MESSENGER (Mercury Surface, Space Environment, Geochemistry and Ranging) spacecraft, scheduled to lift off Aug. 2. Bound for Mercury, the spacecraft is expected to reach orbit around the planet in March 2011. MESSENGER was built for NASA by the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.