The signs on the side of this launch tower on Pad 17-B, Cape Canaveral Air Force Station, show the type of vehicle and payload to be launched from there. The Delta II is the launch vehicle for the MESSENGER spacecraft, scheduled to lift off Aug. 2, bound for Mercury. The spacecraft is expected to reach orbit around Mercury in March 2011. MESSENGER was built for NASA by the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.