NOAA-18 was launched by the Delta II launch vehicle on 20 May 2005 at 10:22:01 UTC from Vandenberg Air Force Base, at Vandenberg Space Launch Complex 4 (SLW-4W), in a Sun-synchronous orbit, at 854 km above the Earth, orbiting every 102.12 minutes. NOAA-18 is in an afternoon equator-crossing orbit and has replaced the NOAA-17 as the prime afternoon spacecraft.
