Launch Complex 39B (LC-39B) is the second of Launch Complex 39's three launch pads, located at NASA's Kennedy Space Center in Merritt Island, Florida. The pad, along with Launch Complex 39A, was first designed for the Saturn V launch vehicle, which at the time was the United States' most powerful rocket. Typically used to launch NASA's crewed spaceflight missions since the late 1960s, the pad is currently configured for use by the agency's Space Launch System rocket, a Shuttle-derived launch vehicle which is currently used in the Artemis program and subsequent Moon to Mars campaigns. The pad had also been leased by NASA to aerospace company Northrop Grumman, for use as a launch site for their Shuttle-derived OmegA launch vehicle, for National Security Space Launch flights and commercial launches, before the OmegA program was cancelled.

Launch Complex 39 (LC-39) is a rocket launch site at the John F. Kennedy Space Center on Merritt Island in Florida, United States. The site and its collection of facilities were originally built as the Apollo program's "Moonport" and later modified for the Space Shuttle program.