STS-41-D was the first flight of NASA's Space Shuttle orbiter Discovery. It was the 12th mission of the Space Shuttle program, and was launched from Kennedy Space Center, Florida, on 30 August 1984. Three commercial communications satellites were deployed into orbit during the six-day mission, and a number of scientific experiments were conducted.

The mission was delayed by more than two months from its original planned launch date, having experienced the Space Shuttle program's first launch abort at T-6 seconds on 26 June 1984.

The launch was originally planned for 25 June 1984, but because of a variety of technical problems, including rollback to the Vehicle Assembly Building to replace a faulty main engine, the launch was delayed by over two months. STS-41-D finally launched on 8:41 am EDT on 30 August, after a six-minute, 50-second delay when a private aircraft flew into the restricted airspace near the launch pad. It was the fourth launch attempt for Discovery. The June launch attempt marked the first time since Gemini 6A that a manned spacecraft had experienced a shutdown of its engines just prior to launch.