STS-27 was a crucial mission for NASA and the United States Department of Defense, marking Atlantis' second flight in a pivotal role for military satellite deployment during a period of heightened geopolitical tension and strategic national defense priorities. Launched from NASA's Kennedy Space Center in Florida, the purpose of this mission was to place a classified payload into low Earth orbit, part of a series of missions focused on military reconnaissance and technological development. Atlantis lifted off successfully, despite being marked by concerns over the shuttle's reliability following earlier missions, notably the Challenger disaster in 1986.

The flight lasted approximately five days and included various experiments, though the exact nature of the primary payload remained classified at the time. During the mission, Atlantis also demonstrated the capabilities of the Global Positioning System (GPS) technology, ensuring that navigating and tracking satellites became more efficient and accurate. The mission was notable not only for its military implications but also for the strides made in shuttle technology, such as improvements in thermal protection systems and the general operation of the orbiter itself, paving the way for future missions.

After completing its mission objectives, Atlantis safely returned to Earth on December 6, 1988. The entire operation highlighted NASA's commitment to dual-use technology, benefiting both civilian and military applications. The secrecy surrounding the mission showcased the delicate balance between technological advancement and national security, a recurring theme in the late Cold War period, reflecting the broader context in which this mission was executed.