Space Shuttle program: STS-28 Mission: Space Shuttle Columbia takes off on a secret five-day military mission.

STS-28 was the 30th NASA Space Shuttle mission, the fourth shuttle mission dedicated to United States Department of Defense (DoD) purposes, and the eighth flight of Space Shuttle Columbia. The mission launched on 8 August 1989 and traveled 3,400,000 km (2,100,000 mi) during 81 orbits of the Earth, before landing on runway 17 of Edwards Air Force Base, California, on 13 August 1989. STS-28 was also Columbia's first flight since January 1986, when it had flown STS-61-C, the mission directly preceding the Challenger disaster of STS-51-L. The mission details of STS-28 are classified, but the payload is widely believed to have been the first SDS-2 relay communications satellite. The altitude of the mission was between 295 km (183 mi) and 307 km (191 mi).The mission was officially designated STS-28R as the original STS-28 designator belonged to STS-51-J, the 21st Space Shuttle mission. Official documentation for that mission contained the designator STS-28 throughout. As STS-51-L was designated STS-33, future flights with the STS-26 through STS-33 designators would require the R in their documentation to avoid conflicts in tracking data from one mission to another.

The Space Shuttle program was the fourth human spaceflight program carried out by the U.S. National Aeronautics and Space Administration (NASA), which accomplished routine transportation for Earth-to-orbit crew and cargo from 1981 to 2011. Its official name, Space Transportation System (STS), was taken from a 1969 plan for a system of reusable spacecraft of which it was the only item funded for development.The Space Shuttle—composed of an orbiter launched with two reusable solid rocket boosters and a disposable external fuel tank—carried up to eight astronauts and up to 50,000 lb (23,000 kg) of payload into low Earth orbit (LEO). When its mission was complete, the orbiter would reenter the Earth's atmosphere and land like a glider at either the Kennedy Space Center or Edwards Air Force Base.

The Shuttle is the only winged crewed spacecraft to have achieved orbit and landing, and the first reusable crewed space vehicle that has made multiple flights into orbit. Its missions involved carrying large payloads to various orbits including the International Space Station (ISS), providing crew rotation for the space station, and performing service missions on the Hubble Space Telescope. The orbiter also recovered satellites and other payloads (e.g., from the ISS) from orbit and returned them to Earth, though its use in this capacity was rare. Each vehicle was designed with a projected lifespan of 100 launches, or 10 years' operational life. Original selling points on the shuttles were over 150 launches over a 15-year operational span with a 'launch per month' expected at the peak of the program, but extensive delays in the development of the International Space Station never created such a peak demand for frequent flights.