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 August 8, 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 August 13, 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).