Space Station Alpha was the largest artificial satellite in orbit around planet Earth about 3769. It was many years in construction and had an army of engineers, construction workers and robots (employing many Technomatics).
Some five years into its construction, the Klytode attempted to blow it up with a cobalt bomb, sending the space station crashing into the Earth, catastrophically changing its climate. The plan was thwarted by the Tenth Doctor who ejected the bomb into space.
Incidently, snag finders (low-level construction inspectors) Jimmy and Welding Bot X-5 'Bert' successfully went on to live the career of their dreams following the Klytode's capture and arrest. (COMIC: The Snag Finders)