Salyut

But it ended after only two when the vehicle failed to dock with the Salyut 6 orbital space station.

The 18-ton rocket that fell last May was the heaviest debris to fall uncontrolled since the former Soviet space station Salyut 7 in 1991.

Since the Soviet Union launched the first space station, Salyut 1, 50 years ago, humans have lived on a total of 11 such facilities in Earth orbit.

For the moment, a new Russian space station—which would be a successor to the Salyut and Mir stations launched in the 1970s and ’80s—seems like a distant prospect.

Meanwhile, the Soviet Union built orbital outposts in the Salyut and Mir programs.