In-station fusion satellite

From Tardis Wiki, the free Doctor Who reference

In-station fusion satellites were a means of artificial lighting employed by the Company. In preparing to move the human population of Mars to Pluto, six of the satellites were placed in orbit around the new "branch". They required periodical refuelling and maintenance, creating high running costs.

When the resources of Pluto were depleted, the Company planned to abandon the planet. After several years, the satellites would cease to function and the humans would die. (TV: The Sun Makers)