Cylethian

The Cylethian were an alien species from the planet Cylith.

The built a distress beacon into their space ships. Once it was used a inter-galactic rescue team would be on it's way to the place the signal was sent from. However when it would be pressed on Earth it would take them about 100 years to go there, because Cylith was very far away. (PROSE: The Day of the Clown)

Sarah Jane Smith had such a distress beacon in her attic at 13 Bannerman Road. (TV: The Day of the Clown)