Great Solar Shield
The Great Solar Shield was a space station built in the 21st century.
It was designed by humans to orbit and protect Earth, and consisted of a network of prismatic mirrors to block sunlight from the planet, creating a partial eclipse for the planet which would reduce the rate of global warming. The crew of the Great Solar Shield were not to return to Earth.
The space station once came under attack by the Silhouettes, who were searching for energy to feed on. They descended on Earth after being frightened off by the colour in Martha Jones' shirt, but the Tenth Doctor aligned the prismatic mirrors with the sunlight, splitting it into different wavelengths and creating a rainbow that scared the Silhouettes away. The space station disintegrated as a result, but the Doctor told Martha that the human race would eventually find another solution to its global warming problems. (COMIC: Sunscreen)