The last of five space walks finally fixes the problems with the Hubble telescope.

The Hubble telescope had a design flaw - the main mirror was said to be flatter than it should have been. It was only out by 1/50th of the width of a human hair, but the result was it was only as good as an earth based telescope which was a major embarrassment for NASA who had spent $1.55bn on the project.

The main flaw was rectified, apparently, by placing on it a sort of contact lens which corrected the defect. The astronauts also fixed around 10 other defects.

Due to the rotation of the planet, the astronauts (Story Musgrave and Jeff Hofman) traveled at 17,000 miles an hour while correcting the telescope. They were 360 miles above the Earth's surface.