Japanese space agency (Jaxa) scientists want to detect a measurable acceleration in the spacecraft as photons - the particles of light - from the Sun fall on the roughly 200-sq-m, ultra-thin sheet.

BBC: Mini-camera pictures Japan's Ikaros solar sail

This shield does not stop all the cosmic rays from getting though, and its effectiveness varies with the long-term changes in the activity of the Sun, which can rise and fall on a timescale of centuries.

BBC: Viewpoint: The Sun and climate change

Careful positioning of the sail should slow the probe down, causing it to fall towards the sun.

ECONOMIST: Rockets are not the only way to travel through outer space

In the fall of 1998, Whyte issued an injunction ordering Microsoft to make its products compatible with Sun's Java specifications.

CNN: Judge reinstates piece of Java injunction against Microsoft