A successful test-firing was held on Friday and the first nuclear collisions will take place in the autumn, building up to full power around the time of the millennium.

Google Chrome OS is being created for people who spend most of their time on the web, and is being designed to power computers ranging from small netbooks to full-size desktop systems.

The next stages of construction were to expand the station's power and life-support systems to support a full-time crew of six or seven.