The first of the James Webb space telescope’s (JWST) beryllium primary mirror segments has been cryo-polished to its required level, as measured at operational cryogenic temperatures.

The JWST’s 6.5m beryllium primary mirror will make infrared observations of the history of the universe and the evolution of our solar system.

Each of the 18 hexagonal-shaped mirror assemblies of the primary mirror measures over 1.3m across and weighs approximately 40kg after lightweighting.

Cryogenic polishing ensures that when the mirror reaches its extremely cold operating temperature, its shape conforms to requirements for collecting accurate infrared images of distant stars and galaxies.

The first mirror tested is an engineering development unit mirror that will be used as a flight spare.

The space telescope, a joint project of Nasa, the European Space Agency and the Canadian Space Agency, is scheduled for launch in 2014.

James Webb (1906-1992) was Nasa administrator between 1961 and 1969, and was instrumental in sending manned missions into space and to the moon, working with both President Kennedy and Johnson.