Assembly of a European ALMA antenna

A European antenna for ALMA, the Atacama Large Millimeter/submillimeter Array, is placed on its base. The 12-metre diameter reflecting dish is attached to the base, with the whole structure weighing over 100 tonnes. When complete, the reflecting surface of the dish will be accurate to less than the thickness of a sheet of paper, and the antenna will be able to point precisely enough to pick out a golf ball at a distance of 15 kilometres. This is the second European antenna to be assembled at the 2,900-metre altitude Operations Support Facility in Chile. The antennas will ultimately be transported to the Chajnantor plateau, 5000 metres above sea level in the Chilean Andes.

ALMA, which will comprise 66 giant 12-metre and 7-metre diameter antennas observing the Universe at millimetre and submillimetre wavelengths, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ESO has contracted with the AEM (Alcatel Alenia Space France, Alcatel Alenia Space Italy, European Industrial Engineering S.r.L., MT Aerospace) Consortium for the supply of 25 of the 12-metre diameter ALMA antennas.