A quartet of ALMA antennas placed close together

The Atacama Large Millimeter/submillimeter Array (ALMA) antennas may look rooted to the ground in this striking image — taken at the Array Operations Site on the Chajnantor plateau, at an altitude of 5000 metres — but these dishes are surprisingly mobile.

Thanks to the two antenna transporter vehicles, the antennas in the array — which will consist of a total of 66 dishes when construction is complete — can be repositioned to meet the needs of a particular observation project. The transporters, named Otto and Lore, were specially designed to transport the hefty 115-tonne antennas and position them precisely on concrete foundation pads, spread across the plateau over distances of up to 16 kilometres. Here, four antennas have been placed on closely spaced pads for testing during the Commissioning and Science Verification phase of ALMA construction.

The transporter vehicles drive on 28 tyres, with two 700-HP (500 kW) diesel engines and two 1500-litre fuel tanks, and have a top speed of 12km/h when carrying their precious cargo.

The ALMA project is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ESO is the European partner in ALMA.