ALMA antennas are assembled at the OSF (Operations Support Facility) at 2900 meters, and completed antennas are transported by a dedicated transporter to the AOS (Array Operations Site) at 5000 meters. The ALMA project adopts this policy to prevent possible high-altitude diseases and impairment of concentration at 5000-meter altitude.

According to this policy, Japanese three antennas will be assembled at the OSF. From the day after the arrival, the installation of three antennas started: the first antenna was installed on the first day and remaining two antennas on the second day. They were safely placed on the antenna foundations using a 300-ton crane. We anticipated that it would be very difficult to install heavy antenna mounts weighing about 80 tons each at a specified position, but the installation work was conducted rather smoothly in collaboration between Japanese and Chilean workers.

After work, Director of the Joint ALMA Office (JAO), Massimo Tarenghi visited the construction site to celebrate the successful transport and installation of the three antennas at the OSF. Currently, assembly of main reflectors is underway as you can see in the photo.