ALMA (Atacama Large Millimeter/submillimeter Array) is under construction in Chile in global partnership between East Asia, Europe, and North America. On December 9, the first antenna transport test was conducted with one of the 12-m antennas manufactured by Japan and a transporter manufactured by Europe, and the antenna was successfully transferred by the transporter within the Operations Support Facility (OSF).

The transporter carrying the antenna started from the NAOJ area at OSF, made a sharp turn before the gate, and ascended the slope with inclination up to 10%. The maximum velocity was 5 kilometers per hour.
The transporter has a gigantic body: 10 meters wide and 18 meters long; however it turns beautifully in a small radius with 28 wheels (14 pairs) which are individually driven. These individually-driven 14 pairs of wheels make the transporter enable to move and stop precisely at a specified position even in the antenna pad area with many restrictions.

The ACA 12-m antenna is an ultra-precision instrument weighing about 100 tons. In order to move the antenna without having impact on its performance, close attention is required to avoid excessive pressure to the antenna in any phase of transport.
Throughout the test, inspections and measurements were conducted very carefully in all the steps: connection between the antenna and transporter, lift of the antenna, movement on flat surfaces and sloping roads, and setting of the antenna.

Another sensitive and more important matter is safety. As this is an operation involving massive equipment where a 100-ton antenna is carried by a 150-ton transporter, it is required to take thorough safety measures mechanically and electrically. One of the major objectives of this test was to check the operation procedures based on such safety design.

For the international project ALMA, it is especially gratifying that the antenna was successfully transported by connecting two precision instruments, which were manufactured separately in Japan and Europe, safely and securely both for the personnel and the machine.

You can see the moving images of the antenna carried by the transporter.
Movie [Click here] (QuickTime : 56.6 MB)。