Editing Atacama Large Millimeter Array (section)

=== Transporting the antennae ===
[[File:Alma antenna in transit.jpg|thumb|Alma antenna in transit on board of the transporter.]]

Transporting the 115&nbsp;[[tonne]] antennae from the Operations Support Facility at 2900&nbsp;m altitude to the site at 5000&nbsp;m, or moving antennae around the site to change the array size, presents enormous challenges; as portrayed in the television documentary ''Monster Moves: Mountain Mission''.<ref>{{Cite web |url=http://www.windfallfilms.com/show/1759/Monster-Moves-Episode-6-Mountain-Mission.aspx |title=Monster Moves, Season 5, Episode 6: Mountain Mission |access-date=17 March 2012}}</ref> The solution chosen is to use two custom 28-wheel self-loading [[heavy hauler]]s. The vehicles were made by {{Interlanguage link multi|Scheuerle Fahrzeugfabrik|de}}<ref>[http://www.scheuerle.de/en/products/new-vehicles/special-transporters/antenna-transporter.html Scheuerle Fahrzeugfabrik]</ref> in Germany and are 10&nbsp;m wide, 20&nbsp;m long and 6&nbsp;m high, weighing 130&nbsp;tonnes. They are powered by twin [[Turbocharger|turbocharged]] 500&nbsp;kW [[diesel engine]]s.

The transporters, which feature a driver's seat designed to accommodate an [[oxygen]] tank to aid breathing the thin high-altitude air, place the antennae precisely on the pads. The first vehicle was completed and tested in July 2007.<ref>{{Cite news |url=http://news.bbc.co.uk/2/hi/science/nature/6922967.stm |title=Giant truck set for sky-high task |work=BBC News |date=30 July 2007 |access-date=31 July 2007}}</ref> Both transporters were delivered to the ALMA Operations Support Facility (OSF) in Chile on 15 February 2008.

On 7 July 2008, an ALMA transporter moved an antenna for the first time, from inside the antenna assembly building (Site Erection Facility) to a pad outside the building for testing (holographic surface measurements).<ref>July 2008 NRAO ALMA newsletter article by Dr. Al Wootten</ref>

[[File:ALMA transporter known as Otto.jpg|left|thumb|ALMA transporter known as Otto.<ref>{{cite web|title=Beauty and a Beast|url=https://www.eso.org/public/images/potw1703a/|website=www.eso.org|access-date=23 January 2017}}</ref>]]

During Autumn 2009, the first three antennae were transported one-by-one to the Array Operations Site. At the end of 2009, a team of ALMA astronomers and engineers successfully linked three antennae at the {{convert|5000|m|adj=on}} elevation observing site thus finishing the first stage of assembly and integration of the fledgling array. Linking three antennae allows corrections of errors that can arise when only two antennae are used, thus paving the way for precise, high-resolution imaging. With this key step, commissioning of the instrument began 22 January 2010.

On 28 July 2011, the first European antenna for ALMA arrived at the Chajnantor plateau, 5,000 meters above sea level, to join 15 antennae already in place from the other international partners. This was the number of antennae specified for ALMA to begin its first science observations, and was therefore an important milestone for the project.<ref>{{cite news|title=European ALMA antenna brings total on Chajnantor to 16|url=http://www.eso.org/public/news/eso1127/|access-date=29 July 2011|newspaper=ESO Organisation Release|date=28 July 2011}}</ref> In October 2012, 43 of the 66 antennae had been set up.