This location was chosen for its high elevation and low humidity, factors which are crucial to reduce noise and decrease signal attenuation due to Earth's atmosphere.

[2][3] ALMA is an international partnership amongst Europe, the United States, Canada, Japan, South Korea, Taiwan, and Chile.

[9] The array has much higher sensitivity and higher resolution than earlier submillimeter telescopes such as the single-dish James Clerk Maxwell Telescope or existing interferometer networks such as the Submillimeter Array or the Institut de Radio Astronomie Millimétrique (IRAM) Plateau de Bure facility.

The antennae can be moved across the desert plateau over distances from 150 m to 16 km, which will give ALMA a powerful variable "zoom", similar in its concept to that employed at the centimeter-wavelength Very Large Array (VLA) site in New Mexico, United States.

By using smaller antennae than the main ALMA array, larger fields of view can be imaged at a given frequency using ACA.

Following mutual discussions over several years, the ALMA Project received a proposal from the National Astronomical Observatory of Japan (NAOJ) whereby Japan would provide the ACA (Atacama Compact Array) and three additional receiver bands for the large array, to form Enhanced ALMA.

The components designed and manufactured across Europe were transported by specialist aerospace and astrospace logistics company Route To Space Alliance,[11] 26 in total which were delivered to Antwerp for onward shipment to Chile.

General Dynamics C4 Systems and its SATCOM Technologies division was contracted by Associated Universities, Inc. to provide twenty-five of the 12 m antennae,[14] while European manufacturer Thales Alenia Space provided the other twenty-five principal antennae[15] (in the largest-ever European industrial contract in ground-based astronomy).

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.

At the end of 2009, a team of ALMA astronomers and engineers successfully linked three antennae at the 5,000-metre (16,000 ft) elevation observing site thus finishing the first stage of assembly and integration of the fledgling array.

By the summer of 2011, sufficient telescopes were operational during the extensive program of testing prior to the Early Science phase for the first images to be captured.

On 11 August 2014, astronomers released studies, using the Atacama Large Millimeter/submillimeter Array (ALMA) for the first time, that detailed the distribution of HCN, HNC, H2CO, and dust inside the comae of comets C/2012 F6 (Lemmon) and C/2012 S1 (ISON).

[30] ALMA participated in the Event Horizon Telescope project, which produced the first direct image of a black hole, published in 2019.

[36][37] The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile.

Activates for operating the ARC have also divided into the three main regions involved (Europe, North America and East Asia).

The European ARC (led by ESO) has been further subdivided into ARC-nodes[40] located across Europe in Bonn-Bochum-Cologne, Bologna, Ondřejov, Onsala, IRAM (Grenoble), Leiden and JBCA (Manchester).

[41] The Atacama Compact Array, ACA, is a subset of 16 closely separated antennae that will greatly improve ALMA's ability to study celestial objects with a large angular size, such as molecular clouds and nearby galaxies.