ALMA – the Atacama Large Millimeter Array – will be a single instrument
composed of 64 high-precision antennas located on the Chajnantor plain
of the Chilean Andes in the District of San Pedro de Atacama, 16,500
feet (5,000 meters) above sea level. ALMA’s primary function will be
to observe and image with unprecedented clarity the enigmatic cold
regions of the Universe, which are optically dark, yet shine brightly
in the millimeter portion of the electromagnetic spectrum.

The Atacama Large Millimeter Array is an international astronomy
facility. ALMA is an equal partnership between Europe and North
America, in cooperation with the Republic of Chile, and is funded in
North America by the U.S. National Science Foundation (NSF) in
cooperation with the National Research Council of Canada (NRC), and in
Europe by the European Southern Observatory (ESO) and Spain. ALMA
construction and operations are led on behalf of North America by the
National Radio Astronomy Observatory (NRAO), which is managed by
Associated Universities, Inc. (AUI), and on behalf of Europe by ESO.

“The U.S. National Science Foundation joins today with our North
American partner, Canada, and with the European Southern Observatory,
Spain, and Chile to prepare for a spectacular new instrument,” said Dr.
Rita Colwell, director of the U.S. National Science Foundation. “The
Atacama Large Millimeter Array will expand our vision of the Universe
with ‘eyes’ that pierce the shrouded mantles of space through which
light cannot penetrate.” Wayne Van Citters, Division Director for the
NSF’s Division of Astronomical Sciences represented Dr. Colwell at this

“ALMA will be a giant leap forward for our studies of this relatively
little explored spectral window towards the Universe,” said Dr.
Catherine Cesarsky, Director General of ESO. “With ESO leading the
European part of this ambitious and forward-looking project, the impact
of ALMA will be felt in wide circles on our continent. Together with our
partners in North America and Chile, we are all looking forward to the
truly outstanding opportunities that will be offered by ALMA, also to
young scientists and engineers.”


ALMA will receive millimeter and sub-millimeter wavelength electro-
magnetic radiation from space. This portion of the spectrum, which is
more energetic than most radio waves yet less energetic than visible
and infrared light, holds the key to understanding a great variety of
fundamental processes, including planet and star formation, and the
formation and evolution of galaxies and galaxy clusters in the early
Universe. The possibility to detect emission from organic and other
molecules in space is of particularly high interest.

“ALMA will push the limits of engineering to provide a telescope array
at a fantastic site for astronomers to peer at the beginnings of the
Universe, galaxies, stars and planets, and perhaps even life,” said Dr.

Fred K.Y. Lo, director of the National Radio Astronomy Observatory

The millimeter and sub-millimeter radiation that ALMA will study is
able to penetrate the vast clouds of dust and gas that populate
and intergalactic space, revealing previously hidden details about
astronomical objects. This energy, however, is blocked by atmospheric
moisture here on Earth. To conduct research in this critical portion
of the spectrum, astronomers need a site that is very dry, and preferably
at a very high altitude where the atmosphere is thinner. Extensive tests
showed that the sky above the high-altitude Chajnantor plain in the
Atacama Desert has the unsurpassed clarity and stability needed to
perform efficient observations with ALMA.


ALMA will be the highest altitude, full-time ground-based observatory
in the world.

Work at this altitude, however, is very challenging. To help ensure
the safety of the scientists and engineers at ALMA, operations will be
conducted from the Operations Support Facility, a compound located
close to the cities of Toconao and San Pedro de Atacama, which is at a
more comfortable 2,900 meters (9,500 feet) above sea level.

Phase 1 of the ALMA Project, which included the design and development,
was completed in 2002.

The beginning if Phase 2 of this project happened on February 25, 2003,
when the NSF and ESO signed an agreement to construct and operate ALMA.
Construction will continue until 2012; however, initial scientific
observations are planned in 2007, with a partial array of the first
antennas. ALMA’s operation will progressively increase until 2012 with
the installation of the remaining antennas. The entire project will
cost approximately $552 million U.S. (in FY 2000 dollars).

Earlier this year, the ALMA Board selected Professor Massimo Tarenghi,
formerly manager of ESO’s VLT (Very Large Telescope) Project, to become
ALMA Director. He is confident that he and his team will succeed. “We
may have a lot of hard work in front of us,” he said, “but all of us in
the team are excited about this unique project. We are ready to work for
the international astronomical community and to provide them in due time
with a unique instrument allowing trailblazing research projects in
many different fields of modern astrophysics.”


ALMA will be composed of 64 high-precision antennas, each 12 meters in
diameter. The ALMA antennas can be repositioned, allowing the
telescope to function much like the zoom lens on a camera. At its l
argest, ALMA will be 14 kilometers (8.7 miles) across. This will allow the telescope
to observe the fine-scale details of astronomical objects. At its
smallest, approximately 150 meters (492 feet) across, ALMA will be able
to study the large-scale structures of these same objects.

ALMA will function as an interferometer, meaning it will combine the
signals from all its antennas (two at a time) to simulate a telescope
the size of the distance between the antennas.

With 64 antennas, ALMA will generate 2016 individual antenna pairs
(baselines) during its observations. To handle this much data, ALMA
will rely on a very powerful, specialized computer called a correlator, which will perform 16,000 million-million operations per second.

Currently, the two prototype ALMA antennas are undergoing rigorous
testing at the NRAO’s Very Large Array site, near Socorro, New Mexico.


For this ambitious project, ALMA has become a joint effort among
several nations and scientific institutions. This will be the first truly
global project of ground-based astronomy, an essential development in
view of the increasing technological sophistication and the high costs
of the front line astronomy installations.

“Today marks the official start of construction,” said Dr. Colwell.
“But the ALMA partnership also breaks ground with a novel collaboration
that ensures equal access by astronomers on at least three continents.
International partnerships are quickly becoming the norm of the
millennium, enabling organizations and nations to combine funds to
achieve greater scientific capability. NSF is proud to participate in
the creation of an instrument that will provide unprecedented power for
science and immeasurable knowledge for all.”

The National Radio Astronomy Observatory is a facility of the National
Science Foundation, operated under a cooperative agreement by
Associated Universities, Inc.


An artist’s concept of the array is located at:

A brochure on ALMA is available in .pdf format at: