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The Atacama Large Millimeter/submillimeter Array (ALMA) is a joint project between astronomical organizations in
Europe, North America, and East Asia, in collaboration with the Republic of Chile. ALMA consists of 54 twelve-meter
antennas and 12 seven-meter antennas operating as an aperture synthesis array in the (sub)millimeter wavelength range.
Assembly, Integration, and Verification (AIV) of the antennas was completed at the end of the year 2013, while the final
optimization and complete expansion to validate all planned observing modes will continue. This paper compares the
actually obtained results of the period 2008-2013 with the baselines that had been laid out in the early project-planning
phase (2005-2007).
First plans made for ALMA AIV had already established a two-phased project life-cycle: phase 1 for setting up
necessary infrastructure and common facilities, and taking the first three antennas to the start of commissioning; and
phase 2 focused on the steady state processing of the remaining units. Throughout the execution of the project this lifecycle
was refined and two additional phases were added, namely a transition phase between phases 1 and 2, and a closing
phase to address the project ramp-down. A sub-project called Accelerated Commissioning and Science Verification (ACSV)
was carried out during the year 2009 in order to provide focus to the whole ALMA organization, and to
accomplish the start-of-commissioning milestone. Early phases of CSV focused on validating the basic performance and
calibration. Over time additional observing modes have been validated as capabilities expanded both in hardware and
software.
This retrospective analysis describes the originally presented project staffing plans and schedules, the underlying
assumptions, identified risks and operational models, among others. For comparison actual data on staffing levels, the
resultant schedule, additional risks identified and those that actually materialized, are presented. The observed
similarities and differences are then analyzed and explained, and corresponding lessons learned are presented.
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