The Arcosanti Critical Mass Master Plan is distinguished from the page: critical mass within Arcology Theory (This linked page goes more in-depth into the social theory of critical mass within the process of transforming Arcosanti into an Arcology).
In 2000 the most recent revision of Arcosanti's Master Plan was completed. During this time, Soleri came up with Arcosanti 5000, a plan for having 5000 people living and working at Arcosanti in the fullest realization of the Arcology vision at Arcosanti.
Included in that larger plan was an intermediate stage that included the scaling up of existing site activities and function to create what Soleri termed a Critical Mass of activities on the site. While the Cosanti Foundation webpage does not go into detail about the reasoning for using the term, it defines Critical Mass within the Arcosanti project as the point by which 10 percent of the project is completed in terms of population. It lists and details several of key structures associated with that stage of development.
Critical Mass includes the following architectural accomplishments:
West Crescent
Teilhard de Chardin Complex
La Loggia
Pizza Piazza
Arcosanti Energy Aprons.
The idea of critical mass is often used in social movement theory. It has been used to describe a decisive uptick of momentum within social movements. The term originally borrowed from physics, describes the reaching of critical mass chain reaction that leads to exponentially rising burst of energy.
So obviously its reflecting a desire is to describe or associate a key aspect or stage of Arcosanti's development with a huge burst of energy. One criticism of this approach is not the use of the word itself which as mentioned above is often used in social movement theory, but rather the very mechanical way it is used without consideration of real life socio-economic considerations of community and organization development.
Indeed reaching critical mass in social movement theory is not necessarily about the number of people involved or the buildings they live or work in, but rather the quality and compelling nature of their experience. It helps to have large numbers of people but the satisfaction of the people are what drives critical mass. Its also about the building of a social architecture with the goal of creating dynamic and interactive human scale environments, lead to the authentic fostering of relationships where people's ideas, thoughts and needs matter.
So if one were to develop an effective strategy for Arcosanti, one would hopefully consider what people might want in order to come to a place like Arcosanti that was wanting to achieve this idea of a critical mass in terms of achieving a certain number of people living there. Hopefully though the organization would not just be thinking about such qualitative things otherwise it might just be mimicking conventional organization behavior that it claims to be wanting to be creating an alternative to.
What might be the things that would lure people to such a place to create this critical mass?
Commitment to Sustainability and Appropriate Technology - Includes a plan for future new construction but also retrofiting existing infrastructure that was not always built with consideration to long term sustainability values
Fostering of Community Spirit - Valuation of community not just in name but in terms of investing in institutions that support community and family development at Arcosanti
Green Business Incubation - Links the financial viability of the project with its residents in a mutually supportive relationship that includes the promoting and incubation of sustainable businesses
Transparency and Accountability - Leadership is not a one way street and the running of Arcosanti needs to be more open and transparent, if it is to be a magnet for socially conscious people looking for a genuine alternative to sprawl and consumerism. Just as we would expect in a typical government or non-profit or even a joint stock corporation. The corporate has to be accountable to it stockholders and at the same level a non-profit should be accountable to its stakeholders.
Understanding key leverage points is important to building momentum so 500 people living at Arcosanti might be a good goal but why 500? Why not 300-500? Why not 150 which is often used as a good building place from which to establish basic amenities. What studies have been done to understand what natural levels exist in the development of communities and to consider in relation to that what critical mass might mean or what might be extrapolated from the social science and its study of human behavior?