  A popular analogue used in the space domain is that of historical building
projects, notably cathedrals that took decades and in some cases centuries to
complete. Cathedrals are often taken as archetypes for long-term projects. In
this article, I will explore the cathedral from the point of view of project
management and systems architecting and draw implications for long-term
projects in the space domain, notably developing a starship. I will show that
the popular image of a cathedral as a continuous long-term project is in
contradiction to the current state of research. More specifically, I will show
that for the following propositions: The cathedrals were built based on an
initial detailed master plan; Building was a continuous process that adhered to
the master plan; Investments were continuously provided for the building
process. Although initial plans might have existed, the construction process
took often place in multiple campaigns, sometimes separated by decades. Such
interruptions made knowledge-preservation very challenging. The reason for the
long stretches of inactivity was mostly due to a lack of funding. Hence, the
availability of funding coincided with construction activity. These findings
paint a much more relevant picture of cathedral building for long-duration
projects today: How can a project be completed despite a range of uncertainties
regarding loss in skills, shortage in funding, and interruptions? It is
concluded that long-term projects such as an interstellar exploration program
can take inspiration from cathedrals by developing a modular architecture,
allowing for extensibility and flexibility, thinking about value delivery at an
early point, and establishing mechanisms and an organization for stable
funding.
