Replacing the K1 dome shutter drive system

The W. M. Keck Observatory recently completed an upgrade to the Shutter Drive System on the Keck 1 dome. Due to three major failures on the shutters we decided to undertake a multimillion dollar, multiyear effort to upgrade the drive system. The intention was to increase the system safety factors, to prevent potential problems, to improve maintenance of the system, and to add the capability of the shutter being used as a tracking windscreen, reducing wind effects on the telescope, thereby improving observing. Our solution included the replacement of the drive system with a new drive train and control mechanism, as well as various modifications to existing infrastructure. We'll describe the project from inception to conclusion, and illustrate various approaches helpful to managing this large project while minimizing observatory downtime. We'll discuss control schemes, safety features, failure mode investigations and some heat dissipation concerns. We'll also describe work scheduling, and some prototyping options helpful to ensure success of the project. Finally we'll present some lessons learned from retrofitting a large, essential system of an operating telescope.