TMT primary mirror segment actuators: from prototyping to production

The Primary Mirror Control System (M1CS) of the Thirty Meter Telescope (TMT) incorporates 1476 precision electromechanical soft actuators that are used to perform closed-loop control of the 492 primary mirror segments in piston, tip and tilt. This paper describes the evolution of the M1CS actuator design from the early concept through several prototype rounds towards a design suitable for production at-scale. It offers insight into how TMT has and continues to meet the unique challenges and opportunities associated with manufacturing across an international partnership, in particular the need for high quality technical oversight and documentation at all stages of the process from prototype development, modeling, drawing production and subsequent assembly, test and verification. Key design decisions, refined through prototyping and testing to ensure optimum performance, reliability and serviceability are highlighted. Insight is given into the activities undertaken by TMT partners and vendors in India, especially as part of the vendor selection and vendor qualification that was undertaken as part of TMT’s Production Qualification Phase (PQP) process.