Telescope line-of-sight slew control and agility with non-contact vibration isolation for the large ultraviolet/optical/infrared (LUVOIR) surveyor concept

The Large Ultraviolet / Optical / Infrared (LUVOIR) mission concept intends to determine not only if habitable exoplanets exist outside our solar system, but also how common life might be throughout the galaxy. This surveying objective implies a high degree of angular agility of a large segmented optical telescope, whose performance requires extreme levels of dynamic stability and isolation from spacecraft disturbance. The LUVOIR concept architecture includes a non-contact Vibration Isolation and Precision Pointing System (VIPPS), which allows for complete mechanical separation and controlled force/torque exchange between the telescope and spacecraft by means of non-contact actuators. LUVOIR also includes an articulated two-axis gimbal to allow for telescope pointing while meeting sun-pointing constraints of the spacecraft-mounted sunshade. In this paper, we describe an integrated pointing control architecture that enables largeangle slewing of the telescope, while maintaining non-contact between telescope and spacecraft, in addition to meeting the LUVOIR line-of-sight agility requirement. Maintaining non-contact during slews preserves telescope isolation from spacecraft disturbances, maximizing the availability of the LUVOIR observatory immediately after repositioning maneuvers. We show, by means of a detailed multi-body nonlinear simulation with a model of the proposed control architecture, that this non-contact slew performance can be achieved within the size, weight and power capabilities of the current voice coil actuator designs for the LUVOIR mission concept.