Paper 13094-174
Giant Magellan telescope primary mirror thermal control system design
Abstract
The Giant Magellan Telescope (GMT) primary mirror subsystem (M1S) consists of seven 8.4m diameter borosilicate primary mirrors that must be maintained at the ambient nighttime air temperature as it changes throughout the observing night to prevent seeing effects at the mirror surface. Additionally, thermal gradients internal to the mirrors must be minimized to prevent figure errors caused by distortions of the mirror due to the non-zero thermal expansion coefficient of the glass. To address these requirements, the GMT M1S team is fabricating a prototype thermal control system design that consists of a sub-critical refrigeration system utilizing high pressure (~30 to ~60 bar) CO2 (R744) refrigerant. This paper describes the design and status of the M1 Subsystem Thermal Control (M1STC).
Presenter
GMTO Corp. (United States)
Trupti Ranka is a control systems engineer for the primary mirror subsystem at the Giant Magellan Telescope. Over the past 8 years Dr. Ranka has worked on various aspects of the GMTO primary mirror control systems involving analysis of the active optics and primary mirror support system, firmware development, control software specification, prototype testing, control system characterization and loop tuning.
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