Surface distortions of a 4-meter segmented primary mirror subjected to thermal distributions

A new type of space telescope program is developing technology which is to be used in the design of a 4-meter segmented mirror telescope. One acceptable configuration being considered for the primary mirror is a lightweight honeycomb sandwich structure segmented mirror. There can be optically-significant distortions when the primary mirror is exposed to typical thermal environment. This paper discusses the surface distortions subjected to thermal distributions Finite element analyses were performed to predict the optical surface distortions of the 4-meter primary mirror due to the effects of thermal variations. The temperature patterns were described by a least-squares fit to a polynomial expression, and the polynomial was then used to predict temperature patterns. The finite softwares were also used to analyze cases of axial gradients, radial gradients and the local thermal gradients etc. The result from the finite element analysis is analyzed, and is also presented.