Structural design considerations for the Space Infrared Telescope Facility

Abstract

To assess the design feasibility of the Space Infrared Telescope Facility (SIRTF) and to identify parameters that might impose constraints on performance such as frequencies of vibration, structural concepts for both the telescope and spacecraft are developed and evaluated. Trade studies of key design features are carried out using FEM and analysis. In most cases, the margin of safety was greater than 0.50. An example of stress in the octagonal equipment bus panels is shown. The strap-supported mass is predicted to deflect 6 mm relative to the outer shell when subjected to 8.0 G in the X direction, and to deflect about 5 mm in the Y and Z directions when subjected to 10.0 G. Deflections for the top of the solar panel are predicted to be about 35 mm when subjected to the 10.0 G quasi-static load in the Z direction. The liquid helium tank, thermal isolation, and primary mirror and mount are discussed.