Design of mirror mount for improved opto-mechanical performance.
- Paper number
IAC-08.C2.2.4
- Author
Mr. Chirag Dewan, Indian Space Research Organization (ISRO),SAC, India
- Coauthor
Mr. D. Subrahmanyam, Indian Space Research Organization, SAC, India
- Year
2008
- Abstract
ResourceSat-1 satellite was launched in 2003 with a mission of exploring natural resources by earth observation. LISS-IV camera was one of the sensors to acquire images for cartography with 5m resolution. This 3-mirror anastigmatic telescope was designed with metal structure. The mirrors were held by 3-blade flexure mounts on metal structure. The optical performance of this camera system was required to be enhanced for the new mission with higher capabilities like 10-bit digitization.
A new mounting technique for mirrors are worked out to enhance overall optical performance of the camera system. The previous blade mount design is now replaced with hexapod mounting technique. 3 blades are now replaced with 3 independent metal components which are having virtual ball joints fabricated in their physical shapes. The virtual ball joints support mirror in virtual free-free condition. The design is optimized for stresses in mirrors against optical performance parameters like surface figure distortion.
The new design allows mirror mounting without adding any assembly stress and thus the degradation in surface figure due to assebly distortion is avoided. In addition to this, surface figure distortion due to thermal stresses in mirror is also well taken care of. Stresses in mirrors are less under launch loads.
Eventually, overall system MTF improves by approximately 15
New desing of mirror mounts will help improve overall opto-mechanical performance of the next system.
- Abstract document
- Manuscript document
(absent)