Tham khảo tài liệu 'mems and microstructures in aerospace applications - robert osiander et al (eds) part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 170 MEMS and Microstructures in Aerospace Applications mirror-shape stability and fabrication tolerances are of key concern to a system designer. To this end preliminary MEMX devices were evaluated in terms of angular jitter focal spot stability and open and closed-loop response versus laser transmitter power at both ambient air and lower partial pressures. The applicability and scalability of this technology to multiaccess terminals was also considered and appears to be readily transferable to a space-qualified design. For most spacecraft platforms micromirrors should be compatible with direct body-mounting because of their high intrinsic bandwidth and controllable damping. Being able to body-mount these devices is highly desirable to take advantage of their low mass which implies spacecraft attitude control would be used for overall coarse pointing. Importantly these optical beamsteerers are highly miniaturized very lightweight require very little prime electrical low power and are scalable to 2-D multichannel point-to-multi-point links. Initially a key concern about the MEMS micromirror performance in a space environment was the effect of partial vacuum on heat dissipation from the transmitting laser beam and on the degree of mechanical damping of the mirror. It is important that the beamsteering controller be critically damped under suitable partial or full atmospheric vapor pressure. In addition a trade-off between the optical power required to support the link and the degree of thermal heat loading experienced by the mirror elements under pulsed laser light must also be determined. Furthermore any micromirror curvature change induced by laser heating must be avoided. To this end preliminary optical dynamic and thermal measurements of the MEMX micromirrors were made using the optical test bed shown in Figure . Using experimental measurements physical optics modeling and computerbased ray tracing the laser beam quality reflected off a micromirror was .
