Integrated SiC/Al lightweight tip-tilt mirror of multi-node laser communications antenna

In order to reduce the range of movement of multi-node laser communication antennas, improve the motion control accuracy of two-dimensional tip-tilt mirror, avoid changing of mirror surface shape caused by the difference material performance between the mirror and the support, a integrated lightweight tip-tilt mirror with a supporting structure was proposed. Integrated design of tip-tilt mirror and support structure was conducted using material of high volume fraction SiC/Al. The thermal and mechanics stability of the mirror surface shape was improved. It can be mounted directly on the elevation axle seat, and the distance between the tip-tilt mirror rotation axis and the surface was shortened to 20 mm. The result of finite element analysis shows that the eigenfrequency of the tip-tilt mirror was of 1 337 Hz. The peak valley value(PV) of tip-tilt mirror surface shape error was better than 0.121, and root mean square value(RMS) was better than 0.031 in the range of (205)℃. Using ZYGO interference to test the mirror surface shape error, test results show that the peak-valley value of tip-tilt mirror surface shape error is better than 0.163 and root mean square value is better than 0.029 in the ambience of (205)℃ Parameter requirement of laser communication antenna for tip-tilt mirror surface shape error /25(RMS) is satisfied.