The proposed Space Interferometry Mission (SIM) spacecraft carries high resolution stellar interferometers for micro-arc- second accuracy astrometric measurements. These stellar interferometers require picometer accuracy one dimensional metrology gauges, surface metrology gauges and 3-dimensional metrology gauges. The absolute metrology gauges required by these interferometers can be considerably less accurate due to the careful design of the astrometric interferometers on the spacecraft. Open-faced, hollow corner cube retro-reflectors are used as fiducials in the one-dimensional relative and absolute metrology gauges and the 3-dimensional metrology gauge. The diffraction caused by the assembly and the component defects of these hollow retro-reflectors affects the accuracy of these metrology gauges. A simulation quantifying some of the effects of the component and assembly defects of hollow retro-reflectors on the accuracy of a picometer linear metrology gauge is presented. An auto-aligning, 3-dimensional metrology gauge constructed using the sub-picometer linear metrology gauges was described in earlier papers. The functioning automatic alignment and the sub-nanometer, in-air tracking results from this 3-dimensional metrology gauge are presented.

Date Published: 1 October 1997
PDF: 15 pages
Proc. SPIE 3116, Small Spacecraft, Space Environments, and Instrumentation Technologies, (1 October 1997); doi: 10.1117/12.293333

Published in SPIE Proceedings Vol. 3116:
Small Spacecraft, Space Environments, and Instrumentation Technologies
Firooz A. Allahdadi; Firooz A. Allahdadi; Timothy D. Maclay; E. Kane Casani; Timothy D. Maclay, Editor(s)