Origins Testbed: capturing the dynamics and control of future space-based telescopes

We describe a laboratory test article developed to capture the dynamics and control problems anticipated for future space-based telescopes: the Space Interferometry Mission (SIM) and the Next Generation Space Telescopes (NGST ). We motivate the design of the Origins Testbed (OT) by identifying three operational events common to space-based telescopes and requiring the OT to simulate them in a laboratory: large-angle slew, optical capture (alignmen t), and observation. The OT is the first spacecraft-like testbed to include nanometer phasing and a large-angle slew capability in the presence of spa cecraft-like disturbances. The OT is discussed in detail, including the tes tbed's dynamics and control sensors and actuators, with particular emphasis on the optical system. We present the necessary optics to capture the phas ing of SIM and NGST using three interferometer channels. Pointing optics ar e detailed, with a description of an implemented spiral-based autoalignment algorithm. Initial slew control is discussed, and experimental results are presented. Future experiments performed on the OT will provide critical he ritage for control techniques to be implemented on SIM and NGST. (C) 2000 s ociety of Photo-Optical instrumentation Engineers. [S0091-3286(00)03106-8].