Low vibration microminiature split stirling cryogenic cooler for infrared aerospace applications

Abstract

The space-borne infrared instrumentation is known to be inherently susceptible to cryocooler induced vibration, the attenuation of which usually relies on active multi-tonal momentum cancellation under supervision of a dedicated controller. In this approach, the typical single-piston expander is actively counterbalanced by a motorized counterbalancer and the typical dual-piston compressor is counterbalanced by actively synchronizing the motion of the opposing moving piston assembly. The feedback signals are usually provided by external vibration sensors (force transducers or accelerometers). Although compliant with the most stringent space requirements, like 0.2N rms over the frequency range 0-1kHz, such a conservative vibration control approach can result in using outdated, oversized, overweight and overpriced cryogenic coolers for some applications. Such a "space heritage" practice becomes increasingly unacceptable for space agencies now operating within tough monetary and time constraints. The authors are advocating the purely passive approach to a vibration control relying on the combined principle of tuned dynamic absorber and low frequency vibration isolator having a potential to outperform the systems of active vibration cancellation with respect to overall system effectiveness. This approach warrants particularly strong consideration for cost-sensitive missions. © 2012 American Institute of Physics.