The steady advance of technology allows sensing the environment at an always increasing level of accuracy. As a result, the operating conditions to guarantee an appropriate level of performance of such precise instrumentation are becoming more stringent, particularly for optical payloads. Spacecraft have traditionally granted a stable and noise-free environment from which high-precision measurements can be conducted. This has been the case for high-resolution space-based telescopes and a wide variety of remote sensing missions. An essential factor in achieving the levels of stability that high-precision instrumentation require is to have a dimensionally stable structure. Traditionally, acceptable levels of dimensional stability have been reached based only on passive methods, i.e. by developing an adequate structural design built with materials that have high stiffness and low coefficients of thermal expansion. However, as higher levels of stability are required, traditional methods to counteract the effects of acting perturbations are approaching their limits. A particular type of perturbations that can introduce significant dimensional changes on the structure are perturbations of thermal origin. These change the temperature field in the structure and, as a result, the displacement between different points. Recent missions exemplify that the magnitude of these distortions is becoming more problematic and, thus, better methods of dimensional stabilization are required. This work presents an alternative to the traditional passive approach. The presented method relies on the controlled application of heat on a structure in order to modify its temperature field, and as a consequence, the arising distortions. This control framework is enabled by a frequency-domain formulation of the thermomechanical model of the structure, derived in turn through the finite element method. Based on this formulation, thermomechanical transfer functions between temperature and displacement are obtained and a controller can be derived. The sensor and actuator strategies to implement the presented control approach are also presented. A simulation environment is developed to assess the dimensional stability that could be achieved with this method. This takes into account the major factors that in reality could contribute to a performance decrease, including the sensor and the actuator uncertainties. The achieved stability performance under different scenarios is assessed, which proves that the presented method can potentially provide dimensional stability beyond what is passively possible. It is expected that this method can contribute to enabling new types of high-performance space missions with stringent dimensional requirements including higher-resolution telescopes, laser communications satellites and formations of spacecraft for space-based interferometry.    «

The steady advance of technology allows sensing the environment at an always increasing level of accuracy. As a result, the operating conditions to guarantee an appropriate level of performance of such precise instrumentation are becoming more stringent, particularly for optical payloads. Spacecraft have traditionally granted a stable and noise-free environment from which high-precision measurements can be conducted. This has been the case for high-resolution space-based telescopes and a wide va...    »