Miniaturization and Micro/Nanotechnology in Space Robotics
Space is an exciting but fundamentally unfriendly environment for humans. Space robotic systems (robots in orbit, planetary rovers or even satellites) are of great importance to space exploration and perform tasks hazardous or impossible for humans. Using micro and nano technologies in space robotic systems results either in miniaturized systems in terms of volume and mass, while retaining or increasing their capabilities, or in space robots with increased capabilities while retaining their
... due to the nature of their tasks. Examples of miniaturization possibilities for space robots and satellites are given, focusing on the challenges and the enabling technologies. The miniaturization process and the use of advanced nano and microtechnologies in space will have a large beneficial impact in the years to come. or the use of magnetic nanocapsules steered by improved gradient coils provided by Magnetic Resonance Imaging (MRI) systems  . A natural question appears then regarding the degree to which space robotic activities are affected by the miniaturization trend observed on terrestrial applications in general, and more specifically in robotics. One can identify similarities and differences. For example, in robotics the terms micro or nano refer either to the size of the robot itself in terms of micrometers or nanometers, or to the resolution in micrometers or nanometers that this robot has in dealing with its environment. This is because human scale robots that operate in human scale tasks are taken as the basis for comparison. However, in space the scale of tasks is very different and to be more exact, much bigger. Both space exploration and orbital systems scales in terms of orbits, distances, power requirements, etc. are very large compared to the terrestrial human scale. Therefore, despite the evolving miniaturization process, the same terms refer in most cases to different scales of magnitude. This can be seen clearly in the case of nano or even picosatellites, both of which will not qualify as such according to terrestrial robotic terminology. Miniaturization affects space robotic systems in two fundamental ways (a) by reducing the size and weight of components, thus allowing a space robotic system to increase its overall capabilities by maintaining more or less its size, and (b) by reducing its overall size, maintaining the same capabilities. In the first case, the robotic system cannot be reduced in size, because the objects it operates on remain of large size, for example the case of the International Space Station (ISS) robotic manipulators. In the second case, the size can be reduced by maintaining more or less, the initial capabilities; this is the case of nanosatellites. As mentioned earlier, the base scale is large enough so that any size reductions at the device or component scale will not qualify as nanodevices on earth. In the subsequent sections, we examine the existing space robotics applications and classify the robots that are being used. The ways in which these robots can be miniaturized, using our terrestrial experience are addressed. The interesting subject of satellite miniaturization and subsequent proliferation is presented next. Finally, we outline the future trends for miniaturization of space robotics systems and components and address briefly the challenges ahead. Space Robotics Applications Usually the term space robotics is used to characterize semi or fully autonomous, teleoperated exploration and servicing systems, and a few specialized experimental systems. However on a broader sense, almost everything that has been sent into space, integrates a form of automation in some degree, and therefore can be characterized as "automated or robotic". The emphasis here is given to systems that are flight proven, they still operate, or are in the final construction phases and the state-of-the-art in their class.