Whither Small Satellites
Stuart Eves

Frequently analogised as “the PCs of space”, small satellites continue to evolve rapidly. As a result of their short development times (usually less than two years), they are able to exploit the on-going developments in terrestrial electronic technologies and so can be considered to follow the space equivalent of “Moore’s Law”.

In addition to these technological trends, financial pressures are also likely to favour smaller, low costs systems, with moderate lifetimes, allowing regular technology refresh to maintain competitive levels of performance. The analogy with terrestrial computers works well again here – if your home computer is more than 5 years old, you’re probably looking to replace it with a new machine that will have a faster processor, more memory and that will run the latest software. With modern small satellites the same argument now applies in orbit.

Among the more important technology trends are:-

• Improving detector performance – devices with greater sensitivity and resolution create larger data files and the need for more on-board storage and more data downlink capacity
  
• Increasing processing power – leading to the potential for more on-board computing than is currently performed. This should reduce the overall data rates required from satellites, and hence ease the demand for bandwidth.
  
• Smaller component sizes – leading to physically smaller platforms and increased payload ratios, i.e. more useful payload and less supporting hardware
  
• Increasing levels of networking – both short-range and long range inter-satellite links are expected to become standard, allowing clusters of small satellites to synthesise the performance of larger missions, and also increase the speed of their data delivery through long range links.
  
• More efficient propulsion systems - allowing satellites to operate in lower altitude orbits than has previously been possible.
  
• Increasing agility – allowing satellites to move in a rapid fashion from target to target and so satisfy a greater range of high-timeliness and tactical applications - satellites will no longer be seen as exclusively strategic investments. Agility also allows satellites to operate at a greater range of local times in the day, further extending the scope of surveillance missions to support tactical applications.
  
• Increasing power generation and storage – allowing satellites to provide improved duty cycles and generate greater volumes of higher timeliness data worldwide.
  
• Smaller, more mobile ground stations – requiring the satellites to provide greater support to the link budget via increased power or shorter ranges.