When someone purchases a new laptop or phone, the first question they receive is "How fast is it?" With on-board processors for satellites, the immediate question is: "Does it still function in deep space?" There is no atmosphere in space to easily cool down the processor, no Apple Genius waiting in the wings to fix everything and no wall outlet to facilitate recharging. In addition, the processor is constantly exposed to radiation and temperature fluctuations. This is why Karel Walters, PhD candidate at the University of Twente, has devised a new chip for European space exploration.
Due to the stringent requirements, it takes a long time to develop a processor. Subsequently, the processor has to last for as long as possible, because it is extremely costly to develop. That is the reason why the processors used in space are often very old in comparison with those used on earth. The average processor in a phone has multiple cores and operates at GHz speeds, while the recent Mars rover Curiosity must operate with a simple single core running at 200Mhz.
Internet operates slowly in space
The demand is great for a new European chip for satellite data processing. Launches are very costly, and agencies like the ESA want to obtain as much data as possible for that investment. Therefore, the instruments on board satellites are increasingly more accurate and more of them are being included in every satellite. The area in which researchers have been able to effect little change is the speed of the satellite's connection. While people have grown accustomed to a 100Mbit internet connection at home that is available around the clock, researchers must make do with a connection in space of only a few Mbits that is available for a mere few hours a day.
European processor
In order to collect and transmit as much data as possible, despite the limitations, a new European processor is required; the previous European processor is from the early 90s and is a 20Mhz signal processing processor (TSC21020F). Current military export regulations of the United States make it very difficult to use American processors on board European satellites.
New chip
"In my PhD thesis, I present a new (prototype) chip which has been developed, together with Recore Systems, on assignment by ESA-ESTEC (European Space Agency and European Space Research and Technology Centre). Two processors designed specifically for signal processing (Xentium) are connected via a network-on-chip (NoC). All of the high speed interfaces are connected to the NoC in order to move the data quickly. There are now possibilities to generate more processing power, without necessitating a redesign, as well as to run relatively easy legacy software on the chip. We are currently looking at the feasibility of producing a chip that is fully protected against radiation; this would enable modern missions to Jupiter using European technology.
More information
The PhD thesis Versatile Architectures for onboard payload signal processing is available upon request. The research was conducted at the Centre for the Telematics and Information Technology (CTIT) of the University of Twente.
