A few days ago, the NASA sent a rover to Mars to conduct research. One would expect the body to use some kind of high processor technology for this rover. Indeed, NASA technically uses one specialized processor to power the Perseverance rover, which, however, is not far from the consumer electronics and compared to those in circulation about 23 years ago. The magazine NewScientist reports that NASA's Perseverance rover is powered by a PowerPC 750 processor, which was used in its original iMac G3 Apple the 1998.
Name PowerPC may sound familiar, most likely because they are RISC CPUs used by Apple on its computers before switching to Intel.
The processor PowerPC 750 was a single-core, 233MHz processor, and compared to modern multi-core chips with 5.0GHz-plus frequencies, 233MHz is incredibly slow. But the 750 was the first to incorporate "dynamic branch prediction", which is still used in modern processors today. Basically, the CPU architecture makes a thorough guess about the instructions that the CPU will process in order to improve efficiency. The more information that is processed, the easier it is for chip to predict what to do next.
However, NASA could not simply rely on this iMac processor. There is a significant difference between the iMac CPU and the Perseverance rover CPU. THE BAE Systems builds a Radiation-resistant version of the PowerPC 750, named RAD750, which withstands 200.000 to 1.000.000 Rad and temperatures between −55 and 125 degrees Celsius. The Mars does not have the same type of atmosphere as the Earth, which protects us from the sun's rays. Therefore, the processor must have specific specifications in order to withstand the special conditions and allow NASA's Perseverance rover to do its job. Each one costs over $ 200.000, so an extra is required protection.
But why would NASA want to use a processor from the 1990s? According to experts, the choice has nothing to do with cost. Just them old processors are the best for the job they want researchers, because they are reliable. NASA's Orion spacecraft, for example, also used the same RAD750 processor.
""Compared to the Intel Core i5 on your laptop, it's much slower; it's probably not faster than your smartphone." said NASA's Matt Lemke in 2014. "But we are not so concerned about speed as the durability and reliability. I must be sure that it will always work".
From this perspective, it makes sense for NASA to choose an older one technology. The body has spent $ 2,7 billion for mission to Mars, therefore must be based on technology that is reliable enough to withstand time and special conditions. The RAD750 processor currently powers about 100 satellites orbiting the Earth, as well as various military satellites and there has never been a problem.