Why today's spacecraft still run on 1990s processors

It takes years to prepare and test computers for space missions. In the meantime, processor technology advances by light years.
Written by Joe McKendrick, Contributing Writer

Many of the processors running today's spacecraft are the same that were found in our PCs and laptops. The only problem is that many of the processors powering essential spacecraft functions now date back to the 1990s.

The challenge for spacecraft systems designers is that the amount of testing and prep required to get a system ready for spaceflight often takes years, as explained by The Register's Shaun Dormon. Before you know it, the processor market has blazed ahead by another light year or two. (Remember Moore's Law -- processing power doubles every two years.)

"Once a chip has been made ready for space use, it’s long past its Earthly sell-by date," Dormon writes. In the long run, these chips may fail due to some of the harsh conditions of space, such as "constant bombardment by ionized hydrogen radicals - effectively just free protons - and energetic electrons that are ejected as Solar Wind, the result of which is the minute degradation of nanoscale circuits."

Plus, processing is slower -- at 1999 speeds.

Examples of older chipsets powering today's spacecraft include NASA’s Mars-based Curiosity rover, which uses a RAD750 computer from BAE Systems. The RAD750 is based on the PowerPC 750 chip once found in Apple’s G3 iMac, which debuted in 1997, Dormon says. Also, the Hubble Space Telescope is running on an Intel 486 chip, installed in 1999.

The CPU Shack provides a nice overview of the chipsets powering most well-known (and not so well known) spacecraft. Of note is the International Space Station, which has several computers, with the most important being command computers which use the Intel i386 -- which was first released in 1985. The Space Shuttle, retired last year, also ran many essential functions on the i386 chipset.

There are two ways to look at this: Perhaps the use of older processors this may be worrisome for the staying power of spacecraft. But it also is a testament to the staying power of some leading processor products. CPU Shack also notes that the processors used in space need to pass extremely rigorous testing. Also, most spacecraft use many CPUs, and have many different subsystems.

(Photo: NASA via Wikipedia.)

This post was originally published on Smartplanet.com

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