NASA bills the International Space Station as “the most complex scientific and technological endeavor ever undertaken.”

Perhaps that is so, but its guts are so 1980s.

That's because the 44 primary computers that do everything from guide the station around Earth at 17,000 mph to monitor for fires are powered by Intel 386 processors, first built in the mid-1980s, with a clock rate of 16 megahertz. To put that in perspective, today's processors are measured in gigahertz, a speed increase by a factor of 1,000.

Needless to say, the task of maintaining the network of computers on the station humming along is more difficult than, say, putting together a home network.

The station has components from the United States, Russia, Japan, Canada and Europe, each with their own hardware and software. Each system must “talk” to one another and crashes can be a bit more problematic than losing the Internet until a technician can arrive.

One such crash did occur in 2001, during a space shuttle mission to the station.

Of all the station's computers, the command-and-control computer, which has two back-ups, serves as the “brains” of the network. The first command-and-control computer failed, then the first back-up began operating erratically and then, finally, all three failed.

Lot of hard work

With Endeavour docked to the station, the crew re-routed its communications through the shuttle and eventually swapped another onboard computer into the command-and-control slot. It turned out to be a hard drive issue.

“That took some life off us,” admits Michael Suffredini, the station's program manager.

But since that incident the station's computers have largely functioned without incident.

“It's not darn good luck that we've had success, it's the result of a lot of hard work up front,” Suffredini said.

A lot of the hard work can be credited to a Boeing software laboratory in Clear Lake, a few miles from Johnson Space Center, that's next door to the large swimming pool where astronauts train for spacewalks.

Inside the lab there's a mock-up of the computer systems on board the station where all software is tested before it is sent to the station. Every new component that's sent up to the station is tested there first to ensure it will work smoothly in space.

“This is basically the space station on the ground,” explained Jose Pinero, a lab manager during a recent tour.

Upgrade to the '90s

The lab is now testing a software for version 10 of the station's core programming, which is roughly analogous to an aircraft's flight computer. NASA expects to fly this software upgrade, which entails more than 700,000 lines of code, in 2011.

That's the time when NASA also intends to upgrade the station's primary computers — to basic Pentium processors. That's about a five-fold increase in processing power, with considerably more memory.

“That's smokin',” quipped Steve Cox, another manager at Boeing's lab. “We'll be all the way up to 1990s technology.”

eric.berger@chron.com