Brain Surgery Repairs Hubble Telescope

Space shuttle Discovery’s master mechanics stepped outside Thursday and, working amid floating cables and connectors, replaced the Hubble Space Telescope’s antiquated computer with a newer model.

“The brains of Hubble have been replaced,” astronaut John Grunsfeld announced from inside the shuttle as the two spacewalkers outside completed the job.

With the door of the Hubble swung open wide like the hood of a car, Michael Foale and Swiss astronaut Claude Nicollier, making his first spacewalk, hovered next to each other as they pulled out the old computer and put in the new.

It was the second of three planned spacewalks to fix the $3-billion telescope, which has been out of commission for a month.

Besides the computer work, the astronauts replaced one of the Hubble’s three fine-guidance sensors, piano-sized instruments used to point the telescope.

It was slow going: Nicollier tried to guide the bulky box into its tight slot as Foale floated nearby, telling him which way to push. Both men finally had to shove it in.

Foale and Nicollier, both astrophysicists, were awe-struck gazing up at the four-story telescope jutting out of the shuttle cargo bay, more than 370 miles above Earth.

“Well, Claude, what do you think?” Foale asked.

“Beautiful. Beautiful,” Nicollier murmured.

The installation of the computer fell to Foale, who is a software programming expert. He had to be extra careful not to bend the approximately 1,000 fragile gold pins in the computer cables.

A check showed that all the connections were good.

“The Hubble not only has new brains, it’s thinking,” Mission Control said.

The Hubble’s old computer is based on an Intel 386 microchip. The new one is an Intel 486--20 times faster with six times the memory.

Actually, there are three identical computers in the replacement box, only one of which is used at any given time. Each has 2 megabytes of memory.

“We don’t do Windows and we don’t have disks and we don’t do Internet, and the old computer only had a 10th of a megabyte, so this is a major increase in capability,” said Hubble manager John Campbell.

NASA tests computers for four years before flying them in space to ensure they can withstand the harsh cosmic radiation--thus the gap in technology.

One last spacewalk is planned for today to put in a radio transmitter and data recorder and hang steel sunshields on Hubble.

Hubble went to sleep on Nov. 13 when too many gyroscopes failed.