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Precautions

During a spacewalk, all that stands between an astronaut and death is the space suit that provides the essentials of life—oxygen to breathe, atmospheric pressure and temperature control.

Not surprisingly, no one takes chances with the suit. Spacewalking astronauts move slowly and carefully as they go about their assigned tasks, taking care to avoid anything that could snag or tear the suits, which could result in a potentially fatal loss of pressurization.

In fact, every item they come in contact with has been carefully checked before launch to ensure there are no sharp edges or other hazards that could damage the suit.

However, not all spacewalks go exactly as planned and sometimes astronauts end up working in places where they were never intended to be. This happened on STS-97 in December 2000, during a flight on which Canadian astronaut Marc Garneau was responsible for coordinating three spacewalks done by his crewmates, Joe Tanner and Carlos Noriega.

The crew of STS-97 installed a pair of large solar panels that will supply electricity to the Space Station. The wing-like structures, which were launched folded up like an accordion, were supposed to unfurl into taut, flat panels. But when one of the panels extended, two tension cables slipped from their pulleys, leaving the panel slack. There was concern that it could being damaged during Station operations.

When Tanner and Noriega were sent out to fix the cables, they were working in an area that was never designed for spacewalks. Some of the surfaces had sharp edges and they had take care to keep their gloves away from the braided-wire cables. Instead, they used a tool that looked like a large crochet hook to move the cables back onto the pulleys.

They almost experienced another risk of spacewalks—the loss of a tool. The tether that secured the hook to Tanner’s suit broke, but he held onto it and quickly attached another line. Loose tools are a serious hazard in space; since they’re travelling at roughly 27,000 kilometres per hour, they can easily penetrate a space suit or even a spacecraft.

All these precautions have paid off—no astronaut has been killed or seriously injured doing a spacewalk since they were first performed in the 1960s.