Spacewalk halted after suit problem

Two US Shuttle astronauts from the Endeavour cut short their spacewalk and hurried back to the safety of the international space station (ISS) after a spacesuit problem caused rising carbon dioxide levels for one of them.

Nasa chiefs stressed that spacewalker Christopher Cassidy was never in any danger and experienced no symptoms of carbon dioxide build-up. The trouble happened in Wednesday's spacewalk, the third for shuttle Endeavour's crew.

Mission Control notified the crew five hours into the spacewalk that the canister for removing or 'scrubbing' carbon dioxide from Cassidy's suit did not seem to be working properly.

Abort EVA

Flight controllers wanted him back inside as quickly as possible, to mitigate against the possibility of a complete failure of the ;scrubber;. This meant that fellow spacewalker David Wolf had to go in too because safety rules covering EVAs require that these exercises be carried out by no less than 2 astronauts.

The battery replacement work outside the space station was left unfinished. Only two of the four new batteries ended up being installed.

Heading for the Hatch

Cassidy immediately headed for the hatch. He waited there for Wolf, who was further out on the space station. Their work site was on the far left side of the orbiting complex, along the framework that holds the huge solar wings and more than 150 feet from the hatch.

"I'm just going to sit here and I'm going to wait for Dave and enjoy the view," Cassidy said. What a great idea and its something that all astronauts love to do on EVA, look down on Mother Earth as she spins below them. The biggest distraction on an EVA is often the sheer beauty and wonder of being outside in the vacuum of space, with nothing between you and the beautiful blue Earth.

A view of Earth from Space

The view from inside the Shuttle or the ISS is much more restricted because of the size of the windows or 'viewing panes'. Its a really unique experience for an astronaut to absorb that sensational panoramic view.

In no time and without fuss, both men were safely back inside the ISS and the spacewalk was over 30 minutes after Mission Control's initial call to cut it short. It ended up lasting six hours, a half-hour shorter than planned. The unfinished battery work will be added to Friday's spacewalk, the fourth of five planned for this mission.