US astronaut Drew Feustel learned a valuable lesson about being teary-eyed on a spacewalk, according to Nasa, after the Endeavour crew’s third jaunt outside the International Space Station.

“Tears in space don’t run down your face,” he said, according to lead spacewalk officer Allison Bollinger who described the problem astronaut Feustel encountered when out on the spacewalk with astronaut Mike Fincke.

“They actually kind of conglomerate around your eyeball,” astronaut Bollinger recounted.

The problem occurred toward the end of the spacewalk by the two American astronauts who arrived at the orbiting lab along with a six-member crew aboard the shuttle Endeavour 10 days ago.

After stepping out to work on repairs to the Russian side of the station, Mr Feustel discovered some of the anti-fog solution he had buffed on to the interior of his helmet was flaking off.

“We have seen this happen a couple of times in the past where if you are not careful about buffing the anti-fog just the right amount, that it can tend to flake off every once in a while and get in the crew member’s eye,” said Mr Bollinger.

“The anti-fog is just off-the-shelf dishwashing soap. So if you have ever had soap in your eye, you know how that feels.”

Mr Feustel, who has completed several spacewalks since becoming an astronaut in 2000, was able to wiggle down far enough in his spacesuit to make use of a spongy device called a Valsalva that is typically used to block the nose in case a pressure readjustment is needed.

“He was able to rub his eye against the Valsalva device to get the tear free,” Mr Bollinger said.

The rest of the six hour, 54 minute spacewalk was routine, Nasa said. Scheduled tasks to complete an external wireless antenna system and mend parts of the Russian side of the space station went ahead as planned.

A final spacewalk by two Endeavour astronauts outside the orbiting research station is set for today.

It will mark the last time US astronauts arriving on board the space shuttle step out for a spacewalk at the lab. A spacewalk is planned for the Atlantis mission in July, but it will performed by International Space Station crew, not by US astronauts who arrive on the shuttle Nasa said.

The Endeavour mission, STS-134, is the second to last for the American shuttle programme. After Atlantis’s planned launch in July, the three-decade US programme will end and the shuttles will become museum pieces.

A new pre-spacewalk exercise regimen, known informally as the slow motion hokey pokey and consisting of light exercises and breathing instead of an overnight campout in an airlock, was judged a resounding success.