Two Russian cosmonauts added new equipment outside the International Space Station (ISS), cleaned windows, and took pictures to study its exterior during a 5 and 1/2 hour spacewalk August 10.
The outing was the fourth this year, the 188th in support of the space station, and the 10th in the career of Gennady Padalka, a veteran cosmonaut and grandfather who is serving as commander of the ISS.
In June, Padalka, 57, set the world record for the most time spent in space with a total of 803 days.
His spacewalking partner was Mikhail Kornienko, 55, undertaking his second walkabout in space.
Hours into the rigorous spacewalk, Padalka and Kornienko playfully taunted each other over whose hands were coldest and who had the most spirit, according to live footage broadcast on the websites of the Russian and U.S. space agencies.
The spacewalk 250 miles above the earth's surface ended an hour ahead of schedule after 5 hours and 31 minutes, NASA said.
Padalka and Kornienko installed devices -- known as gap spanners -- on the hull of the station to help "facilitate the movement of crew members on future spacewalks," NASA said.
They also installed fasteners on communications antennas, replaced an aging antenna used for the rendezvous and docking of visiting vehicles at Russian docking ports, and took pictures of locations and hardware on Zvezda and nearby modules.
The astronauts cleaned a porthole window to remove years of dirt left by exhaust fumes from visiting ships.
"They developed a tool kit with two swabs with handles on them. The swabs are kind of a type of terry cloth," spacewalk specialist Devan Bolch said in a NASA video published before the walk.
"It's kind of similar to what you would use on your car headlights, when they get hazy, to clean them."
Floating against the bright blue oceans and white clouds of Earth, the astronauts filmed the outing with small handheld cameras, constantly communicating with each other and Russian mission control outside Moscow.
Once they get out of their spacesuits, they will be able to sample their first bites of space-grown red romaine lettuce that their colleagues have saved for them.
Two U.S. and one Japanese astronaut tasted the lettuce earlier in the day.
NASA astronaut Kjell Lindgren described the leafy greens as "awesome."
"Bon appetit," said Scott Kelly, who is spending one year aboard the ISS with Kornienko, adding the leaf tasted a bit like arugula.
The ability to cultivate food during a trip to Mars in the coming decades will be key to surviving the trip, which could last months or years.
"This payload, and having the ability for us to grow our own food is a big step in that direction," Kelly said.
The next spacewalk around the Russian section is set for January or February 2016, space industry official Alexander Kaleri said.
With reporting by AFP and Reuters