Two Russian cosmonauts will have to install International Space Station debris panels another day after their spacewalk took longer than expected, NASA said.

Space station Flight Engineers Oleg Kononenko and Anton Shkaplerov used a 6-hour, 15-minute, spacewalk to move a 46-foot telescoping boom from one docking port to another on the station's Russian segment, the U.S. space agency and the Russian Federal Space Agency's Mission Control Center said.

"Thank you so much for everything you've done," a Russian ground controller radioed in Russian. "You accomplished an enormous task."

The spacewalk was supposed to have included installation of debris shields to the Zvezda Service Module, which provides all the station's life-support systems, the space agencies said, but the cosmonauts ran out of time and the installation will take place on a later spacewalk, officially known as an extravehicular activity, the NASA said.

The Thursday spacewalk was the first for Shkaplerov and third for Kononenko, who has logged 18 hours, 27 minutes of extravehicular activity.

The space station is staffed by three Russians, two Americans and a Dutchman. U.S. Coast Guard Capt. Dan Burbank, a veteran of two space-shuttle missions, is the expedition commander. U.S. chemical engineer Don Pettit, a veteran of a six-month space-station stay and a six-week Antarctic expedition to find meteorites, is a flight engineer.

The space station, continuously occupied for more than 11 years, is maintained at an orbital altitude of 205 miles to 255 miles above Earth. It circles the planet about every 90 minutes and completes nearly 16 orbits a day.

The station is expected to remain in operation until at least 2020.