By Irene Klotz

HOUSTON, Feb 15 (Reuters) - Two shuttle Atlantis astronauts resumed work outside the International Space Station on Friday to attach experiments to the hull of Europe's newly delivered research outpost.

The Columbus module, the European Space Agency's $1.9 billion permanent space laboratory, was launched aboard Atlantis last week and connected to the station on Monday.

Lead spacewalker Rex Walheim and partner Stanley Love flew out of the station's airlock about 8:15 a.m. EST (1315 GMT) to begin the third and final excursion planned during Atlantis' nine-day visit.

The two were paired for the first spacewalk on Monday when German astronaut Hans Schlegel was sidelined by an undisclosed medical condition and Love substituted.

During Friday's spacewalk, Walheim and Love plan to install a European solar observatory and a materials science experiment on the outside of the Columbus laboratory. The module has room for two more external experiments as well.

"It's a little satellite that mounts on the outside of the space station," Love said before his flight. "We will pick it up from the (shuttle's) payload bay and then, riding the (robot) arm, I will carry it up to Columbus."

The astronauts also plan to pick up a broken gyroscope that was replaced on the station during a previous flight and pack it aboard the shuttle for return to Earth.

NASA hoped that Walheim, who was making his fifth spacewalk, and Love, on his second, will have extra time, and prepared several additional jobs for them, including an inspection of a rough spot in a handrail outside the airlock that may be responsible for unexplained rips in astronauts' gloves.

They also will look again at a contaminated solar wing joint that has mired station operations since October. It has been inspected four times previously.

NASA needs to fix the joint so the station can reach full power before the arrival of a large Japanese laboratory known as Kibo later this year. Replacing the faulty equipment, however, will require four to five spacewalks, managers said.

Atlantis carried the first batch of supplies for the repair work, two grease guns and a lubricant. Additional components are scheduled to fly aboard Endeavour next month and on future shuttle missions.

The agency has nine construction missions remaining to complete the $100 billion outpost and two resupply flights planned before the shuttle fleet is retired in 2010. (Editing by Jane Sutton)

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