CAPE CANAVERAL — A spacewalking astronaut freed a snagged cable on the inspection boom for shuttle Atlantis on Wednesday, accomplishing the job in a matter of minutes and earning a “superhero” title.

With that behind him, Stephen Bowen whipped through a slew of space station battery replacements.

Bowen and his spacewalking partner, Michael Good, plugged in four new batteries at the International Space Station and even repaired a loose antenna.

The tangled cable had prevented the shuttle astronauts from thoroughly inspecting their ship for any possible damage from last week’s launch. NASA wanted it fixed as soon as possible and added the chore to Wednesday’s spacewalk, the second in three days.

Astronauts working inside moved the end of the 100-foot inspection boom within easy reach of Bowen.

“Keep coming. Another 6 inches or so,” Bowen called out. “Perfect. Stop.”

A few minutes later, he announced: “I have it unsnagged.”

“Well done, superhero,” shuttle pilot Dominic “Tony” Antonelli radioed from inside.

As he was tying the cord back so it wouldn’t get tangled again in camera equipment on the boom, Bowen discovered another wire tie that was already there and causing the cable to get hung up. He slid the loose wire tie into a position Mission Control deemed adequate. Indeed, the camera-tilting system on the boom later checked out fine in a series of tests.

The bulk of the seven-hour spacewalk involved the batteries on the far left side of the space station. The batteries were somewhat cumbersome to handle — 3-foot boxes weighing 375 pounds apiece — but the astronauts managed to replace four of them, one more than planned.

Bowen and Good were running so far ahead that they also squeezed in some antenna work.

They tightened bolts on a spare antenna that was installed earlier in the week, then wiggled it to make sure it was secure.

As the shuttle-station complex soared 220 miles above the South Pacific, the crew inside urged the spacewalkers to take a momentary break and check out the Southern Lights. They managed to catch a glimpse of the aurora.

Two more batteries will be replaced Friday during the third and final spacewalk of Atlantis’ flight.

Atlantis delivered the fresh batteries over the weekend, along with a Russian compartment that was installed Tuesday.

“I don’t think Mission Control could be any more proud,” flight director Emily Nelson said after the spacewalk ended.

The astronauts conducted a curtailed survey of Atlantis on Saturday, the day after liftoff. NASA wanted the cable on the end of the 100-foot inspection boom untangled so the shuttle could be checked properly before it heads back to Earth next week.

Flight controllers have no reason to believe Atlantis was damaged during liftoff by flyaway foam insulation. But they may yet order up a survey while Atlantis is docked to the space station, Nelson said.

At the very least, the astronauts will check the shuttle’s wings and nose cap following Sunday’s undocking for any micrometeorite damage that may have occurred in orbit.

The safety inspections were put in place following the 2003 Columbia disaster. Columbia shattered during re-entry because of a hole in the wing that was left by a slab of broken foam.

Nelson said engineers still do not know how the cable on Atlantis’ inspection boom got tangled.

This is Atlantis’ final flight as the shuttle program winds down. Only two missions remain later this year.