Published: May 19, 2010 5:09 PM EDT

 CAPE CANAVERAL, Fla. (AP) - 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 three new batteries at the International Space Station and even jumped ahead to a fourth.

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. Bowen reported that the cable did not appear to be damaged. As he was tying the cord back so it wouldn't get tangled again, however, he discovered another wire tie that was already there and causing the cable to get hung up. Bowen slid the loose wire tie into a position Mission Control deemed adequate.

Even if it causes the cable to jam again, flight controllers said it could be jerked loose and allow the camera-tilting system to operate properly. Indeed, the tilting function checked out fine in a series of tests. The bulk of the spacewalk involved the batteries.

The work unfolded on the far left side of the space station, with the batteries being replaced in quick succession. They were somewhat cumbersome to handle: 3 feet square and 375 pounds apiece. "It seems to me like you guys are cruising, like you're riding the tsunami," Antonelli said.

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. 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.

In any event, 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. This is Atlantis' final flight as the shuttle program winds down. Only two missions remain, later this year.