CAPE CANAVERAL, Fla. – A pair of Russian spacewalkers breezed through a series of chores outside the International Space Station on Friday, installing a camera and an experimental radio system.

Astronauts Dmitry Kondratyev and Oleg Skripochka set up the radio antenna and routed cable for it, then tossed the cover and cable reel overboard. TV cameras showed the items tumbling harmlessly away.

The radio system is designed to transmit large data files to Russian ground controllers.

The men also retrieved a pair of old science experiments. They worked so quickly the spacewalk ended almost an hour early, taking place on the eve of Japan's first-ever launch of a space station supply ship.

"Guys, thank you very much for excellent work," Russian Mission Control radioed.

Their four crewmates — two Americans, a fellow Russian and an Italian — monitored the 5 1/2-hour spacewalk from inside.

The commander is NASA astronaut Scott Kelly, brother-in-law of wounded Rep. Gabrielle Giffords. She's married to Kelly's identical twin brother, Mark, who's also an astronaut.

Kelly said this week he is keeping abreast of Giffords' improving condition through family phone calls and e-mail messages, and Internet news.