Spacewalking NASA astronauts make repairs outside space station

Astronauts Bob Behnken, Chris Cassidy replacing batteries during 7-hour spacewalk

This photo provided by NASA shows NASA astronaut Chris Cassidy and NASA Flight Engineer Bob Behnken during a spacewalk outside the International Space Station on Friday, June 26, 2020. Cassidy and Behnken, are conducting the first of at least four spacewalks to replace the last bunch of old station batteries. (NASA via AP) (Uncredited)

Two NASA astronauts did some home maintenance Friday on the orbiting laboratory 200 miles above Earth during a seven-hour spacewalk.

Astronauts Bob Behnken and Chris Cassidy ventured out of the International Space Station Friday morning to install batteries outside the station. The new batteries are part of the plan to upgrade the space station’s power systems.

The astronauts began suiting up in the airlock before 6 a.m. ET to go outside the ISS. The pair then exited the station around 7:35 a.m. to begin their work. NASA astronaut Doug Hurley and Russian cosmonaut Ivan Vagner, both flight engineers, helped the spacewalkers don their suits and prepare for the journey into the vacuum of space Friday morning.

Once outside, the astronauts began work on one of two power channels on the far starboard truss of the station. They will remove three existing nickel-hydrogen batteries and replace them with two new lithium-ion batteries. They will also be installing an adapter plate to complete the circuit to the new batteries and relocating the nickel-hydrogen batteries, according to NASA.

Since Halloween in 2000, astronauts have continuously lived on the ISS. This year will mark the 20th anniversary of humans living and working in orbit.

The battery replacements on the ISS began two years ago.

As he stepped out of the ISS, Cassidy lost a small mirror on his spacesuit adding to the millions of pieces of junk orbiting the Earth.

Spacewalking astronauts wear a wrist mirror on each sleeve to get better views while working. The mirror is just 5 inches by 3 inches, and together with its band has a mass of barely one-tenth of a pound.

Cassidy said the mirror floated away at about a foot per second.

The mirror came loose in darkness. Later, once he was in sunlight, Cassidy inspected his sleeve for clues that might explain how the mirror came off. “There’s no thread damage or anything like that,” he told Mission Control.

Mission Control in Houston said the mirror somehow became detached from Cassidy’s spacesuit. The lost item posed no risk to either the spacewalk or the station, according to NASA.

While millions of pieces of space debris orbit Earth, more than 20,000 items including old rocket parts and busted satellites are big enough to be tracked in order to safeguard the space station and functional satellites.

This will be the seventh spacewalk for both Cassidy and Behnken. Both astronauts have previously conducted six spacewalks on previous missions to the ISS.

[MORE SPACE NEWS: How Crew Dragon compares to flying on space shuttle from the first NASA astronauts to do both | NASA seeks ideas for outer space outhouse offering $20,000 prize for winning loo]

Behnken and Hurley made history last month when they became the first Americans to launch from U.S. soil since 2011, as well as the first to launch on SpaceX’s Crew Dragon spacecraft and Falcon 9 rocket.

Hurley and Behnken are expected to return home in August, NASA officials said.

The next Dragon launch is slated for September.

Meanwhile down on Earth Friday, SpaceX is preparing to launch dozens of satellites that are part of the private companies Starlink installation. That launch is scheduled for 4:18 p.m. from Kennedy Space Center.

The Associated Press contributed to this story.

Subscribe to a weekly newsletter to receive the latest in space news directly to your inbox here.