Maine astronaut Chris Cassidy along with astronaut Rober Behnken is conducting a spacewalk on the International Space Station on Tuesday, July 21.
NASA says the goal is to finish a 3 and half-year effort to upgrade the station's power system.
Cassidy and Behnken will replace aging nickel-hydrogen batteries with new lithium-ion batteries delivered to the station on a Japanese cargo ship in May.
Cassidy returned to International Space Station for the third time on April 9th.
For a short time, Maine had two NASA astronauts in space. There was a brief overlap of Caribou native Dr. Jessica Meir. Cassidy's crew relieved Meir's team.
Cassidy was born in Salem, MA, but moved to Maine when he was young. He considers York, Maine to be his hometown. He attended York High School before attending the Naval Academy Prep School in Newport, Rhode Island. He graduated in 1989.
Cassidy spent 11 years as a member of the U.S. Navy SEAL Team. He made four six‐month deployments: two to Afghanistan, and two to the Mediterranean.
Cassidy has been working to support about 250 research experiments that aren't possible on Earth, a NASA press release says.
"These pursuits broaden knowledge of Earth, space, physical and biological sciences in ways that benefit everyday lives," NASA said of the mission. "They will help enable long-duration exploration into deep space for future Artemis missions to the Moon and eventually on to Mars."
Cassidy says he remembers himself as "an average Maine kid" who has gotten into a "very interesting career."
His first spaceflight was in 2009, when he became the 500th person to fly in space. His first long-duration mission came in 2013. Prior to this mission, Cassidy has spent 182 days in space, and 31 hours and 14 minutes spacewalking.
