BANGOR — Cailan Barton wants to be a lot of things when he grows up, but most of all the 8-year-old wants to be an astronaut.

He came Thursday to Husson University with his father, Frank Barton, 31, and younger brother, Owen, 4, all of Orono, to hear Commander Christopher Cassidy talk about what it’s like to be an astronaut. Both boys were dressed in orange astronaut costumes.

“Both kids are interested in science,” Frank Barton said shortly before Cassidy gave the first of three talks about his work as an astronaut. “And let’s face it, how often do you get to meet a real live astronaut?”

Cassidy, 43, who grew up in York, also spoke to a total of 1,000 middle school students from Greater Bangor who were bused to Husson’s Gracie Theatre. The astronaut showed all three groups footage from his recent six-month stay at the International Space Station and his training in Russia with the two cosmonauts with whom he shared a ride up and back.

The trio returned Sept. 11. Cassidy said that the first U.S. soil he stepped foot on was in Bangor when the plane taking him back to Houston stopped to refuel.

Cassidy said Thursday morning that when he was the students’ ages, he wanted to work for the NBA, not NASA. It wasn’t until he met fellow Navy SEAL and astronaut Bill Shepherd, who was commander of the first space station crew, that Cassidy thought about becoming an astronaut. He joined NASA in 2004.

“I really feel I’m just another Maine guy who’s had some really cool experiences in life,” he said during a break between presentations. “My message is to study hard and work hard, but most importantly do in life what your are passionate about, what you enjoy, because when you do that and do it well, doors open up for you. That’s when opportunity presents itself and you need to take advantage of those opportunities.”

Kelly Mead, a former Bangor grade school teacher and clinical supervision director for education majors at Husson, said that seeing an astronaut who grew up in Maine could help inspire students to realize that “being from here, you can do anything.” Cassidy’s visit also was an opportunity to stress the importance of the science, technology, engineering and math, or STEM, programs in grades five through eight.

Cassidy told the students that he was always good at math and because he played football, basketball and softball, interested in how physics related to sports. Space exploration was not on his mind when he graduated from the U.S. Naval Academy in 1993 after attending York High School.

Today, Cassidy believes that the U.S. and other nations should continue to fund space exploration.

“It’s kind of analogous to back in the Christopher Columbus time frame when people were setting sail from Europe and exploring around the oceans,” he said. “They were pushing the frontiers of where humans are.

“[Space exploration] is essential to the growth of mankind and I honestly believe that eventually — maybe it won’t be in my kids’ lifetimes and it might not even be in my grandkids’ lifetimes — there will be people living on Mars and probably on the moon and, right now, we are setting the groundwork for that to happen,” Cassidy said.

He also predicted that technology used in space soon will be important to human survival on earth. Cassidy said that on the space station, 95 percent of the liquids produced, including urine and sweat, are reclaimed, filtered and reused.

“Water is a necessary component of life and with population growth skyrocketing exponentially, eventually people are really going to push our ability to get fresh water to everyone,” he said. “I think that what we are learning about how to reclaim nearly all of our water will in not too long a time be used to build factories and machines in communities around the world to do exactly that.”

During his NASA career, Cassidy has completed six spacewalks, totaling 31 hours and 14 minutes. He has spent a total of 182 days in space. He said Thursday that the view of Earth from space never gets old.

On March 28, he lifted off for a second trip to the space station from Kazakhstan along with two Russian cosmonauts. The three crew members were the first to complete a trip to the space station in less than six hours. Ordinarily, it takes two days to rendezvous and dock at the space station.

Cassidy said Thursday that the most challenging part of the mission was learning Russian so he could communicate with his fellow space travelers and ground control.

“I was on the space station during the summer months,” he said. “What I really missed were the smells of summer like fresh mown grass and the scent of the ocean.”

Earlier this week, Cassidy visited schools in York and Cumberland counties. On Friday, he will visit a school in Fort Kent.

The Maine astronaut is married and has three children. The family lives in Houston.