When President Bush announced earlier this year a renewed commitment to send astronauts back to the moon and beyond, Christopher Cassidy heard in his words a stirring invitation to both his country and to himself.

Cassidy, a 34-year-old Navy lieutenant commander who grew up in York, sincerely hopes to be the next person to walk on the moon. Unlike many other Americans with similar starry-eyed aspirations, however, Cassidy is in a position to actually realize his dream one day.

He is one of 11 Americans and three Japanese scientists chosen in May as NASA’s first astronaut candidate class in four years. And while Cassidy has a few years of intensive training ahead before he’ll have the chance to go into space, he’s got his gaze locked firmly on the lofty prize.

“There’s such a powerful mystique about going to the moon, to physically stand on its surface and explore it while looking back at the Earth,” said Cassidy, whose astronaut class stopped at the Brunswick Naval Air Station on Thursday after completing survival training in the woods near Rangeley Lake. “It’s still hard to believe that I’ve been given such an incredible opportunity.”

Cassidy, who is married and the father of three children, admits he didn’t grow up with fantasies of flying in space and visiting other planets. Although proficient in math and science while a student and three-season athlete at York High School, where he graduated in 1988, he didn’t get the space bug until he joined the Navy and became a member of the elite warrior force known as the Navy SEAL Teams.

It was there that he heard about a fellow SEAL, Bill Shepherd, the first commander of the International Space Station, who inspired him to follow a similar career path.

“He really was the motivation,” Cassidy said. “When we talked, I asked him what I should do to prepare myself to become an astronaut.”

Shepherd urged Cassidy to continue his education, which at that point consisted of a bachelor’s degree in mathematics from the U.S. Naval Academy. So Cassidy went on to earn a master’s degree in ocean engineering from the Massachusetts Institute of Technology in 2000.

Then came the terrorist attacks of Sept. 11, 2001, and Cassidy was deployed two weeks later to Afghanistan, where he served as Ground Assault Force Commander for international and U.S. combat missions. He served two tours in Afghanistan and earned a Bronze Star for valor after leading a nine-day operation at the Zharwar Kili cave complex, on the border of Afghanistan and Pakistan.

After 11 years as a Navy SEAL, Cassidy knows all about perilous missions and the extraordinary planning necessary to mitigate the risks. That experience and confidence under fire came in handy during the winter of 2003, when the shuttle Columbia exploded just as he was completing the application process for the astronaut candidate program.

“I’ve relied on managed risk and detailed planning my whole career,” he said. “The kind of meticulous planning that the military does in combat missions is what NASA scientists do in space exploration. The risks are obvious – a shuttle can crash just as a car can – but it’s something I feel comfortable with. I’ve never had any doubts about my decision.”

While in western Maine recently, the astronaut class spent four days learning what to do to survive should one of their training missions go awry over a remote wilderness somewhere in the world. They were taught how to find food and water, how to navigate in the dark woods, how to stay warm at night, and how to communicate with rescue teams that can get them out. For Cassidy, whose parents and brother visited with him when he stopped in Brunswick, the wilderness survival school was not nearly as tough as what he’d been through as a Navy SEAL – then again, it wasn’t supposed to be.

“It wasn’t about rigorous training; it was about learning teamwork and how to survive off the land if our training spacecraft were to crash on the plains of Russia, let’s say, during re-entry,” he said. “As a SEAL I spent a lot of time underwater, driving underwater vehicles. I’ve always thought it was neat to be in unknown environments, and I learned a great deal on this trip.”

Back at the Johnson Space Center in Houston, the astronaut candidates will continue training for about a year and a half before they become eligible for a technical-support assignment in the space program. Cassidy’s chance to actually go into space, on the other hand, is still a few years off. There are already about 100 qualified astronauts in line ahead of him.

And while Cassidy is happy to wait his turn, his youngest son, 5-year-old Colin, has not been nearly as patient.

“Right after we moved to Houston, I would come home from training every day and he would ask me if I’d been to the moon that day,” Cassidy said. “I’d always say, ‘Not quite yet.'”