Editor's Note: This is part one of a two-part series on Bresnik.

Randy Bresnik has traveled the world and beyond.

The former Marine just completed his latest trip Dec. 14, 2017, when his command of NASA's Expedition 53 successfully touched down to Earth in the frigid landscape of Kazakhstan.

While in space, Bresnik circumnavigated the globe countless times while leading his team on hundreds of science experiments in such areas as biotechnology and microbiology, including studying the effects of microgravity on antibiotic resistance to E. coli. -- far from Fort Knox's Ireland Army Hospital where he was born in 1967.

Bresnik's father had started his career in the Navy as an airplane mechanic working on an aircraft carrier but decided to get out. Later, he came back in the service, this time in the Army.

"My dad was a warrant officer when he came into the Army flying Huey gunships," Bresnik said. "My older sister by three years was born in Fort Rucker [Alabama]. Then it came time for me to be born. It turns out that he had gotten a first battlefield commission in the Vietnam War. So he was now a commissioned officer, and I end up being born in Fort Knox.

"As the family story goes, I was there all of two weeks when they hopped in the car and drove across the country out to southern California," Bresnik continued. "He then went back over to Vietnam for another tour while my mom, sister and I were in California."

Bresnik said his own decision to join the military started during high school.

"Every generation tries to improve on the last, so I joined the Marine Corps of course--"

"Actually, I wasn't aware enough to know such distinction between the services," Bresnik said. "If it was the Air Force, I would have been in the Air Force. If it was the Army, I would have been in the Army. At that point it didn't matter."

Instead, he chose his service based on which one would get him into college.

"Fortunately, the Marine Corps picked me up for a [Naval Reserve Officer Training Corps] scholarship and that allowed me to go to the Citadel in Charleston, South Carolina," Bresnik said. "Thankfully, God was looking out for me because it turns out the Marine Corps was the perfect place for me."

After graduating in May 1989, he attended several other basic and advanced courses before being designated a naval aviator in 1992. From F/A-18 training to three overseas deployments in the Western Pacific, from graduation at the Marine Corps Weapons and Tactics Instructors Course (WTI) and Naval Fighter Weapons School (TOPGUN) in Miramar, California to selection as a test pilot at the Naval Strike Aircraft Test Squadron, Bresnik said each mission along the way prepared him for the next big challenge he would face.

All that culminated in January 2003 when his unit, Marine Aircraft Group Eleven, deployed to Al Jaber Air Base, Kuwait, in support of Operation Southern Watch and Operation Iraqi Freedom.

After a successful tour in Iraq, Bresnik applied to NASA as an astronaut in 2004. He had remembered a good friend of his who was selected in the 2000 class of astronauts.

"I thought, 'Wow! If they'll select him, maybe they'll select me,'" Bresnik said. "The odds are so small. There were guys applying for the 2004 class that were, I thought, more experienced, but you never know what NASA's looking for. You go with who you are what you've done.

"Somehow, NASA decided to select me," Bresnik said. "Here I am 14 years later, still being able to do the same great job."

Throughout his military career and his time with NASA, his father's example has left a permanent mark on Bresnik, whether it was as a helicopter pilot in Vietnam, where he earned a Purple Heart and Bronze Star, or as a pilot and deputy sheriff for 25 years with the L.A. County Sheriff's Department Air Bureau.

"He was a great role model," Bresnik said. Seeing all his life of service in the military and in law enforcement was a great example for me."

His father's comradery with his Army buddies also left a mark on Bresnik.

Growing up, Bresnik remembers how he, his parents and his three sisters would regularly pack their station wagon in southern California and drive to St. Catherines, Ontario, to visit his mother's relatives. Along the way, they would stop somewhere -- practically anywhere.

"Eighty-percent of the time, we were staying with friends of [my father] from the Army; maybe somebody he hadn't seen in 20 years," said Bresnik.

He would marvel at how well they got along.

"I would think, 'How is it they are still friends when they haven't seen each other in 20 years?'" Bresnik said. "Then going to the Citadel, spending over 25 years in the Marine Corps, it's like, you get it.

"When you've trusted your life to another human being, that's a bond you don't lose."