Just a few months earlier, Simon had said to Giffords, "Your job is to inspire people, on a whole variety of issues." Now, she thought, the task at hand couldn't be clearer.

Giffords' toughness and tenacity, said Simon, would be effective tools to keep firearms out of the wrong hands.

"Mark and Gabby are both no-nonsense people," Simon said. "If there's a problem, they get it done. Gabby has always had a true moral compass. And Mark, I mean, he's an astronaut. Astronauts see a problem, and they get it fixed."

No doubt about it, Kelly has a unique resume spanning an eye-popping assortment of jobs from ambulance driver to Merchant Marine cadet to combat naval aviator and, finally, to shuttle and space station astronaut.

He's one of twin brothers (his brother, Scott, is also an astronaut) born to police officers in Orange, New Jersey.

"I think going to the public school kind of made me what I am today," Kelly said during a NASA interview. He filled the time between classes with baseball, swimming, track and football.

Winning a spot at the Merchant Marine Academy, Kelly, now 49, worked on a grain carrier ship as it inched its way across the Pacific. "I thought, 'Boy, this is way too slow,' " he said. "That's when I started thinking about flying airplanes in the Navy."

Years later, after flying the final mission of the space shuttle Endeavour, Kelly said, he realized that his Navy and NASA training had prepared him to help his wife after she was shot.

"I did see, you know, some parallels between what I had to deal with in flying airplanes and flying the space shuttle and what I had to deal with in handling this situation," Kelly told Piers Morgan in 2011. "I would think about these things in the context of, you know, what information do I have ... what kind of decision do I need to make, and do I need to make the decision right now, or can this wait?"

Giffords, 42, grew up in the same city where her life nearly ended on January 8, 2011. The daughter of a Tucson school board member, she attended Scripps College in California and later Cornell, where she studied regional planning. She entered politics in 2000, winning a seat in Arizona's legislature and later in the U.S. House of Representatives.

Kelly and Giffords met during a 2003 work trip to China. They reconnected again a year later after Kelly -- who had been married with two girls -- divorced his first wife. They started a long-distance relationship between Houston and Tucson, and by 2006, Giffords and Kelly were married.

The Tucson shooting didn't change Giffords' personality; it amplified it, Simon said. Giffords has relied on her resilience, Simon said, to recover from wounds that have left her with a brain injury, partial blindness and a paralyzed right arm. She resigned from Congress a year ago to focus on her recovery.

"Her speaking is really coming along," Simon said.

Kelly has spoken about some of the most personal ways that the Tucson attack has changed him. Until the shooting, he said, he hadn't been a "big believer in faith."

"I thought the world just spins, and the clock just ticks, and things happen for no particular reason," Kelly said.

'Willing to put herself out there'

The couple's visit to Newtown earlier this year may have revealed their lobbying strategy: more personal. Less public.

The media were not invited as Kelly and Giffords met privately with parents whose children had been shot to death by a 20-year-old armed with a military-style weapon and two handguns.

The "first couple that we spoke to, the dad took out his cell phone and showed us a picture of his daughter, and I just about lost it, just by looking at the picture," Kelly told ABC News. "It was just very tough, and it brought back a lot of memories about what that was like for us some two years ago."

"I have a lot of regard for her," said Pat Llodra, a Newtown community leader who also met with Kelly and Giffords. "She was harmed, and she was still willing to put herself out there to make a change."