(AP) -- The shocking gundown of Rep. Gabrielle Giffords has left NASA reeling: Her astronaut husband was due to rocket away in just three months as perhaps the last space shuttle commander, and her brother-in-law is currently on the International Space Station.
Shuttle commander Mark Kelly rushed to his wife's hospital bedside Saturday as his identical twin brother, Scott, did his best to keep updated on the Arizona shooting through Mission Control, the Internet and the lone phone aboard the space station.
In a statement, Mark Kelly expressed gratitude for the outpouring of support their family has received from Arizona and around the nation.
"Many of you have offered help. There is little that we can do but pray for those who are struggling," he said in the statement.
Mark Kelly also said it is important to remember those who died in the shooting.
"I want to thank everyone for their thoughts and prayers, words of condolences and encouragement for the victims and their families of this horrific event," Scott Kelly tweeted from space.
"My sister-in-law, Gabrielle Giffords is a kind, compassionate, brilliant woman, loved by friends and political adversaries alike - a true patriot. What is going on in our country that such a good person can be the subject of such senseless violence?"
It was the worst news to befall an astronaut in orbit since Christmas 2007, when a space station resident learned of his mother's death in a car-train collision. That astronaut, Daniel Tani, was working in Mission Control in Houston last week, in touch with Scott Kelly and the five other members of the space station crew.
The chief of the astronaut office broke the news to Scott Kelly that a gunman had shot his sister-in-law at a political gathering in Tucson soon after it happened.
NASA officials said Sunday it was premature to speculate on whether Mark Kelly would step down as commander of the April flight of the shuttle Endeavour.
But it was hard to imagine how he could keep up with the grueling training in the next three months, primarily in Houston, and still spend time with his wife of three years, hospitalized in critical condition in Arizona.
Kelly's mission is higher profile than most. Endeavour's final flight will deliver an elaborate physics experiment by a Nobel Prize winner.
For now anyway, it's slated to be the last voyage of the 30-year shuttle program. That fact alone propelled 46-year-old Mark Kelly onto the cover of this month's Air & Space magazine of the Smithsonian Institution; he shares the cover with the first shuttle commander, moonwalker John Young.
In an interview with The Associated Press last fall, Kelly, a Navy officer and three-time shuttle flier, said it was "timing and luck" that snared him one last coveted commander's seat, not his influential wife. She loved sharing his adventure. "She's excited about going to Florida for the launch," he said then.
Until last month, NASA hoped the Kelly brothers would meet in orbit, a PR dream for a space agency often confronted with bad news. But after fuel tank cracks grounded another shuttle mission, Mark Kelly's flight was bumped to April. His brother is to return home in March on a Russian spacecraft, so the reunion in space is off.
As for the rippling effects of Saturday's shooting, there is no precedent for anything like this at NASA. Astronauts have had to bow out of space missions over the decades, but never a commander so close to flight and never for something so brutal.
Mark Kelly's co-pilot, retired Air Force Col. Gregory Johnson, could take over. Or NASA could free up another astronaut with flying-to-the-space-station experience.
"It is premature to speculate on any of this," NASA spokesman James Hartsfield said in an e-mail Sunday. "For now, the focus is on supporting Mark and Scott, and things need to be taken day by day, and all thoughts are with the victims."
NASA Administrator Charles Bolden called Giffords a "a long-term supporter of NASA ... who not only has made lasting contributions to our country, but is a strong advocate for the nation's space program and a member of the NASA family."
Mark Kelly's two teenage daughters from a previous marriage were reportedly with him in Tucson.
The couple met in China in 2003 during a young leaders' forum and married in November 2007 at an organic farm south of Tucson. Giffords, 40, a Democrat, served on the House Science and Technology Committee, and took on NASA affairs while heading the space subcommittee.
She admitted to being nervous at her husband's shuttle launch in 2008. "It's a risky job," she told The Associated Press. "You don't really relax" until touchdown.
Mark Kelly readily accepted his wife's fame. He considered her the bigger star in the family.
Scott Kelly, who like his brother has two daughters, will end his 5 1/2-month mission in March, flying in a Russian Soyuz capsule to Kazakhstan.
On Sunday, Scott Kelly and his crewmates - another American, one Italian and three Russians - kept busy with maintenance work. A busy few weeks are ahead with a spacewalk by two of the Russians and the late January arrival of the first-of-its-kind Japanese cargo ship.
The brothers describe themselves as best friends. Both are Navy captains and former test pilots, and both became astronauts in 1996. They grew up in West Orange, N.J., the sons of police officers.
Neither ever missed the other brother's space launches. Mark was there in October, right at the launch pad, when Scott boarded a Russian Soyuz rocket for the space station.
Both were disappointed when, just weeks later, shuttle fuel tank cracks conspired to keep them apart in space.
Explore further: Twins scheduled to orbit Earth together
Scott Kelly on Twitter: http://bit.ly/dnrukF
Mark Kelly on Twitter: http://bit.ly/a0ZwDw