U.S. Rep. Gabrielle Giffords, D-Ariz., left, speaks with reitred astronaut Lt. Gen. Thomas Stafford prior to the start of a hearing before the House Subcommitte on Space and Aeronautics regarding Safety of Human Spaceflight on Capitol Hill, Wednesday, Dec. 2, 2009, in Washington. Photo Credit: (NASA/Bill Ingalls)

U.S. Congresswoman Gabrielle Giffords, D-AZ, left, shows a childs' drawing while U.S. Congressman Pete Olson, R-TX, looks on at the U.S. House of Representatives' Committee on Science and Technology, Subcommittee on Space and Aeronautics to discuss proposed changes to NASA's exploration program on Wednesday, March 24, 2010, on Capitol Hill in Washington. Photo Credit: (NASA/Carla Cioffi)

NASA Administrator Charles F. Bolden, right, speaks, U.S. Rep. Gabrielle Giffords, D-Ariz., prior to appearing in front of the U.S. House of Representatives Committee on Science and Technology to discuss the President’s FY 2011 budget request, Thursday, Feb. 25, 2010, on Capitol Hill in Washington. Photo Credit: (NASA/Paul E. Alers)

Guest, front row from right, U.S. Senator Bill Nelson (D-FL), Apollo 11 Command Module Pilot Michael Collins, U.S. Congresswoman Gabrielle Giffords (D-AZ), and Apollo 11 Lunar Module Pilot Buzz Aldrin, listen during the Apollo 40th anniversary celebration held at the National Air and Space Museum, Monday, July 20, 2009 in Washington. Photo Credit: (NASA/Bill Ingalls)

Guest, front row from right, U.S. Senator Bill Nelson (D-FL), Apollo 11 Command Module Pilot Michael Collins, U.S. Congresswoman Gabrielle Giffords (D-AZ), and Apollo 11 Lunar Module Pilot Buzz Aldrin, listen during the Apollo 40th anniversary celebration held at the National Air and Space Museum, Monday, July 20, 2009 in Washington. Photo Credit: (NASA/Bill Ingalls)

CAPE CANAVERAL, Fla. -- In the Press Site auditorium at NASA's Kennedy Space Center in Florida, staff for U.S. Congresswoman Gabielle Giffords brief media after the successful launch of space shuttle Endeavour on its STS-134 mission. From left are, Pia Carusone Chief of Staff, U.S. Rep. Gabrielle Giffords Office, Mark Kimble Press Advisor, U.S. Rep. Gabrielle Giffords Office and Ashley Nash-Hahn, New Media Strategist, U.S. Rep. Gabrielle Giffords Office. Giffords was on hand to watch her husband, STS-135 Commander Mark Kelly and his crew liftoff from Launch Pad 39A on Endeavour's final spaceflight. Endeavour lifted off May 16 at 8:56 a.m. EDT. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jim Grossmann

Former President George H.W. Bush paid a visit to NASA's Johnson Space Center to speak with Expedition 46 Commander Scott Kelly and Flight Engineer Tim Kopra and take a tour of the Space Vehicle Mockup Facility. Kelly’s twin brother, Mark Kelly and his wife, former Congresswoman Gabrielle Giffords were also present. Photo Date: February 5, 2016. Location: Building 30 - ISS Flight Control Room. Photographer: Robert Markowitz

CAPE CANAVERAL, Fla. -- In accordance with a Presidential Proclamation, the American Flag in the Launch Complex 39 area of NASA's Kennedy Space Center in Florida flies at half-staff to honor U.S. Rep. Gabrielle Giffords and others who were wounded or killed during a shooting spree in Tucson, Arizona. This flag and all American Flags at U.S. military and government installations across the country and abroad will remain at half-staff until sunset on Jan. 14. Giffords is the wife of NASA astronaut Mark Kelly, who is scheduled to command space shuttle Endeavour's last mission, STS-134, to the International Space Station later this year. Photo credit: NASA/Frankie Martin

CAPE CANAVERAL, Fla. -- In accordance with a Presidential Proclamation, the American Flag in the Launch Complex 39 area of NASA's Kennedy Space Center in Florida flies at half-staff to honor U.S. Rep. Gabrielle Giffords and others who were wounded or killed during a shooting spree in Tucson, Arizona. This flag and all American Flags at U.S. military and government installations across the country and abroad will remain at half-staff until sunset on Jan. 14. Giffords is the wife of NASA astronaut Mark Kelly, who is scheduled to command space shuttle Endeavour's last mission, STS-134, to the International Space Station later this year. Photo credit: NASA/Frankie Martin

CAPE CANAVERAL, Fla. -- In accordance with a Presidential Proclamation, the American Flag in the Launch Complex 39 area of NASA's Kennedy Space Center in Florida flies at half-staff to honor U.S. Rep. Gabrielle Giffords and others who were wounded or killed during a shooting spree in Tucson, Arizona. This flag and all American Flags at U.S. military and government installations across the country and abroad will remain at half-staff until sunset on Jan. 14. Giffords is the wife of NASA astronaut Mark Kelly, who is scheduled to command space shuttle Endeavour's last mission, STS-134, to the International Space Station later this year. Photo credit: NASA/Frankie Martin

JSC2011-E-015245 (4 Feb. 2011) --- NASA astronaut Mark Kelly, STS-134 commander, describes a blue wristband to reporters during a news conference at NASA's Johnson Space Center. The briefing was held to discuss Kelly resuming training as the STS-134 shuttle mission commander. With the exception of some proficiency training, Kelly has been on personal leave since Jan. 8 to care for his wife, congresswoman Gabrielle Giffords, who was critically wounded in a Tucson, Ariz. shooting. The wristband, which has a peace sign, heart and ?Gabby,? was delivered by Giffords? office. Photo credit: NASA or National Aeronautics and Space Administration

JSC2011-E-015244 (4 Feb. 2011) --- NASA astronaut Mark Kelly, STS-134 commander, speaks to reporters during a news conference at NASA's Johnson Space Center. The briefing was held to discuss Kelly resuming training as the STS-134 shuttle mission commander. With the exception of some proficiency training, Kelly has been on personal leave since Jan. 8 to care for his wife, congresswoman Gabrielle Giffords, who was critically wounded in a Tucson, Ariz. shooting. Photo credit: NASA or National Aeronautics and Space Administration

Captain Mark Kelly, commander of the space shuttle Endeavour’s final mission and husband of retired U.S. Representative Gabrielle Giffords, gives the keynote address during a celebration dinner at Ohio State University honoring the 50th anniversary of John Glenn's historic flight aboard Friendship 7 Monday, Feb. 20, 2012, in Columbus, Ohio. Glenn was the first American to orbit Earth. Photo Credit: (NASA/Bill Ingalls)

Captain Mark Kelly, commander of the space shuttle Endeavour’s final mission and husband of retired U.S. Representative Gabrielle Giffords, gives the keynote address during a celebration dinner at Ohio State University honoring the 50th anniversary of John Glenn's historic flight aboard Friendship 7 Monday, Feb. 20, 2012, in Columbus, Ohio. Glenn was the first American to orbit Earth. Photo Credit: (NASA/Bill Ingalls)

Captain Mark Kelly, commander of the space shuttle Endeavour’s final mission and husband of retired U.S. Representative Gabrielle Giffords, gives the keynote address during a celebration dinner at Ohio State University honoring the 50th anniversary of John Glenn's historic flight aboard Friendship 7 Monday, Feb. 20, 2012, in Columbus, Ohio. Glenn was the first American to orbit Earth. Photo Credit: (NASA/Bill Ingalls)

Expedition 26 Commander Scott Kelly wears a blue wrist band that has a peace symbol, a heart and the word "Gabby" to show his love of his sister-in-law U.S. Rep. Gabrielle Giffords as he rest onboard a Russian Search and Rescue helicopter shortly after he and fellow crew members Oleg Skripochka and Alexander Kaleri landed in their Soyuz TMA-01M capsule near the town of Arkalyk, Kazakhstan on Wednesday, March 16, 2011. NASA Astronaut Kelly, Russian Cosmonauts Skripochka and Kaleri are returning from almost six months onboard the International Space Station where they served as members of the Expedition 25 and 26 crews. Photo Credit: (NASA/Bill Ingalls)

The Ohio State University President E. Gordon Gee, left, Apollo 11 Astronaut Neil Armstrong, 2nd from left, Former space shuttle astronaut and former Under Secretary of the Air Force Dr. Ron Sega, and Captain Mark Kelly, commander of the space shuttle Endeavour’s final mission and husband of retired U.S. Representative Gabrielle Giffords, right, talk prior to a reception at Ohio State University honoring the 50th anniversary of John Glenn's historic flight aboard Friendship 7 Monday, Feb. 20, 2012, in Columbus, Ohio. Glenn was the first American to orbit Earth. Photo Credit: (NASA/Bill Ingalls)

JSC2011-E-015243 (4 Feb. 2011) --- NASA astronaut Mark Kelly, STS-134 commander, speaks to reporters during a news conference at NASA's Johnson Space Center. Peggy Whitson, Astronaut Office chief, is seated next to Kelly. The briefing was held to discuss Kelly resuming training as the STS-134 shuttle mission commander. With the exception of some proficiency training, Kelly has been on personal leave since Jan. 8 to care for his wife, congresswoman Gabrielle Giffords, who was critically wounded in a Tucson, Ariz. shooting. Photo credit: NASA or National Aeronautics and Space Administration

JSC2011-E-015242 (4 Feb. 2011) --- NASA astronaut Mark Kelly, STS-134 commander, listens to a reporter?s question during a news conference at NASA's Johnson Space Center. The briefing was held to discuss Kelly resuming training as the STS-134 shuttle mission commander. With the exception of some proficiency training, Kelly has been on personal leave since Jan. 8 to care for his wife, congresswoman Gabrielle Giffords, who was critically wounded in a Tucson, Ariz. shooting. Photo credit: NASA or National Aeronautics and Space Administration

JSC2011-E-015241 (4 Feb. 2011) --- NASA astronaut Mark Kelly, STS-134 commander, listens to a reporter?s question during a news conference at NASA's Johnson Space Center. Seated next to Kelly are (left to right) Nicole Cloutier-Lemasters, public affairs officer; Brent Jett, Flight Crew Operations Directorate chief and Peggy Whitson, Astronaut Office chief. The briefing was held to discuss Kelly resuming training as the STS-134 shuttle mission commander. With the exception of some proficiency training, Kelly has been on personal leave since Jan. 8 to care for his wife, congresswoman Gabrielle Giffords, who was critically wounded in a Tucson, Ariz. shooting. Photo credit: NASA or National Aeronautics and Space Administration

Director of the Hayden Planetarium Neil deGrasse Tyson speaks as host of the Apollo 40th anniversary celebration held at the National Air and Space Museum, Monday, July 20, 2009 in Washington. Photo Credit: (NASA/Bill Ingalls)