Former astronaut and senator John Glenn, left, sits with Walkersville (Md.) Elementary School students Taylor Huddak, 9 and Emma Kidwell, 10, Thursday, May 6, 2004 at Space Day presented at the National Air and Space Museum-Steven F. Udvar-Hazy Center in Chantilly, Va. The Space Day celebration was to introduce a new class of astronauts, including three educators.
US Senator and astronaut John Glenn with his wife Annie attend the dedication of a new building for the Hollins Communications Research Institute, a new state-of-the-art stuttering research and treatment facility in Roanoke County, Va., Saturday july 11, 1998. Annie was one of the first 100 students in 1973.
Dave Glenn, left, son of Sen. John Glenn, D-Ohio, right, gaves his father a hug as they talk at Kennedy Space Center's Shuttle Landing Facility Oct. 26, 1998 in Cape Canaveral, Fla.
George SheltonAP file
The last remaining four of the original 'Mercury Seven,' from left, Gordon Cooper, Walter Schirra, Scott Carpenter, and John Glenn, stand while the colors are presented during a memorial service for the first American in Space, Alan Shepard, at Johnson Space Center in Houston, Aug 1, 1998.
Sen. John Glenn, left, and Apollo 11 Astronaut Neil Armstrong are seen prior to the start of a dinner at Ohio State University that honored the 50th anniversary of John Glenn's historic flight aboard Friendship 7 Monday, Feb. 20, 2012, in Columbus, Ohio.
Sen. John Glenn talks, via satellite, with the astronauts on the International Space Station, before the start of a roundtable discussion titled "Learning from the Past to Innovate for the Future", Feb. 20, 2012, in Columbus, Ohio.
Jay LaPreteASSOCIATED PRESS
From left, astronaut Buzz Aldrin, Annie Glenn, astronaut and former Ohio Sen. John Glenn, and singer Diana Krall, stand during the opening processional at the Washington National Cathedral in Washington, Sept. 13, 2012, during a national memorial service for the first man to walk on the moon, Neil Armstrong
Sen. John Glenn at his office in Columbus, Ohio, Jan. 25, 2012.
Senator John Glenn gives a eulogy during the funeral of fellow astronaut Scott Carpenter, Nov. 2, 2013, in Boulder, Colo. Carpenter was the second American to orbit the Earth, following John Glenn.
John Glenn is applauded by high ranking Naval Officers shortly after his daughter Lyn Glenn smashed the ceremonial bottle of champagne on the side of the USNS John Glenn during its christening at General Dynamics NASSCO, Feb. 1, 2014, in San Diego, Calif.
Former U.S. senator and astronaut John Glenn speaks to The Associated Press at the Ohio Statehouse, in Columbus, Ohio on May 14, 2015.
On May 29, 2012, President Barack Obama awards the Medal of Freedom to former astronaut John Glenn during a ceremony in the East Room of the White House in Washington.