"Godspeed, John Glenn," NASA wrote in a tweet.
"Today, the people of Ohio remember a devoted public servant who represented his fellow Buckeyes in the U.S. Senate for a quarter century and who fought to keep America a leader in science and technology," President Obama said in a statement. "Our thoughts are with his beloved wife Annie, their children John and Carolyn and the entire Glenn family. The last of America's first astronauts has left us, but propelled by their example we know that our future here on Earth compels us to keep reaching for the heavens. On behalf of a grateful nation, Godspeed, John Glenn."
President-elect Donald Trump shared his condolences on Twitter:
"Today we lost a great pioneer of air and space in John Glenn. He was a hero and inspired generations of future explorers. He will be missed."
Ohio governor John Kasich released a statement about Glenn's death that reads in part:
"John Glenn is, and always will be, Ohio's ultimate hometown hero, and his passing today is an occasion for all of us to grieve. As we bow our heads and share our grief with his beloved wife, Annie, we must also turn to the skies, to salute his remarkable journeys and his long years of service to our state and nation."
Saddened to hear of the passing of a US hero/astronaut/statesman. His courage inspired a generation to explore & serve. Godspeed John Glenn— Mike Pence (@mike_pence) December 8, 2016
A great American, a life of service, an inspiration to us all. Goodbye, John Glenn. Godspeed. pic.twitter.com/duCA8qPYER— Chris Hadfield (@Cmdr_Hadfield) December 8, 2016
John Glenn?s humility and grace made his life achievements even more moving. Our hearts go out to his entire family. pic.twitter.com/GjzAogv6Gy— Nancy Pelosi (@NancyPelosi) December 8, 2016
John Glenn, at the age of 77, became the oldest person to go to space on October 29, 1998. pic.twitter.com/N4lagB5s9S— Good Morning America (@GMA) December 8, 2016
The Corps lost a legend today.— U.S. Marines (@USMC) December 8, 2016
Col. John Glenn? an astronaut, a senator, a Marine? died at the age of 95.
Semper Fi, Sir. pic.twitter.com/xUShqC9JaZ
Glenn was one of the original seven Mercury astronauts. His career included two space flights, 24 years as a U.S. Senator from Ohio, and run for president of the United States.
John Glenn was the first American to orbit Earth during the daring days when we were just beginning to venture beyond the atmosphere. RIP. pic.twitter.com/lcaJOxb0Tc— NASA Earth (@NASAEarth) December 8, 2016
John Glenn was a true American hero, a great public servant and a great man who I was blessed to call my friend.— Maria Shriver (@mariashriver) December 8, 2016