John Herschel Glenn Jr., the first American to orbit the Earth and later the oldest to enter space, died on December 8 2016. He was 77 years old when he went back to space in 1998. His first visit was in 1962.
Glenn, an ex-marine and US senator of Ohio, was hospitalised for more than a week and died with his family around. He will be buried at Arlington National Cemetery, Virginia.
"Though he soared deep into space and to the heights of Capitol Hill, his heart never strayed from his steadfast Ohio roots. Godspeed, John Glenn!" Ohio Governor John Kasich said in a statement.
The most interesting thing about Glenn is that NASA agreed to send him again into space at the age of 77. Glenn had lobbied to be sent to space again so that the effects on his aged body could be studied.
He was sent to mission STS-95 on the Space Shuttle Discovery in 1998 as the payload specialist. However, the main purpose of his visit was a study on his aged body.
"For four days, I had 21 different leads—brainwaves and respiration and EKG—21 different body parameters being recorded and sent down to the ground," noted Glenn in 2011, according to Gizmodo.
They tested how absence of gravity affected Glenn's balance and perception, immune system response, bone and muscle density, metabolism, blood flow and sleep. Due to low gravity, muscle and bone deterioration has been noted in astronauts. It also affects the heart and vision.
Fluids in the body, without gravity, move to the head instead of towards the legs. During a recent mission to the International Space Station, astronaut Scott Kelly had as much as 2 litre of fluid that shifted into his head. Kelly was in space for 340 days, one of the longest missions.
Glenn was in space for nine days and orbited the Earth 134 times.
