In March 2009, American Scott Parazynski โ a veteran of five Nasa space shuttle missions, including seven spacewalks, who had racked up more than 23 million miles (37 million km) โ hung up his spacesuit.
โI could have flown once, maybe twice more, but I was keen to stretch my wings as an inventor and entrepreneur,โ says the 63-year-old.
Undeterred, he tried again the following year, and this time succeeded in conquering Earthโs highest mountain above sea level. He reached the top at 4am on May 20, 2009, making him the first person to have flown in space and summited the worldโs highest peak.
Parazynski is a doctor by training โ he was the personal doctor to his hero John Glenn aboard the Discovery shuttle on the then-US senatorโs return to space in 1998.
HIs other adventurous feats include scuba diving deep into a volcanic lake in the Andes mountains of South America, making the first descent into Nicaraguaโs Masaya volcano and visiting Antarctica, where he oversaw the medical care of staff of the US governmentโs Antarctic programme.