Yes, John Glenn knew Katherine Johnson. Katherine Johnson was a brilliant mathematician whose calculations were crucial to the success of NASA’s early space missions, including John Glenn’s historic orbital flight in 1962. Glenn specifically requested that Johnson verify the orbital equations computed by the new electronic computers before his flight. He trusted her calculations more than the machines, which were prone to errors at the time. This trust highlights the significant role Johnson played in the success of the mission and the respect she earned from astronauts like Glenn.