The last time an astronaut in training quit NASA's was in 1968. Robb Kulin is now the first in 50 years to walk out of the prestigious space program.
Thirty-four-year-old Kulin, who joined NASA from Elon Musk's Space X, was one of 12 selected from more than 18,000 applicants in 2017. He was previously an ice driller in Antarctica and worked as a commercial fisherman in Alaska.
NASA said Kulin left for personal reasons, and declined to provide more information due to privacy laws, CBS News reports.
Kulin was undergoing a two-year training program at the Johnson Space Center in Houston before he abruptly resigned. You can watch his NASA video below on why he decided to be an astronaut.