It's no small feat to become an astronaut. Applicants traditionally have had to go through a litany of screenings, tests and trainings to earn the coveted title. In 2016 alone, NASA reviewed more than 18,000 applications, with only about 120 called back for interviews. The pool is then whittled down to a select few to undergo a two-year training program [source: Wild].
If history is any indication, left-handedness could increase an applicant's chances of being selected for further review and possible future trips to Mars, or even beyond. Of the 1960's-era Apollo astronauts, one in four was left-handed, a probability uptick of more than 250 percent. A couple of these thoroughly vetted individuals included Buzz Aldrin and Mike Collins, who both made history as part of the Apollo 11 lunar landing crew [source: Sherrod].