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  • [Intro] If you've been following the news recently, you  

  • know that getting into space is a tricky businesseven with half a century of experience and plenty  

  • of advanced technology helping us out. But in the early days of spaceflight,  

  • it was a lot harder -- in fact, the paths of  many of those first missions were calculated  

  • entirely by hand, by people like Katherine  Johnson, a mathematician who helped plan the  

  • missions that sent the first Americans into space  and then into orbit, and finally to the Moon.  

  • Johnson was born in White Sulphur SpringsWest Virginia in 1918. An excellent student  

  • who was especially good at math, she was  ready for high school at the age of ten.  

  • But in White Sulphur Springs, African American  students couldn't attend high school, so the  

  • family moved to another part of the state, totown called Institute. There, she and her siblings  

  • continued their education -- though her father  remained in their original hometown to work.  

  • When Johnson started college at 15, one of  her professors recognized her math skills,  

  • and encouraged her to pursue the  subject. The professor created a  

  • course in analytic geometry -- the study of  shapes using coordinates -- just for her.  

  • She became known for asking lots of questions  in class -- not because she didn't understand,  

  • but because she could tell other people  didn't even understand enough of what was  

  • going on to ask what they needed to know. At 18, Johnson graduated college with degrees  

  • in French and Mathematics. She'd originally planned to  

  • earn a graduate degree, too, but when  her husband was diagnosed with cancer,  

  • she took up teaching to support her family. Later, at a family gathering, a relative  

  • mentioned that the National Advisory Committee  for Aeronautics, or NACA -- the organization  

  • that would later become NASA -- was looking  specifically for African-American women  

  • to act ascomputers.” NACA needed these  skills to check engineers' calculations in  

  • the Guidance and Navigation Department. Her work at NACA started in 1953 as one of  

  • these so-calledcomputers in skirts,”  reading data from the black boxes of  

  • airplanes and making calculations based on  that data, to learn how the flight went.  

  • But she still had a lot of questions  -- how did these calculations work,  

  • and why were they so important? She started going to the researchers' meetings  

  • to find some answers. Some people protested  at first, since women weren't usually invited,  

  • but Johnson pointed out that there was no  rule against it, and was allowed to stay.  

  • When the all-male Flight Mechanics Branch -- which  studied how airplanes fly -- needed extra help,  

  • Johnson was selected because of her  knowledge of analytic geometry.  

  • At first, it was meant to be a temporary  transfer, but her skills proved valuable,  

  • and she remained on the team until she  moved to the Spacecraft Control Branch,  

  • which was responsible for designing space  missions and calculating trajectories.  

  • One of those missions was Freedom  7, Alan Shepard's flight that made  

  • him the first American in space. The goal was just to get him to space  

  • and back -- a simple-looking parabolic arc --  but there were lots of factors to consider.  

  • NASA told Johnson where they wanted Shepard  to land, and she worked backward from there.  

  • She had to take into account things like  how high they wanted the capsule to go and  

  • the burnout conditions -- that is, the velocity  and position of the rocket when the fuel ran out  

  • and it entered free fall back to Earth. Shepard's space flight lasted 15 minutes  

  • and 22 seconds and traveled 486  kilometers from its launch point.  

  • And thanks to Johnson's calculations, he splashed  down right on target in the Atlantic Ocean, where  

  • NASA had a helicopter ready to fish him out. By the time NASA was ready to send John Glenn  

  • into orbit, they were using digital  computers to do the calculations.  

  • But even then, they asked Johnson  to confirm the computer's results,  

  • planning how Glenn would go from launch to  three elliptical orbits, then fire rockets  

  • to slow himself down and land in the ocean. Johnson went on to contribute to NASA's famous  

  • Apollo 11 mission, but this time, the planned  end point wasn't the ocean. You guessed it,  

  • the end point was the Moon. This presented a whole new set of  

  • challenges for calculating the trajectorybecause the Moon is a moving target,  

  • the kind you really didn't want to miss. NASA also needed Apollo 11 to land smoothly  

  • on the Moon, away from cliffs and craters. So the rocket had to leave Earth during a specific  

  • launch window, a time when the Moon would be  orbiting Earth right in the rocket's path.  

  • And the trajectory wasn't juststraight shot from the Earth to the Moon,  

  • either. NASA's computers -- and again, Johnson  -- had to factor in the Moon's gravitation and  

  • plan for the rocket's path to be skewed by it. With Johnson's calculations to back them up, the  

  • mission was launched, and on July 20th, 1969, Neil  Armstrong took those first steps on the Moon.  

  • Johnson retired from NASA in 1986, and while  she no longer calculates altitudes, burnout  

  • velocities, or launch windows, she hasn't stopped  counting -- August 26th is her 97th birthday!  

  • Thanks for watching this episode of SciShow  Space, and especially to our patrons on  

  • Patreon who help make this show possibleIf you want to help support this content,  

  • and receive rewards like Google Hangouts with  the hosts and crew, go to patreon.com/scishow  

  • to learn more. And don't forget to go to  youtube.com/scishowspace and subscribe!

[Intro] If you've been following the news recently, you  

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Great Minds: Katherine Johnson, Human Computer

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    joey joey に公開 2021 年 07 月 01 日
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