Prior to his design, riders had to manually open and close two sets of doors when entering and exiting elevator cars. If anyone forgot to close one of the doors, subsequent elevator riders risked a potentially fatal fall down the elevator shaft.
Prior to his design, riders had to manually open and close two sets of doors when entering and exiting elevator cars. If anyone forgot to close one of the doors, subsequent elevator riders risked a potentially fatal fall down the elevator shaft.
She is also the first astronaut to appear on Star Trek.
She is also the first astronaut to appear on Star Trek.