Final answer:
Alan Shepard experienced motion sickness and threw up during his historic Mercury-Redstone 3 mission in 1961, becoming the first American to do so in space.
Step-by-step explanation:
The astronaut who got sick and threw up in space soon after the launch was Alan Shepard. Shepard became the first American in space on May 5, 1961, and during his historic flight on the Mercury-Redstone 3 mission named Freedom 7, he experienced motion sickness. This incident occurred less than a month after the Soviet cosmonaut Yuri Gagarin became the first human to orbit Earth, solidifying the competitive nature of the space race. The challenges of experiencing zero gravity have continued to affect astronauts, with NASA even having a modified aircraft, nicknamed the Vomit Comet, to help train astronauts for the sensations of free-fall and weightlessness.