Before NASA figured out how to gently land the Space Shuttle, the return leg of a trip from space was (and, as with the Russian Soyuz, still can be) nearly as harrowing as the rocket launch that started it off. During the Mercury, Gemini and Apollo phases of NASA's history, astronauts would return to Earth by splashing down in the middle of the ocean. Within moments support crew would be on site, ready to assist the astronauts out of their capsule.
The crews that made up these reentry support teams, says space historian Amy Shira Teitel in the video above, were absolutely massive. A fleet of ships, including aircraft carriers, tankers and destroyers, was on hand, ready to welcome the astronauts home. The crews to these ships, says Teitel, could grow to well above 15,000 people. It's yet another example of how absolutely huge of an effort it was to put just a few people into space.