On STS-51B, NASA flew 24 rats and 2 squirrel monkeys with Spacelab-3; one monkey showed space sickness while the rats returned with muscle loss

In 1985, Challenger carried rats and monkeys to study microgravity's effects. One monkey experienced space sickness, mirroring human astronaut symptoms. Rats showed notable muscle loss and bone fragility after the mission. This experiment provided early evidence of rapid bodily changes in space. These findings remain relevant for future long-duration space travel.