While some of the monkeys did come back, others did not survive the experiments. This is because these early space missions were very risky, and the focus was on understanding the effects of space travel on living beings.
Here's a breakdown:
* The US: Sent several monkeys into space, including Ham (1961) who successfully completed his mission and returned to Earth. Others weren't so lucky.
* The Soviet Union: Also sent many monkeys into space, but they were less successful. The mission of Laika, the famous dog, was a one-way trip, sadly.
It's important to remember that these missions, while tragic in some cases, were essential to advancing our understanding of space travel and preparing for human missions. They helped us learn how to keep astronauts safe and pave the way for future space exploration.