The Lost Astronaut Mice September 1959. The US Navy strapped 14 mice into a Jupiter rocket. The rocket was destroyed after liftoff. The capsule fell into the Atlantic. The Navy searched. They were never found.
Source
https://www.nasa.gov/history/a-brief-history-of-animals-in-space/Spot an error? Email hello@thefact5.com with a source — we correct visibly.

