On January 21, 1960, a monkey named Miss Sam launched on a Little Joe rocket to help NASA test the launch escape system for its new Mercury spacecraft. [‘On This Day in Space’ Video Series on Space.com]( br This spacecraft would ultimately carry the first American astronauts into space. Miss Sam didn't fly all the way to space; the rocket only reached an altitude of about 9 miles. To test her psychomotor performance during the flight, Miss Sam was trained to pull a lever using a light as a cue. She nailed the test and fared well during the 8.5-minute flight, and the escape system worked according to plan.