On March 3, 1969, Apollo 9 launched three astronauts on the first crewed test flight of NASA’s lunar module, which astronauts later used to land on the moon. [‘On This Day in Space’ Video Series on Space.com](https://www.space.com/39251-on-this-day-in-space.html)

Astronauts James McDivitt, David Scott and Rusty Schweickart orbited Earth for 10 days. They tested the lunar module’s engines and navigation systems. They also practiced docking and undocking the command module and the lunar module in orbit. (On the fourth day, they took a spacewalk, but it was cut short because Schweickart had a bad case of space sickness.) This mission showed that the lunar module was ready to fly to the moon.