The Mercury missions proved astronauts could fly in space, but before landing on the moon, we still had plenty to learn. 10 crews flew missions on the two-man Gemini spacecraft and successfully completed many milestones, including the first American spacewalk, the longest human spaceflight mission, and the first connection of two spacecraft together in space. Project Gemini proved that NASA - National Aeronautics and Space Administration was ready to shoot for the moon🚀🌕 | NASA Astronauts

Gemini: launch and booster separation | Britannica