The following photograph was taken by Gemini spacecraft astronauts. The image shows the Agena target vehicle about 45 feet away during an inspection before docking.

Credit: NASA

On this day (March 16) in 1966, astronauts Neil Armstrong and David Scott successfully docked their Gemini VIII spacecraft.

The spacecraft was docked using the Agena target vehicle (seen above), which paved the way for the first-ever linking of two spacecraft together in Earth orbit. The successful accomplishment became a stepping stone to future moon landing missions. And, according to NASA, catching up with already-orbiting spacecraft has been essential to missions involving the International Space Station.

There were issues with the Gemini spacecraft that lead the crew to undock for a half an hour. Eventually the astronauts regained control of the spacecraft by using the reentry control system (RCS). The crew was eventually brought home. The Gemini VIII made an early landing in a secondary landing area in the Pacific.