Fifty years ago today, Edward H. White II became the first American astronaut to walk in space.

Here are some things you may not have known about the Gemini 4 mission.

First, White was joined on the mission by James McDivitt, who remained inside the 2-man Gemini capsule.

The mission also included the first attempted space rendezvous, which failed.

Second, before the space walk, the astronauts had problems opening the hatch. McDivitt knew how to fix the problem and was able to successfully open and, more importantly, close the hatch.  During the space walk, a communications problem led White to stay outside the vehicle longer than anticipated and he returned just before the capsule entered darkness.

Third, the mission lasted four days and orbited the earth 66 times, the two men cramped inside the capsule about the size of a compact car.

Our question: Ed White was killed in 1967 in the Apollo 1 fire on the launch pad at Cape Canaveral, Florida. Which other two astronauts were also killed in the accident?

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