NASA is celebrating 50 years of spacewalks with a new documentary, "Suit Up." The space agency is celebrating the anniversary on June 3.

On June 3, 1965, Ed White became the first American astronaut to leave the relative safety of his spacecraft. Connected to his capsule by a tether – as well as an umbilical supplying oxygen and electricity – the astronaut spent 20 minutes floating freely in space. He moved around using a "zip gun" that propelled him in any desired direction. White wore just one of two optional over-gloves, designed to keep his hands warm during the EVA.

"I had one thermal glove on the one hand, my left hand. I always wanted my right hand to be free to operate that [zip] gun and the camera," White said after returning from the mission.

The unused glove floated out of the hatch after White left the spaceship for his historic spacewalk.

"It looked like it was on a definite trajectory going somewhere. I don't know where it was going. It floated very smartly out of the spacecraft and out into space," White stated during a technical review.

Gemini 4 was the first American space mission during which astronauts carried out scientific experiments. In addition to the first NASA spacewalk, the crew also tested sextants for possible use aboard a future flight to the moon.

The half-hour long film explores the five decades of NASA's extravehicular activities (EVAs). The first person to undertake an EVA was the Russian cosmonaut Alexey Leonov, who embarked on a spacewalk in March 1965.

Photographs and pictures taken of White during the Gemini 4 mission are still popular among the iconic images of the early space age.

White carried mustard seed in the pocket of his spacesuit, as a symbol of Christianity. The symbolism also extended to the faith needed to trust that all systems were working properly. At first, NASA only planned for White to stick his head out the hatch, with another astronaut holding onto him. The decision to carry out a full EVA was made just a week before launch, in response to the spacewalk carried out by Leonov.

"This year we celebrate 50 years since Edward White left his Gemini capsule to become America's first spacewalker. It was only a few years later that we landed humans on the moon," said Charles Bolden, NASA administrator.

During the last 50 years, over 375 spacewalks have been completed by men and women traveling into space. Of these spacewalks, around 260 were carried out by NASA astronauts, and 184 were dedicated to construction and maintenance of the International Space Station (ISS).

Ed White died on January 27, 1967, during preparations for the flight of Apollo 1.

"Suit Up" can be viewed on the NASA YouTube channel.

Here's NASA Astronaut Terry W. Virts tribute video on Twitter to the first U.S. Spacewalk:

This is how I #SuitUp. Celebrating the 50th anniversary of the first U.S. spacewalk by Ed White. pic.twitter.com/GH9CuXPYlI

— Terry W. Virts (@AstroTerry) June 3, 2015