Watch: Nuclear Missile Tests in Cold War Seen in Newly Declassified Videos

Nato-designated scrag (liquid fueled 3 stage icbm) ballistic missiles during a military parade in Red Square, Moscow, USSR, 1960s. Sovfoto/UIG via Getty Images

Newly declassified videos show never-before-seen footage of nuclear missile tests conducted by the U.S. during the Cold War.

Researchers at Lawrence Livermore National Laboratory released 62 new videos that show tests of atmospheric nuclear testing during the 1950s and 1960s, when the U.S. was entrenched in an ongoing conflict with the Soviet Union.

"We've received a lot of demand for these videos and the public has a right to see this footage," said LLNL nuclear weapon physicist Gregg Spriggs. "Not only are we preserving history, but we're getting much more consistent answers with our calculations.

Nuclear detonations are "tremendously extreme events," says the LLNL. To capture the footage, each test was recorded by at least 50 cameras, some in place to capture different vantage points and some providing backup in case a camera malfunctioned. Some cameras filmed the explosions in slow motion, going through hundreds of feet of film within a couple seconds to capture all the detail. Others captured frames more slowly, to record how mushroom clouds evolved over longer periods of time.

Much of the film has decayed over time, making the restoration a massive project. But researchers say it's important to see the footage to inform future tests.

"It's been 25 years since the last nuclear test, and computer simulations have become our virtual test ground," said Spriggs. "But those simulations are only as good as the data they're based on. Accurate data is what enables us to ensure the stockpile remains safe, secure and effective without having to return to testing."

One declassified video shows the so-called "Harlem event," a major test that took place 13,645 feet above the Christmas Island area of the Pacific Ocean on June 12, 1962. There are two pulses seen in the video as shockwaves form.

Operation Teapot, or the "Turk event" shows a massive fireball that took place 508 feet above the desert floor of the Nevada Test Site on March 7, 1955.

The "Bighorn event" shows a mushroom cloud on June 27, 1962. According to the LLNL, the speed at which the mushroom cloud rises and the height of the cloud can be used to calculate the strength of the explosion.

"These are devastating weapons, and I hope they're never used in war," said Spriggs. "But the stockpile has been an effective deterrent for more than 70 years. My hope is that this project can help to make sure it stays viable into the future."

More videos can be seen on the LLNL's YouTube channel.