Thursday, August 08, 2013

The 5 Most Extreme Atomic Experiments

During the early days of the Atomic Age, it seemed like a healthy dose of nuclear power could make everything better. From 1945 until the late sixties, a bold new world powered by the unlimited cheap energy of the atom seemed perpetually just around the corner.

Image: A is for Atom, Sutherland Productions

Of course, reality fell a bit short of expectations, but it wasn't for a lack of trying. There were some pretty outlandish experiments that went on, often at secret labs in far-away places. In the middle of it all was the U.S. Atomic Energy Commission, now the Department of Energy. They were in charge of the country's nuclear materials, and played a central role in all of the big atomic experiments of the time. Some of the experiments got pretty extreme.

5: Nuclear Fracking
Another Plowshare shot, Sedan, tested to see if a nuclear
 bomb could be used for different kinds of mining
 and earthmoving. Instead, radioactive contamination
spread across the country.
Image: Department of Energy
At the sunset of the atomic age in 1969, the AEC was looking around for new uses for their huge trove of stockpiled nuclear weapons. One idea was to use atomic bombs to mine natural gas. How it works is pretty straightforward. Bury a small bomb deep underground in a natural gas field, and set it off. The explosion would fracture the nearby rocks, shaking loose the methane trapped inside. It was basically taking the traditional method of extracting natural gas, and substituting an atomic bomb for dynamite.

It wasn't the first time the AEC had tried such a swap. They'd been working on the overarching Operation Plowshare since 1961, which tried developing peaceful uses for the atomic bomb. They wanted to see if it could supplant dynamite as the ultimate earthmover. One untried proposal suggested blowing out an artificial harbor using several massive explosions.

The AEC tried extracting natural gas with bombs three times, twice in Colorado and once in New Mexico. Though the bombs did a fine job of shaking loose methane from underground reserves, but the tests were ultimately failures because the extracted gas was too radioactive to use.

4: Nuke the Sky
The United States's first satellite, Explorer 1, discovered an unexpected ring of natural radiation in 1958 about 1,000 kilometers above the Earth. Almost immediately, a scientist in the AEC said lets explode atomic bombs to make an artificial radiation belt of our own.

First came a series of high altitude tests in early August of 1958. Part of Operation Hardtack, the three tests shot bombs as high as 76 kilometers high over the South Atlantic. Later that month, Operation Argus went even higher. Missiles carried small bombs as high as 530 kilometers into the air and created a new layer of radiation around the planet for a few weeks.

The aurora caused by the radiation of Starfish Prime.
Image: Department of Energy
Then they did it again in 1962, only bigger. For the Starfish Prime test, a rocket carried a 1.4 megaton nuclear bomb 400 kilometers above the Pacific Ocean. It detonated with the force of 100 Hiroshima bombs (or about 1000 times the power of the Argus tests). The resulting red, green and blue light show was spectacular, but it created some unexpected effects too. An electro-magnetic pulse, radiated out from the explosion. It knocked out communications and blew out power lines as far off as Hawaii, more than 900 miles away.

The explosion and resulting radiation also created an artificial belt of radiation in space. It ringed the planet and irradiated a many of the low-orbiting satellites of the day. The radiation wreaked havoc with the first communication satellite Telstar, cutting short its operational life to less than one year.

3: Atomic Jetplanes
A B-36 bomber specially modified to test if it could safely carry a nuclear reactor.
Image: U.S. Air Force
In the early days of the Cold War, the Defense Department needed a way to keep planes in the air for as long as possible without refueling, and nuclear energy seemed the solution. The Air Force started designing the plane and the AEC set about designing a nuclear powered jet engine.

In the direct drive nuclear jet engine, compressed
air would flow directly over the hot reactor.
Lightweight, but very dangerous.
Image: The Department of Energy.
They ended coming up with two designs, but both worked using the same principle. Like any jet
engine, air flowing into it would be compressed by turbines. Once it entered the engine's combustion chambers, extreme heat caused the air would expand quickly and be forced out the back, pushing the plane forward. In the nuclear version of the engine, white-hot nuclear rods would take the place of exploding jet fuel .

In this first design, compressed air would flow directly over the hot reactor. This one was was lightweight but left behind a trail of potentially deadly radiation. The second design was heavier, but much safer. It used liquid metal to transfer the heat from the reactor to the air in the engine's combustion chambers, without needing to directly expose the reactor core to the atmosphere directly.

No airplane was built that was actually powered by a nuclear reactor, but they did conduct tests to see if a plane could lift a reactor, and still have enough shielding to protect the crew from radiation. The Air Force modified a B-36 bomber in 1955 to carry a small nuclear reactor in its cargo bay. It wasn't hooked up to anything and didn't power the flight, but it showed that it could be carried and the crew could be protected. The program was canceled in 1962 once rocket technology started to supplant the need for continuously flying airplanes.

2: Atomic Powered Rocket
Schematic of a nuclear powered rocket engine. Image: NASA Archives
Kiwi was the name of one of the nuclear rockets
successfully tested in the 1960s. Image: NASA Archives 
The sky wasn't the limit for atomic propulsion in the '50s and '60s. In the deserts of Nevada, the AEC partnered with NASA to test a series of nuclear rocket engines designed to propel a space ship to Mars. Collectively these tests were called Project Rover, and the engines they built were the Nuclear Engine for Rocket Vehicle Application, or NERVA.

The idea is remarkably simple. First, a white-hot nuclear reactor core would be pumped full of liquid hydrogen. The liquid would heat up, rapidly expand while converting into a gas, and shoot out of the nozzle of the rocket, pushing the spacecraft forward. Hydrogen is the lightest element, so it can be propelled out the back faster than the heaver elements from the exhaust of chemical explosions. The faster gas shoots backwards, the more the rocket thrusts forward.

And it all worked surprisingly well. Tests of the full size engines showed that nuclear rockets had almost double the efficiency of chemical rockets. Altogether, the various designs racked up 17 hours of firing time.

Though the engine worked, the need for it evaporated by the early '70s. It was clear that there weren't going to be Mars missions any time soon, so the program was shut down for good early in 1973.

1: Atomic Bomb Powered Rocket
Plan for a nuclear bomb propelled rocket.
Image: NASA Archives
Project Orion was an even more outlandish concept for atomic powered space exploration than NERVA. The design called for a giant space ship to detonate a hydrogen bomb behind it, and use the blast wave to push the craft forward. Not only that, but to repeat this process every four seconds.

The crazy thing is that using H-bombs to push a spacecraft is basically sound. The ship's design called for a giant "pusher-plate" with huge shock absorbers to catch the thrust of the exploding bomb. If built right, each blast would only incinerate a millimeter of the plate, which could be replaced with a new thick coat of paint every little while. The tricky part was building a gigantic 70-foot wide space craft full of H-bombs and putting that into space.

The design team was headed by maverick physicist Freeman Dyson working at General Atomics in La Jolla California. They boasted they could reach Saturn by 1970. Of course, no one ever got close to building the full sized space ship, but they went as far as contacting the Coca-Cola company to design a mechanism for vending the hydrogen bombs. They also conducted lots of small scale tests using ordinary chemical explosives as a proof of concept.

The program was ultimately canceled in 1964 after the nuclear test-ban treaty prohibited nuclear explosions in the atmosphere and in outer space. 


  1. You're just talkng about US-American nuclear projects.
    But there is more... for example the most used type of wheat in Italy is the result of a nuclear experiment (wheat "creso").

  2. Using nukes to accomplish anything within the Earth's environment doesn't seem like the wisest possible idea.

    Too much radiation pollution is left over. And no amount of radiation is a "safe" amount.

    No nukes is good nukes.

  3. Can't see anything wrong with nuclear space rockets. Or maybe even airplanes. To me its a question of cost, not of risk - the risks are low: extremely unlikely events x reasonable precautions = acceptable cost, such incidents as occur would be trivial comparred to coal mining or automobiles.

  4. NERVA did not emit radiation. It used a heat exchanger to raise the temperature of the hydrogen. Compared to chemical rockets it was not only orders of magnitude more powerful, it was also completely environmentally friendly. 0 radiation, 0 chemical pollutants.

  5. The B-36 mentioned is buried somewhere on Carswell AFB in Ft. Worth, TX. The cockpit was lined with lead to protect the crew. Guys that flew it said that with all the lead, it was one of the quietest cockpits they had ever flown in.

  6. Joe Dead Horse = "And no amount of radiation is a "safe" amount"

    Oh, not so, and appears to be, at low levels, beneficial:

  7. Only dead things have 0 radiation emission.

    1. Depending on how they die, they could be emitting a lot of it.

      For example: