Here’s the challenge. You want to make sure your military satellite is tough enough to withstand the radiation from a nuclear blast.
Here’s the problem. You can’t just put the sat in orbit and nuke it. That’s illegal and dangerous. Plus, you’ll need to study the spacecraft after the test in order to get the results—something hard to do if it’s a cloud of radioactive shrapnel.
So how do you do it? With clever thinking and big, wacky hardware, is how.
The 1967 Outer Space Treaty prohibits the deployment or use of nuclear weapons in outer space, conventionally defined as 62 miles up. Like many such weapons treaties, it came into effect because the signatories feared the consequences of certain kinds of warfare more than than they did the advantages.
Apart from the scary thought of H-bombs passing overhead several times a day, nuclear tests in space demonstrated how nasty atomic-blast side effects could be.
In 1962, the United States detonated a hydrogen bomb in space as part of Operation Dominic, the last American atmospheric nuke test series.
Shortly after the 1958 discovery of the Van Allen radiation belts that surround our planet, Nicholas Christofilos—from what is now Lawrence Livermore National Laboratory—proposed a radical idea.
He said a nuclear weapon detonated hundreds of miles up might create an artificial Van Allen belt orbiting Earth. Its effects might disrupt communications, radar and ballistic missile flights.
Project Argus confirmed Christofilos’ ideas in what some termed “the world’s largest scientific experiment.” Very-high-altitude nuclear detonations could indeed affect Earth’s orbital environment.
Five years later, Operation Fishbowl—the high-altitude part of Operation Dominic—followed up these results with a much larger detonation. After several false starts including a spectacularly awful explosion that heavily contaminated the launch pad, weaponeers successfully lofted and detonated a 1.4-megaton warhead at an altitude of 248 miles.
Nukes in space
The Starfish Prime shot on June 20, 1962 lit up the skies of the entire Pacific Ocean with an artificial aurora, pictured here, that lasted more than seven minutes. It also introduced a new buzzword—Electromagnetic Pulse, or EMP.
The Starfish Prime blast knocked out street lights, blew fuses and triggered burglar alarms throughout the Hawaiian Islands, 800 miles away. Radio communications munged up as far away as California and Australia. And those were just the terrestrial effects.
Just four months before Starfish Prime, the United States put the world’s first civilian communications satellite, Telstar 1, into orbit. A shining symbol of the New Frontier, Telstar became an electronic celebrity, symbolizing the earthly benefits of the Space Age.
The Beatles first came to America via a virtual appearance on The Ed Sullivan Show through Telstar’s communication relay.
But Telstar failed well before the end of its design life. So did several other early satellites belonging to the U.S., Britain and the USSR. Starfish Prime’s electromagnetic pulse was thought to be the chief culprit.
NASA had even greater concerns. The space agency was already deep into planning the Apollo moon shots. A big jump in Earth-orbit radiation from space nuclear tests could jeopardize the moon program and put astronauts’ lives in danger.
For the next two decades, the U.S. and USSR launched nuclear payloads into space—but only reactors and generators for electric power, not weapons. Even these weren’t free from trouble, as the 1978 crash of a Soviet nuclear-powered reconnaissance satellite proved.
But both superpowers remained convinced of the strategic potential of space nukes … and took steps to guard against their effects.
By the 1970s, scientists identified a number of technologies capable of “hardening” satellites from the effects of EMP and radiation. In its March 15, 1982 issue Aviation Week & Space Technology listed “certain metals for satellite exterior surfaces, filtering antenna inputs, fabricating cables from lower atomic-numbered materials … and incorporating special protective circuits in equipment design” among these techniques.
But the proof’s in the pudding and such things needed testing. But how? An underground test couldn’t simulate the vacuum of space and as mentioned before, scientists needed a working satellite to study after the blast.
The Defense Nuclear Agency, the entity in charge of testing the effects of nuclear weapons on military gear, came up with a solution straight out of science fiction.
Rube Goldberg meets The Nuketeers
Engineers constructed a giant, 50-ton vacuum chamber on tank treads, complete with a small workroom and huge hatch. The machine could hold an actual Defense Satellite Communication System bird, suspended inside a simulated space environment.
Workers at the Nevada Test Site drilled a thousand-foot-deep vertical shaft into the desert floor. Usually such shafts were sealed to prevent radioactivity from escaping, as accidentally happened during the Baneberry shot of 1970.
But the Huron King shot required the radiation to run up the shaft and zap the giant mobile vacuum chamber. For a fraction of a second, the satellite would bathe in combat-level radioactivity and EMP. Such rarely-dug shafts are called Vertical Line-of-Sight shafts.
That’s a pretty nifty trick in and of itself, given that immediately after detonation the force of the explosion causes the shaft to collapse, seal itself and entomb the radioactive aftermath of the bomb.
But the collapse causes the ground to subside for hundreds of yards around the shaft, like a man-made sinkhole. What good to encase the satellite in vacuum and fire the bomb if the sinkhole swallows the experiment? Thus the Huron King test chamber, all 50 tons of it, rode upon several tank treads and hooked up to a very long winch cable.
If this all sounds like Rube Goldberg-meets-The Nuketeers, you’re probably right, but sometimes such oddball engineering proves to be the most straightforward solution to a problem.
On June 24, 1980, scientists threw the switch and detonated a 20-kiloton device at the bottom of the Huron King shaft. In a fraction of a second, the surge of radiation and EMP roared up the shaft, bounced off nine-inch-thick sheets of lithium hydride and into the giant vacuum chamber, zapping the turned-on DSCS-3 satellite and its electronics.
With lightening speed, relays slammed shut mechanical traps in the collapsing shaft and guillotine cutters severed the data cables snaking down into the earth. Before the explosion started crumbling the Nevada soil into the depths, a remote-controlled winch dragged the huge vacuum chamber away from the forming sinkhole to safety.
The Huron King test, for all its wacky engineering, successfully addressed its challenges to yield important data on hardening military satellites. Aviation Week reported that “all of the electronics were active and operating during the nuclear event and none suffered any permanent damage from radiation exposure,” suggesting that the techniques already employed protected the spacecraft.
The giant mobile vacuum chamber was such a specialized piece of hardware that it was never used again—and remains near the place it was used. It’s now one of the highlights of the occasional public tours of the Test Site. Such big wacky hardware should endure as a testament to the scary reasons that brought it forth.