NASA has conducted countless missions since its inception in 1958. But did NASA make a decision in 2003 that went too far, creating the first inter-planetary nuclear weapon?

First, lets start with the evidence that makes this incredible story even possible. On October 19th, 2003, an amateur astronomer named Oliver Meeckers took a low-resolution picture of Jupiter, and noted an anomaly on the planet. Just south of the equator lie a massive, black spot – one foretelling that something grim had occurred recently on Jupiter.

Such black spots were not unknown in 2003. Almost a decade prior, a comet named Shoemaker-Levy 9 created a chain of dark black spots on the planet when the comet struck the planet with immense force. The fireballs were so unprecedented, that a similar event targeting Earth would have resulted in an extinction-level event.

But what was the cause of this dark spot? NASA, nor any space administration bothered to comment on what may have happened. It is certainly plausible that a rogue comet, smaller than Shoemaker-Levy 9 struck the planet. This has been documented once, in 2009 when Anthony Wesley of Australia photographed another dark spot on Jupiter. However, NASA released an official press statement on that event.

So why did NASA fail to respond to the impact in 2003? Could it be that they had an incentive to keep mum on the reason behind the massive blemish on the Jovian titan? We would suggest that the answer may be “Yes”.

NASA Loves Nukes

Nuclear energy plays a very critical part of interstellar travel. Unlike the pictures we see of Earth-orbiting satellites and space stations, replete with massive solar arrays, probes to the outer planets cannot rely on solar panels to generate significant amounts of energy in which to run the various scientific probes on spacecraft. Therefore, NASA relies on the Radioisotope thermoelectric generator (“RTG” for short) to supply power for probes. The usage of RTGs is very prolific among deep-space probes, and has been used since the 1970s for notable probes such as Pioneer and Voyager, up through current spacecraft that are still completing their missions such as Cassini and New Horizons.

The Jovian Connection

So how are RTGs connected with Jupiter and a possible nuclear detonation on the planet? The answer may be found almost exactly a month before Mr. Meekers’ picture was taken. On September 21st, NASA decided, in a very odd decision, to send their RTG powered probe named Galileo hurdling into the planet as its final mission.

The reason behind the destruction was mostly sound: NASA worried that a dead probe orbiting Jupiter could eventually contaminate its moons which may harbor life. Scientists believed in 2003, as they do now, that both Europa and Callisto have significant amounts of ice water, and are theorized to have subsurface oceans which may have microbial life.

With this in mind, NASA took no chances, and sent a kill order to the probe, directing the spacecraft to a suicidal dive into Jupiter to prevent contamination. Galileo was almost instantly destroyed during its de-orbit, much in the same way it’s atmospheric probe was crushed when it was released in 1995 to conduct experiments during a descent into the hostile planet.

But did more result from crashing the probe into the planet? Some experts warned that mixing radioactive material and Jupiter may have catastrophic results. Engineer Jacco van der Worp warned, via a radio show, that the RTGs may reach critical mass due to the intense pressure in the lower atmosphere of the planet, and the elements contained within Jupiter’s deep atmosphere.

How It Could Have Happened

Some of the science behind conversion of the spent RTG canisters into an atomic weapon is difficult to reproduce, which has caused some controversy on the issue of turning a peaceful space probe into a weapon of mass destruction.

Documentation on how nuclear weapons were and are built is well known, but very difficult to reproduce. However, the basic idea on how to build a nuclear weapon is as follows (image from Wikipedia):

The “Implosion Assembly Method” was used in the first nuclear weapon utilized over the skies of Hiroshima on August 6th, 1945. This method closely mirrors the possible environment of the RTGs during their descent into Jupiter. Nuclear weapons employ powerful explosives to artificially create incredible pressures, forcing the radioactive material to compress, and attain fission, creating the chain of events leading to a nuclear explosion.

Jupiter naturally creates the incredible pressures needed to compress a radioactive material to achieve fission. After all, that is how our sun shines – immense pressures force reactions in various types of atoms, creating incredible amounts of energy.

One challenge, though, to the argument of plausibility is if the type of material in Galileo’s RTG, U238, could actually create such a weapon. It is absolutely true that U238 can’t create a fissile reaction per se. However, if U238 is enriched, the result is U235, which is considered “Weapons grade” for a nuclear bomb. Could Jupiter provide the needed foundation to enrich U238? We believe so. One of the first discovered methods for creating weapons grade uranium is called “Thermal Diffusion”, which involves the transfer of heat across a thin liquid or gas to accomplish isotope separation, forcing U235 molecules to diffuse towards a hotter surface, while U238 diffuses to a colder surface. We believe that its possible Jupiter created the perfect environment for the transformation of the spent RTG cells into a a nuclear accident waiting to happen.

Turning a Molehill Into a Mountain

One additional criticism of the theory is that if a reaction did indeed occur, causing the radioactive material to explode, it would not create the dark spot seen in the initial picture. This is absolutely true, as the explosive yield would be in the area of 100 kilotons of TNT (or about twice the strength of the bomb used over Hiroshima).

So how could the small reaction spark something much greater? The answer lies in what is underneath the clouds of Jupiter. The gas giant contains high amounts of tritium and deuterium. Both elements are essential parts of the other type of nuclear weapon which results in a fusion reaction. This type of reaction is the basis of what we call a “Hydrogen bomb”, which yields much more energy than a simple fissile bomb.

As per the picture (source: Wikipedia), once the initial reaction is created, the fusion fuel is utilized, creating a much higher yield explosion. The most powerful weapon ever created, the Tsar Bomba used the same type of principle. Given the ample fuel that is available deep within Jupiter, it is plausible that the simple fissile reaction became much, much more.

In fact, such a reaction was the basis of the sequel to the brilliant space opera, 2001: A Space Odyssey, aptly named 2010. But this reaction brings up a great question: why didn’t all of the fuel ignite, creating an even bigger explosion? One that would consume the whole planet?

The answer for this is simple: Jupiter cannot maintain the pressure needed to create fusion on its own. To create the pressures needed to sustain such a reaction requires a much larger mass, to the tune of 10 times the size of Jupiter. These entities are called brown dwarfs, and are only recently understood. Therefore, once the initial reaction of U235 had dissipated, there was little to sustain the reaction.

But What About the Time Delay?

The final barrier to the nuclear explosion is the simple argument of time. The probe crashed into Jupiter on September 21st, and the spot showed up on October 19th – almost a month later. How is that possible?

One important aspect of atmospheric density is that the denser the atmosphere is, the more resistance an object faces when moving in the direction of travel. Therefore, as the Galileo probe hurdled through the Jovian atmosphere, the drag imposed on the craft would naturally slow it down. Scientists do not know if there is a true “Core” to Jupiter, or if it is simply so dense that it becomes as hard as any given rocky bodied object in the solar system.

An expression called “Stokes Law” is the basis for calculating how long it’d take the RTG capsule to reach a depth in Jupiter to reach supercritical mass, which is found in the following formula:

V = (2gr²)(d1-d2)/9µ

where

V = velocity of fall (cm sec-¹),

g = acceleration of gravity (cm sec-²),

r = “equivalent” radius of particle (cm),

dl = density of particle (g cm -³),

d2 = density of medium (g cm-³), and

µ = viscosity of medium (dyne sec cm-²).

Applying the formula to the RTG canisters, we find that it would take just under 1 month to achieve the depth needed for the reaction – the same amount of time between the probe’s demise and the discovery of the Jovian “My stery Explosion”.

But could the RTG canisters survive so long in such a hostile environment? Galileo’s atmospheric probe only survived 53 minutes before it was destroyed at a depth of 160km and 23 times the pressure of Earth’s atmosphere. Pulling data from the Galileo’s RTG containment field, we find that the uranium capsules were coated in iridium, which has a melting point of 4435 degrees Fahrenheit. The uranium capsules were then attached to a boron-graphite membrane that could withstand 6422 degrees Fahrenheit. Keeping the membrane mostly intact is an important part of the theory, as you would need at least 10 kilograms of the 45 contained within the RTG to create a fissile reaction.

Adding it all together, you have a “perfect storm” of sorts – a vehicle that may be able to withstand the temperatures and pressures needed to enrich the uranium and cause detonation, and the time lapse between the probes insertion into Jupiter’s atmosphere, and detonation.

And If You’re Still Not Convinced..

Even after all that has been said, our argument is merely a “What if” scenario of the perfect storm. But could such an event happen again? Space enthusiasts should take note of the following points:

The Jupiter Icy Moons Orbiter – the first nuclear-powered probe (using an actual reactor) was cancelled shortly after the Galileo indecent. NASA has virtually abandoned RTG creation for new probes since the Galileo indecent (the citation being “Cost” to restart the lines needed to create the materials needed for new RTGs) NASA’s substitute for the JIMO mission is using solar panels instead of an RTG – despite the fact that the craft will receive only 4% of the solar energy a similar probe would receive in orbit around Earth The few probes that employed RTGs post-Galileo have have virtually no risk of crash landing into a gas giant, such as the New Horizons mission, which is traveling to Pluto. NASA has significantly discouraged the usage of RTGs in the wake of Galileo. Only New Horizons and MSL have been launched featuring RTGs in the past decade. The one probe currently still utilizing an RTG and orbiting a gas giant, Cassini-Hyugens has been continually extended, preventing decision about its fate. The spacecraft’s initial mission was for approximately 42 months. It was extended for an additional 10 years.

The final point brings the discussion to close. Ultimately, the proof is in the empiricism behind further research into this possible phenomenon. What happens if NASA decides to crash land the Cassini probe into Saturn? What if we find the same mysterious spot on Saturn? Will NASA fail to mention this? In the end, you, the reader, must decide for yourself if NASA did indeed create the most powerful weapon known to man on accident, and spark the first nuclear attack against another planet.