Raphael Thys
NASA Orion Spacecraft rendering — NASA
SpaceX’s Starship will revolutionise space travel and usher in a new era of space exploration, but we have yet to experience the same revolution in space propulsion. We still rely on old, inefficient, and slow chemical rockets to travel from planet to planet, severely hampering our ability to explore outer space. Admittedly, we do have a plethora of cutting-edge rocket technology ready to take over and make these distant worlds much more accessible, but using it would be illegal. Fortunately, the IAEA and the UN are endeavouring to finally unlock these revolutionary rockets. But how exactly?
This all started in 1967, when almost every country in the world signed the Outer Space Treaty. This groundbreaking international legislation ensured governments wouldn’t weaponise space or claim ownership of celestial bodies like the Moon. Without the Outer Space Treaty, projects like NASA’s Apollo and the ISS would never have happened.
But the Outer Space Treaty also banned the use of high-power nuclear devices in space. This was for a variety of reasons, including the fact that high-altitude nukes produce computer-killing EMPs, and the OST wanted to ensure the safety of space launches, given that launches go wrong and if they are carrying high-power nuclear devices, they could spread dangerous radioactive material over large areas. At the time, this ensured the space industry operated in a safe manner and didn’t impact our ability to explore space.
As a result, the only nuclear devices that can be used legally in space are RTGs (Radioisotope Thermoelectric Generators). These devices use a lump of plutonium that self-heats through its radioactivity and turns the heat energy into electricity. RTGs are safe to launch as they don’t contain much nuclear material and have meagre power, meaning they can only power computers, sensors, or weak electric motors. However, they emit far too much radiation to be used on a crewed mission.
But since 1967, engineers have designed nuclear-powered rockets that would turbo-charge our space exploration.
Take, for example, Nuclear Thermal Propulsion (NTP). This uses heat from intense nuclear fission reactions to rapidly heat a gas fuel, such as hydrogen. This increase in pressure is used to fire the gas out of the rocket at insanely high speeds and propel the spacecraft forward. This is far more efficient than chemical rockets, so an NTP-powered spacecraft could reach Mars 25% quicker than current propulsion methods.
There is also Nuclear Electric Propulsion (NEP). This uses a nuclear reactor to power an ion propulsion unit. This uses a high-power electric field to fling atoms out at near-lightspeed and propel the craft forward. We already have low-powered ion drives that use battery power, but by using a nuclear reactor as their power source, we can make them extremely powerful. As such, a NEP-powered spacecraft could reach Mars 60% quicker than current propulsion methods.
As a side note, neither NTP nor NEP can be used to launch a rocket from the Earth’s surface, but they can be used in space. They also all work in theory and should be easy to refine and develop, but we haven’t been able to do so because we need to test them in space.
Yet nuclear technology has the potential to revolutionise more than just propulsion. NASA’s Lunar Base, Elon Musk’s Mars colony, and a slew of plans to drill down and explore the potentially habitable subsurface oceans of Jupiter and Saturn’s moons all require massive amounts of power. Many of these missions can’t rely on solar panels because they are too heavy or there isn’t enough light to make them feasible. So one of the only ways to power these breakthrough missions is with a fully-fledged, space-grade nuclear reactor.
However, even though groups like NASA are developing such reactors, the legality of launching them into space is incredibly dubious. Again, this is because the large amount of mid-to-high enrichment nuclear material they need to work is one of the items prohibited from space launches under the Outer Space Treaty.
Fortunately, the International Atomic Energy Agency (IAEA) and the United Nations (the organisation that enforces the Outer Space Treaty) are taking notice. They know that these technologies could be developed and deployed very quickly and enable era-defining science and exploration. As a result of recent meetings, they are both actively drafting new legislation to overrule the Outer Space Treaty and allow the use of these nuclear technologies in space.
Now, it isn’t as simple as making them legal. Both the IAEA and the UN need to agree on standards to ensure that launches and the use of these technologies are safe. Moreover, they need to ensure they don’t accidentally pave the way for the nuclear militarization of space. So it will take time for this new legislation to come into force.
When it does, however, it will be revolutionary. Nuclear-powered spacecraft could make the journey to Mars fast and safe, making the prospect of establishing a Martian colony far more appealing. We could finally probe the many icy moons on Jupiter and Saturn and see if their deep and vast oceans contain extraterrestrials. The many mysteries of the outer solar systems, such as Planet 9, could be discovered and explored. And it’s all because of some new international law. So, for the sake of our space ambitions, let’s hope the IAEA and UN can pull off this legal readjustment.