Nuclear energy is experiencing a renaissance on Earth and in space. Whether we're talking about moon bases or space exploration, nuclear energy could be the key to going beyond our current limits.
On August 25, 2012, the lone Voyager 1 space probe crossed the threshold of interstellar space. At the time it was 18 billion kilometers (11 million miles) away from the sun, much farther than all the planets in our solar system.
Voyager 1 was launched in 1977. Almost 50 years later, it is still sending information, penetrating deeper and deeper into space. It can do this because it runs on nuclear energy.
Nuclear power, long a controversial energy source, has seen renewed interest on Earth to fuel our fight against climate change. But behind the scenes, nuclear power has also faced a renaissance in space.
In July, the US National Aeronautics and Space Administration (NASA) and the Defense Advanced Research Projects Agency (DARPA) jointly announced that they plan to launch a nuclear-powered spacecraft in 2025 or 2026. The Agency European Space Agency (ESA), in turn, finances a series of studies on the use of nuclear engines for space exploration. And last year, NASA awarded a contract to Westinghouse to develop a nuclear reactor concept to power a future lunar base.
“There is a lot of interest in nuclear applications for space at the moment,” said Dr Ramy Mesalam, director of the spacecraft engineering program at the University of Leicester. “The deeper we explore our solar system and beyond, the more attractive nuclear energy will become.”
Moon night
One participant in this new boom is Zeno Power, an American startup founded in 2018. A team led by them recently received a $15 million award to develop so-called radioisotope nuclear power systems for use on the surface of the moon. by NASA. These small, lightweight nuclear power systems have a long history of use in space and can potentially use nuclear waste to generate power.
NASA and international partners such as the European Space Agency (ESA) want to have a lunar base operational before the end of the decade. Most likely, this base partly uses nuclear reactors to generate power and heat.
Nuclear power is particularly attractive for use on the Moon because of the harsh conditions on the lunar surface. Darkness is a particular concern for longer duration missions. “The lunar night lasts 14 Earth days,” said Tyler Bernstein, co-founder and CEO of Zeno Power. “There are also permanently shadowed regions, like craters. Generating solar energy is impossible in the dark and temperatures in some places can exceed -200 degrees Celsius.”
Bernstein hopes to have the first reactors ready by 2025.
Nuclear explotion
However, space travel is an inherently risky activity, especially with nuclear materials on board. Rockets destined for space explode periodically, potentially spreading nuclear waste into space or even on Earth. That's a sobering reality facing Professor Dale Thomas of the University of Alabama in Huntsville.
Works on nuclear propulsion propulsion. Instead of powering a rocket through a chemical reaction, we would power it through a nuclear reaction.
Until now we have mainly used nuclear reactions to provide electricity for spacecraft, but researchers like Thomas want to use these reactions to propel them forward.
This has great potential to push us further into space, but it also forces us to review the way we test rocket engines. Typically, these engines are tested on the ground, where they sometimes explode or fail. This gives engineers key information to improve their designs. However, that test and repair model must be adapted to nuclear propulsion.
“Failing a nuclear engine on the test stand is not a good idea,” Thomas told Al Jazeera. “Their failure modes are much more catastrophic than those of chemical propulsion.”
In other words, building a nuclear engine requires researchers to be more cautious and ensure that no failure occurs. This in turn slows development.
A similar situation arises when sending nuclear reactors into space to power spacecraft and lunar bases. Before doing so, they must meet high safety standards and even be prepared to resist explosions. Luckily, we've figured out how to do it. The first nuclear reactor was launched into space in 1965.
“The security aspect is a challenge,” Mesalam said. “This is always at the heart of the design of a nuclear energy system. But the good news is that we have almost 60 years of experience doing this safely.”
Interplanetary species
In the future, spacecraft could be powered by nuclear engines. We would probably propel them into orbit around Earth using chemical engines and then turn on their nuclear propulsion to propel them on missions far beyond our own planet.
“Chemical propulsion can take us off the Earth and even the Moon,” Thomas said. “But when you go to Mars and beyond, you reach its limits. Atomic propulsion will be key to overcoming that barrier.”
Additionally, nuclear propulsion would open up different ways to explore space. Today, flights to places like Mars and the planets beyond are limited by time windows. Space organizations like NASA calculate complex trajectories that launch spacecraft outside the planets' gravity fields to save fuel. If more powerful and higher capacity nuclear engines were available, this would not be such a high priority, giving us more flexibility in launching these ships.
“A Ferrari will go faster than a Volkswagen because it has a more powerful engine,” Thomas said. “That's what nuclear propulsion is versus chemical propulsion.”
However, before we achieve nuclear propulsion, we may need some time. Thomas maintains that these spacecraft probably won't actually take off until 2030.
However, once we have them, they could be a game-changer. “Nuclear power and propulsion will be a huge foundational technology for taking humans to Mars and beyond,” Bernstein said. “It will be key to making humanity an interplanetary species.”
