Nuclear Fusion at the Forefront of Deep Space Exploration
By Amrita Ghag
Humanity has made huge advances in space exploration; Yuri Gagarin was the first man in space in 1961, inside the Vostok 1 Capsule. Or, we have Apollo 11 (1969), when Neil Armstrong was the first man on the moon 🌕. It’s incredible to consider that these developments by humanity were made not so long ago! We also can’t forget how many things went wrong in the process. Nothing we were doing was effective. Perhaps we weren’t using the right technology, maybe we needed something more efficient.
Well, I would like to propose the idea of Nuclear Fusion based rockets 🚀. Rockets that would help in deep space exploration, like going to Mars or beyond!
A new space race is emerging, with higher stakes and more ambitious goals than simply returning to Earth’s orbit or the Moon. Fusion rockets will help us reach these goals, here’s why.
Why Nuclear Fusion? ☀️
Nuclear Fusion has always had such immense potential, it’s an abundant energy source from the sun with no consequences at all! However, we humans have never fully learned the ways of Nuclear Fusion, as we haven’t efficiently harnessed it yet.
The reason for this is because Fusion occurs when the atoms are heated to an extremely high temperature 🔥, and then they form Plasma. — Plasma is an extremely hot substance that makes up the Sun and is also the main ingredient for Nuclear Fusion to occur. Under all this heat, the nuclei create energy and fuse to create Nuclear Fusion. But, nuclei also have to be under small spaces to compact, this is one of the many reasons we haven’t harnessed Nuclear Fusion on Earth yet.
Before we start sending rockets into space, we need to efficiently harness Nuclear Fusion on Earth. But, I’m not going to get into that side of Fusion, but instead going to be talking about the future of Fusion… why we need to start implementing Fusion based rockets 🚀!
A Deep Dive into our Current Rocket Ships 🛰️
Space rocket ships are not simple, as they’re our only way of getting out of Earth’s atmosphere. Rocket ships don’t work the same as other flying vehicles, for example, airplanes ✈️, as rockets don’t use wings and propellers, knowing that they would not work in space. For rockets to fly, they generate thrust, using the principle of action and reaction. Exhaust flames are then released by explosive chemicals out of the back of the rocket at a very high speed.
Rockets must also be very delicate, balanced, and controlled to be able to withstand the powerful forces of going from earth’s atmosphere 🌎 to space. To do so, two things happen; first, as the rocket generates thrust using the explosive chemicals, then, fuel and oxidant (chemical that lets fuel to combust) undergo violent chemical reactions. The remaining expanded gases from the explosion are pushed out of the back of the rocket through a nozzle — a specially designed exhaust that directs the hot, high-pressure gas produced during combustion into a stream that travels at hypersonic speeds.
Do you remember Isaac Newton’s third law of motion? Well, it states “that every action has an equal and opposite reaction”. In this case, when the “action” (the force that drives the exhaust out of the rocket to the nozzle), must be balanced by the “equal and opposite reaction” (the thrust pushing the rocket forward — kind of like the rocket itself).
How a Rocket’s Motors Work ⚙️
Modern-day rockets have advanced so much compared to the rockets from 100 years ago today, the way they function is much more complex and efficient 🔥. However, there are two main types of rockets, simple solid rockets, and liquid-fueled rockets.
Simple solid rockets are relatively less complex, as their main purpose is as a booster to provide extra thrust at launch. These rockets follow the same principles of using fuel and oxidant; the pace at which fuel is burned, and ultimately the amount of thrust, can be regulated. Once started, a solid rocket will burn continuously until its fuel is expanded.
Now, the more widespread liquid-fueled rockets are far more complicated. Usually, they use a pair of propellant tanks; one for the fuel and one for the oxidant. These tanks are connected to a combustion chamber using a complex maze of pipes. To deliver the liquid propellant into the chamber, high-speed “turbopumps” use their motor systems to deliver the propellant into the injection system.
Inside the combustion chamber, an ignition mechanism is used to begin combustion — usually, a jet of high-temperature gas or an electric spark 💥 does the trick. However, something that is common is too much fuel/oxidant mixture in the rocket. If there are too many of these chemicals in the combustion chamber, a delayed ignition can generate enough pressure to blow the whole rocket apart!
Interplanetary Travel 🧭
Now, the last thing to mention for our modern-day rocket ships’ deep dive is interplanetary travel; how do rockets go from orbit to deep space 🌌?
Any space mission begins with a launch from the surface of the Earth into a low orbit that is around 124 miles above the majority of the atmosphere. Since friction from Earth’s upper atmosphere is very low and gravity is almost as strong here as it is on the surface, a rocket’s upper stage can maintain a stable and circular path where the forces of gravity and the rocket desire to fly off in a straight line balance each other out.
Many satellites and spacecraft are limited to this low Earth orbit, but those that are meant to leave Earth and explore the rest of the solar system require an additional boost in speed to reach light speed 💨, the speed at which they will never again be attracted to our planet by gravity. Injecting a spacecraft into a Hohmann transfer orbit, an elliptical orbit around the sun, is necessary to get it from one planet to another with the bare minimum of requirements. When a rocket ship reaches its target object, it may enter its final orbit using only gravity, or it may need to employ a rocket push in the opposite direction to produce a stable orbit. Usually, this is done by simply rotating the spacecraft around in space and firing the motor.
So.. what was the point of this deep dive? Well, I’m not sure if it’s obvious to you, but these current rockets have significant drawbacks, such as the potential for explosion and the inability to effectively conduct risk-free deep space exploration. I went in-depth on our current rocket ships, but what about fusion-based rockets?
The US magnetic fusion effort has struggled with a lack of urgency and sporadic financing for this challenging objective for many years, harnessing Nuclear Fusion ☀️. Fusion is hardly ever mentioned when it comes to future energy production in American circles. But, what if there was another, more critical, special, and even more significant application for fusion, what if we applied our knowledge of Nuclear Fusion into space?
A Deep Dive into Fusion Rockets ☀️🚀
Although there have not yet been any successful models of a Fusion Rocket, many companies are still researching into how it will work, how long it may take, and what technologies they would use to pursue this rocket. One famous company that is working to make this possible is NASA.
NASA has been working on two types of Nuclear Fusion systems for space travel; Nuclear Thermal Propulsion & Nuclear Electric Propulsion.
Nuclear Thermal Propulsion Systems ♨️
This system has a high power and average efficiency. It heats a gas, such as hydrogen, in a miniature nuclear fusion reactor, and then accelerates that heated gas via a rocket nozzle to produce thrust. According to NASA engineers, a journey to Mars propelled by nuclear thermal propulsion would be 20%–25% quicker than one using chemical propulsion.
Nuclear thermal propulsion systems can produce 100,000 Newtons of thrust and are more than twice as efficient than chemical propulsion systems, generating twice as much thrust with the same mass of propellant — that’s enough force to get a car 🏎️ from 0–60 mph in about a quarter of a second!
Nuclear Electric Propulsion Systems 💡
Nuclear electric propulsion is the name of the second nuclear-powered rocket technology. The idea is to employ a high-power fusion reactor to generate electricity, which would then power an electrical propulsion system like a Hall thruster. However, nuclear electric systems have not yet been developed. This would be about three times more effective than a nuclear thermal propulsion system in terms of performance. Given the nuclear reactor’s high power output, a large number of separate electric thrusters may be run at once to provide a significant amount of thrust.
For exceptionally long-range missions, nuclear electric systems would be the greatest option because they don’t require direct heat from the sun ☀️(as the plasma in the reactor is heating the atoms), are incredibly efficient, and can produce a reasonable amount of thrust. Nuclear electric rockets are very promising, but a lot of technical issues need to be resolved before they can be used.
The FDR 🚀
Using the two technologies listed above, NASA has been trying to create a Fusion rocket! NASA’s Fusion Driven Rocket (FDR) provides a ground-breaking method of Fusion propulsion where the power source releases its energy directly into the propellant, not requiring conversion to electricity. It uses a solid lithium propellant that doesn’t need a lot of tankage. With little direct contact with the spacecraft, the propellant is heated quickly and propelled to a high exhaust velocity, preventing damage to the rocket and lowering the thermal heat load and radiator bulk.
The FDR is also thought to be feasible with little extrapolation from current technology, at high specific power, at a manageable mass scale, and consequently at a low cost. If achieved, it would not only make it possible for humans to travel between planets in space but also make it a common occurrence.
The research on the magnetically driven implosion of metal foils into a magnetized plasma target to create fusion conditions is the key to realizing all of this.
This work’s logical progression results in a technique that uses metal 🧲shells both as the propellant and to create the Fusion conditions. To compress the target plasma to Fusion conditions, a number of low-mass, magnetically driven metal liners are inductively forced to converge radially and axially and form a thick blanket around it. The metal blanket that surrounds the spaceship absorbs almost all of the radiant, neutron, and particle energy from the plasma, shielding it from the Fusion process and avoiding the requirement for a substantial radiator mass. High thrust is produced at the ideal access point by the expansion of this hot, ionized metal propellant through a magnetically insulated nozzle. Thus, the energy produced by the Fusion process ☀️ is used very effectively!
So… I’ve just given so much information about how Fusion rockets are better than normal rockets; they’re more safe, reliable, cost-friendly, and efficient. This is something I believe in, and I know it will be implemented in the future! Now, although we still haven’t efficiently harnessed Nuclear Fusion on Earth, I still believe that Fusion power will be implemented in space, let’s keep an eye on it because we’ll have to wait and see! 🤩
TL;DR
- Nuclear Fusion is a complex, abundant alternative energy with no consequences
- It is energy from the sun, made with nuclei and plasma!
- We haven’t harnessed this energy efficiently on Earth, but it has tremendous potential in space tech
- Our modern rockets are not efficient, there is always a risk of failure
- With fusion-based rockets, we would be able to go to Mars and back for fun!
- This is because they are ultimately more safe, reliable, cost-friendly, and efficient
- If we accomplished fusion based rockets, we would be able to deep research space!
