Plutonem: Adding Efficiency to Space Travel Through Fusion Rockets

Since the ancient times, humans have been observant and curious to know why everything around us exists. Looking up into the sky, we see many celestial objects such as stars and planets. In the past few centuries, we have made many jumps in the field of space exploration. Telescopes have been created, the stars have been mapped, people have flown in space and even lived there for over six months. These activities have played a major role in the development of our knowledge about space, yet there is so much more we need to discover.

One thing we need to find is how to make space travel quicker and more efficient. Why making space travel better, out of all the problems mankind faces? Currently, our global population is about 7.6 billion and is exponentially rising. By 2025, in just seven years, the global population will be roughly 8.1 billion. Since our resource availability is going down and our population is rising, the Earth can not sustain such an imbalance. This why we must start looking to live on other planets and in order to do this, shortening the time it takes to reach such planets is a necessity.

As a society, when we think of space in general, we just think “oh yeah, that’s cool” but there are multiple problems with space travel. One major issue is the lack of experience. The last Moon landing was in 1972 and space shuttles have been out of use 2011. We can’t just get up and say “you know what, let’s go to space” as it takes many years of preparation and training. This ties to two other major problems:

• Expenses and Waste: The average cost of launching, not creating, a space shuttle was about $450 billion at the last launch. Many parts of these launches are wasted, such as shuttle rocket boosters or the third and fourth stages of Atlas rockets. These parts are non-reusable, so far. The high cost and space junk created from space travel makes it an inefficient field.
• Danger to Crew: As shown by the previous launch disasters of the Challenger and Colombia shuttles, leaving for and re-entering from space poses as a life-threatening or possibly fatal excursion for crew members.

The root cause of both issues is the fact that today’s rockets use liquid hydrogen fuel cells, which are stored in the shuttle’s tanks. These fuel cells harness energy through a thin membrane when the separated hydrogen and oxygen combine to make water. The usage of liquid hydrogen fuel has many disadvantages such as the emissions of nitrogen dioxide, it is very expensive, it is highly flammable and a struggle to store as a result of its combustibility.

With so many issues and disadvantages of the current method of space travel, many people would give up on figuring out this field. That’s where Plutonem comes in.

Plutonem, Changing Space Travel

As a startup founded by Andrew Benn, Victor Awobegmi and I, Plutonem looks at fusion rockets. The name, Plutonem, Latin for Pluto, symbolizes how we believe that using rockets launched through nuclear fusion can lower the time it takes to get to Pluto from 9 years to 4 years. The symbolic meaning is that we want to extend the limits of human space exploration, similar to how Pluto is at the far reaches of the solar system.

Plutonem is developing a Variable Specific Impulse Magnetoplasma Rocket (VASIMR) that will be powered by nuclear fusion.

Let’s take a look at what nuclear fusion is

Nuclear fusion is a nuclear reaction in which atomic nuclei of low atomic numbers fuse to form a heavier nucleus through the release of energy. An example of this process is the way the Sun gives off heat. It converts hydrogen in to helium and the resulting energy is what we receive as heat.

We are looking into how this same process can be made artificially and used to launch rockets at greater speeds in order to reach greater distances. The prospect of harnessing such large amounts of energy to use as propulsion is nothing easy. It’s like creating a car that can travel twice as fast as every car with a fuel efficiency of 7,000 miles per gallon.

In terms of rockets, fuel efficiency is the same as specific impulse. As fuel efficiency is measured as distance travelled per units of fuel used, specific impulse is measured as the units of thrust per the units of propellant consumed over time. A conventional rocket engine has a specific impulse of 450 seconds. This means that a conventional rocket engine can produce 1 pound of thrust from 1 pound of fuel for 450 seconds.

On the other hand, a fusion rocket drive could have a specific impulse about 300 times greater than conventional rockets. A fusion rocket could have an estimated specific impulse of 135,000 seconds. Also, fusion-powered rockets would use hydrogen as a propellant, not fuel. There are two major improvements a fusion rocket drive shows over chemical rocket engines:

• By using hydrogen as a propellant, a fusion rocket could replenish itself as it travels through space as hydrogen is present in the atmosphere of many planets. In order to refuel itself, the rocket has to dip down into the atmosphere and suck in some hydrogen.
• Since fusion-powered rockets burn their fuel slowly, they can travel father distances in less time. It’s believed that fusion propulsion will allow rapid travel to anywhere in our solar system. Theoretically, this could enable us to have round trips from Earth to Jupiter that last less than two years.

The Variable Specific Impulse Magnetoplasma Rocket (VASIMR)

The VASIMR uses both, plasma and fusion propulsion. There are three basic cells in the VASIMR engine:

• Forward cell — Hydrogen is injected into this cell and is ionized to create plasma.
• Central cell — This cell uses electromagnetic energy and radio waves in order to heat and add energy to the plasma.
• Aft cell — A magnetic nozzle on this cell converts the energy of the plasma into velocity of the jet exhaust (thrust). The magnetic field that is used to expel the plasma protects the spacecraft from the plasma. This is because plasma normally destroys any material it makes contact with because it keeps the plasma from touching the shell of the spacecraft. When exiting the nozzle, the plasma is at the temperature of about 100 million degrees Celsius.

In short, the VASIMR engine creates plasma from hydrogen and then expels that plasma to provide thrust. As previously stated, our mission at Plutonem is to use fusion rockets to make space travel more efficient. On a journey to Mars, you could reach there within 39 days using a fusion-powered rocket. A typical rocket would take 300 days.

Key Note

The way humans are living, the Earth can’t sustain it. We must look to outer space for solutions. Today, conventional rockets use liquid hydrogen fuel, which has many disadvantages such as expenses, wasted resources and danger to crewmates. With these rockets, the distances they travel are not optimized. With Plutonem, by using fusion drives, rockets will travel further distances in much less time. A future with VASIMR rockets will look much more optimal, giving us the ability to speed travel from place to place in our solar system.