Its in the DNA of we human beings to explore new places. Since ancient times, we have travelled from one place to another, one topology to other, one continent to other, across far fetching seas and highest mountains. We hardly have left any part of this planet untouched. The last century we put our legs on the nearest celestial body to our planet, the Moon, and at present we have been visiting many other planets in the solar system with the help of probes and satellites.
Most of these achievements can be credited to the invention of rocket technology in 1920s which hasn’t changed much in the past 100 years. But now, as our aspirations have grew to travel beyond our solar system to at least our nearest stars, we need to find ways to travel faster and farther. The problem with our traditional fuels is that they does not provide enough energy per unit volume which can make the journey possible. Antimatter, in fact, can be a better alternative to our conventional fuels for space travel. We will be knowing about antimatter in the following section.
What is Antimatter?
We all are familiar with the famous Einstein’s equation, E=mc2, which gives the relation between energy and mass, c being the speed of light. Application of this equation can be seen in nuclear bombs where mass is converted into energy. But the reverse is also true, i.e., when a large amount of energy is confined into a very small volume, which is theoretically what happened at the beginning of this universe, then it produces fundamental particles (electrons, quarks and leptons) but along with these, an equal amount of anti-particles are also produced which have the same mass as the fundamental particles but have opposite charges on them. Matter and antimatter are almost the same. You won’t be able to distinguish between water made up of matter and anti-water made up of antimatter by just seeing, because charge is just a relative term given as per the magnetic behavior between two particles. In an anti-atom, the relative behavior of its anti-electron and anti-proton would be same as the relative behavior of electron and proton in an atom, as in both cases, they will be having opposite charges on them.
How can it solve fuel crisis?
When an antimatter and matter combines, it itself gets annihilated and releases enormous amount of energy. Nuclear energy also works on the same principle but there a very small part of the mass of nuclear fuel gets converted to energy while here, the total fuel is getting converted. It has an energy density of 90 MJ per microgram, highest than any known substance in the universe. An example to give you an idea of the amount of energy packed in antimatter, 100g of antimatter will have the same energy as the total rocket fuel stored in Space-X’s Falcon-9 rocket.
Challenges in building such engines
Antimatter source:- Antimatter is one of the rarest and expensive substances on Earth or in nearby universe. It can be produced in labs but the production is not much economical. Though theoretically, equal number of antimatter and matter should have been present in our universe but space observations shows that there is no nearby source where abundance of antimatter in available, at least not in observable universe. One theory suggests that just after the creation of universe, most of the matter and antimatter collided and got annihilated. Our universe is made out of the matter which left out because of the slight difference in the amount of matter and antimatter that was present initially, which is just 0.00009% of the total matter present initially. Nobody knows the reason for this slight difference.
Trapping antimatter:- Even if you produce antimatter, where are you going to trap it as it gets annihilated as soon as it touches matter. And what we have got is just matter around us.
Directing the produced energy in particular direction to produce thrust:- When antimatter is annihilated, it forms very high energy radiation which is very hard to direct with normal matter.
What can we expect if such a rocket is built
There are few researchers who have come up with ways to counter these challenges. They claim that the exit velocities of the particles(which would produce thrust) of these antimatter rockets is about 1000 times faster than a chemical rocket, moving with about 10% of the speed of light. Till now, Voyager 1 is the fastest human made object which moves with a speed of 15km/sec, which is pretty good, but even with this speed journey to Mars will take months, to outer solar system will take years and to our nearest star, Alpha Centauri will take 30000 years. But this technology being in action, we can reach Mars in weeks, outer solar system in months and to Alpha Centauri in 40 years, which is within human lifetime.
Conclusion
Deep space exploration by humans in future is inevitable, doesn’t matter if it is done through laser technology, nuclear energy or energy harnessed from anti matter. But seeing the advantages of antimatter energy over laser technology and nuclear energy and also seeing the ongoing research in making this work, it seems convincing that it might win this battle of fuels for future rockets and will mark the beginning of a new generation in space exploration.