by Travelling across the universe is no easy job to do, figuring out how we could actually do it is pretty vital. The Universe is expanding continuously ever since the big bang and it might just become inaccessible to us. The existing way of using chemical engines to power our rockets is definitely not the efficient and quick way to do it. They are several propulsion methods proposed, using the solar sails and using the nuclear propulsion engines. The traditional rockets carry the fuel with them which adds up weight to the rocket and thereby slowing it. But the proposed methods below could be ideal for our space missions across the galaxies.
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| Illustration of Nuclear propulsion engines. Source: ESA |
Solar sails
Solar sails are a revolutionary way to propel a space probe around the universe which uses a large reflective sheet that collects the momentum of light from the sun and uses the momentum to thrust the spaceship onward. The photons are key to the working of these solar sails. The photons are little massless balls that act as both a wave and a particle. The photons coming from our sun hit the lightweight panels on the solar sails and transfer momentum to the sail, and it is pushed. When the light wave pushes an object in space, it is defined as radiation pressure.
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| Solar Sails - the future of Space travel |
But the problem with photons is that they don't have any mass which is necessary to have momentum. They generate momentum without any mass. Later research suggested that the momentum of the photon is directly proportional to its frequency. Thus, different light colours produce different momentum as their frequency is entirely different from each other. Even powerful lasers from our planet could be aimed at the solar sails speeding up the craft even more. It is estimated that the solar sails could reach speeds of up to 30,000 kilometres per second (18,600 miles per second).
The direction of this sail could be adjusted by changing the angle of the sail relative to the sun. The traditional way of travelling requires chemical fuels, which adds more weight to the craft, but this doesn't require any fuel and therefore less weight. So the Solar sails can accelerate faster than traditional spacecraft as long as the sun rays keep pushing them. This could be a very useful model for trips across our solar system. Because of lesser weight and a consistent push from the protons, the solar sails could reach speeds that are infeasible to the chemical fuel-powered spacecraft.
Plasma Pulse thrusters
As the name suggests, the plasma pulse thrusters use plasma to generate thrust. Plasma is the fourth state of matter and it is a super hot material made of charged ions. Plasmas can be influenced by the electric and magnetic fields. Plasma thrusters can produce up to 5 times more momentum for every gram of fuel than a regular chemical rocket. The only problem is they are very slow compared to the traditional rocket engines, but they get the job done. They are also a safer mode of transport in cosmic travel as they are no chance of an explosion.
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| CubeSat uses micro-pulsed plasma thrusters |
The plasma is generated by dissipating the Teflon (Polytetra Fluoro-Ethylene). A Teflon block is placed between an anode and a cathode, a spark plug generated electricity. The electric field vaporizes the Teflon to create plasma filled with ions. This electric field actually generates a magnetic field inside the thrusters which pushes the plasma into space. According to Newton's third law of motion, every action has an equal and opposite reaction. So when this engine is connected to the spacecraft, this acts as the proper arrangement for the thrusters and releases the particles into space thereby propelling the spacecraft forward.
The Zond-2 mission of the Soviet Union in 1964 was the first assignment that used the plasma pulse thrusters. Later the plasma thrusters were used for drag correction manoeuvres on several missions of NASA. Scientists all over the globe are testing the systems and components of the plasma pulse thrusters for a more efficient and faster journey across the cosmos. The advancements made in this technology will be useful for future space missions and allow us to start interstellar travel.
Nuclear pulse propulsion
Nuclear pulse propulsion is a fascinating concept which uses nuclear explosion for the rockets' thrust. The usual chemical rocket would take about 6 months to get to Mars, but with the nuclear pulse propulsion technology, we might reach Mars in just 3 months. But there are several risk factors involved in making this idea work out, it has to be safe and compact, and that is not easy to achieve when the engine is at the temperature of 2,430 degrees Celsius (4,406 degrees Fahrenheit).
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| Illustration of Nuclear pulse propeller system. Credits: NASA |
Project Orion was the first mission to use Nuclear pulse propulsion technology in 1958. It would propel in space with the help of blast waves which are created by releasing small nuclear bombs from the rocket. The smaller nuclear bombs would explode in space, creating a plasma explosion that would hit the shock absorbers on the spacecraft and propel the craft forward. It all sounds fascinating, but the idea of using nuclear bombs in space didn't go well with the public. Project Orion was terminated indefinitely, even before its inception. But the failure of the Orion mission is not the end of nuclear pulse propulsion technology.
Nuclear pulse propulsion might be our chance to explore other planets in our solar system and we might want to look into that idea. Instead of using nuclear bombs to propel the craft forward, the nuclear thermal propulsion system could be used. The nuclear fusion reactions happening in the reactor core would release an enormous amount of energy which could provide us with enough thrust to explore the outskirts of the solar system. But the problem with the nuclear propulsion system is that they can only be used in space, so we have to carry the rocket into space with chemical engines. There have been many kinds of research put into this idea, but nothing has gone to space so far.
