Powerful rockets allow mining in space
More powerful rockets will allow mining companies to reach asteroids including valuable minerals more easily. The companies particularly focus on 3 types of asteroids.
The countdown hits zero, and 27 awesome rocket engines are activated. The world’s most powerful rocket, Falcon Heavy, lifts off from the launchpad for the very first time, and thousands of spectators cheer ecstatically.
6 February 2018 was an important day in space history, as the huge Falcon Heavy completed its first test flight without any errors. Not since the legendary Saturn V moon rocket flew its last mission in 1973, had the world seen similar lifting power. Falcon Heavy’s engines can lift 63,800 kg into an orbit around Earth – i.e. more than twice as much as its closest competitor, Delta IV Heavy. And Falcon Heavy is just the first of a new generation of heavyweight rockets. With new types of fuel and engines plus stronger materials, the new huge rockets will allow quick tourist space missions, mining on asteroids, and man returning to the Moon.
Rockets defeat gravity
The principle behind rocket propulsion was first described in physicist Isaac Newton’s third law of motion: for every action, there is an equal and opposite reaction. In connection with rockets, the principle is taken advantage of by accelerating gases out through nozzles. When the fast-moving gases leave the nozzle, an opposite force will push the rocket upwards. As soon as the force from the push exceeds gravity, the rocket will lift off from the ground. The rocket begins its journey in a vertical position, but on its way up through the atmosphere, it will travel more and more horizontally. Although the rocket quickly leaves the atmosphere, it is still influenced by Earth’s field of gravity, and as soon as the engines are deactivated, it will start to fall back towards Earth. So, it mu s t obtain a horizontal speed that will neutralise gravity's downward pull. A speed of at least 30,000 km/h is required to remain in orbit around Earth. If the rocket is meant
to go further than an orbit around Earth, such as to Mars, it requires a speed of almost 58,000 km/h. Rockets are designed to obtain as much terminal velocity as possible, as this will allow them tro travel further into space.
Engineers are challenged
Unfortunately for rocket engineers, higher terminal velocity constitutes a challenge that is almost impossible to overcome. According to the classical rocket equation, which describes the way in which all rockets travel, fuel consumption increases exponentially with the rocket's terminal velocity. This means that the faster the rocket must be able to travel, the more of its total weight will be accounted for by fuel, leaving less space for equipment and people. 85 % of the weight on Saturn V’s missions was constituted by fuel, 11 % were engines and hull, whereas the astronauts and their gear only made up 4 %.
As every kg counts, the choice of fuel is one of the first issues settled by engineers, when they develop a new rocket engine. The task of the engine is to convert the fuel in the tanks into fast emission gases. The speed of the emissions determines the terminal velocity of the rocket, so it is important to use fuel with high chemical energy. The most high-energy fuels such as liquid hydrogen are unfortunately highly unstable, increasing the risk of the entire rocket exploding.
So, most booster rockets use a highly refined version of kerosene, which is more reliable, but also less energy-efficient. Several private rocket companies are developing engines which can use a third and brand new fuel in the world of rockets – methane.
Methane's energy density is lower than that of hydrogen, but it is much easier to keep liquid in the tanks. Moreover, methane’s density is lower than that of hydrogen, so the tanks need not be as large. Consequently, engineers save weight, but even with the perfect fuel, the energy is not only used for propulsion. Some of the force from the combustion in the engine is used to pump fuel about the rocket, as the majority of the weight must remain at the tip of the rocket during launch, allowing it to keep its balance. If the centre of gravity is located too far back, the immense forces could quickly make a rocket spin instead of staying on its course.
When the ideal fuel has been identified, engineers must focus on designing the rocket in such a way that it can withstand the most hazardous part of a space mission: its passing