You would be lying if you say that you haven't dreamt of going into the outer space growing up; free-floating inside a spaceship, punching complicated equations into the computer to get to the far reaches of the universe. Your imaginary spaceship probably had advanced Rockets that could travel at the speed of light, didn't it? Well, Well! For all you space lovers out there, here is a fun science quiz about how these amazing Rockets work. Answer and learn along!
Let's start with Isaac Newton!
Newton's Third Law of Motion states that:
Rockets work on the principle of Newton's third law, which talks about action and reaction. In Rockets, the action is the enormous amount of energy released at a very high speed from the nozzle. The reaction is the thrust, a force generated by the Rocket which moves or propels the Rocket in the opposite direction.
Based on the fuel, Rockets can be separated into two different types - the liquid propellant Rockets and the solid propellant Rockets. The liquid propellant Rockets use fuels like the Liquid Hydrogen, Kerosene, Nitric acid and other volatile chemicals. When two different chemicals are combined to make Rocket fuel they are called Bi-propellants and when three different chemicals are used it is called Tri-propellants.
The most commonly used liquid fuel is the _____________
Liquid Hydrogen is basically hydrogen frozen to a very low temperature of -253℃. They are incredibly difficult to manage but are used because they release massive amounts of energy when they burn. But, to combust in space, Hydrogen needs oxygen and this is where the oxidisers come in. Liquid Oxygen is the most common oxidiser used, obtained by freezing oxygen to -183℃.
Rockets have to be incredibly efficient - they have to be the right size and the right weight. Oxygen and Hydrogen in gaseous form, though light in weight, occupy a lot of space. Therefore, a process called Liquefaction is used to convert the gases into liquids. The process increases the density, thereby allowing the Rockets to store more fuel into smaller spaces. The fuel and the oxidiser are stored in separate chambers. They are then pumped to the combustion chamber at very high pressures. This results in an instantaneous chemical reaction which releases super-heated steam and massive amounts of energy. Then, WE HAVE LIFTOFF!
The liquid rockets can be controlled, stopped and reignited, thus being preferred for the main rocket engine.
When it comes to solid propellants, the oxidiser and the fuel are combined together into a rubbery mix and placed inside a casing made mostly of steel or aluminium. Solid fuels are easier to handle and because they are dense, they occupy lesser space than liquid fuels.
In solid propellant the most used oxidiser is the ____________
Ammonium Perchlorate (NH4ClO4) is the most common solid oxidiser used. It is mixed with Aluminium into a rubber like substance and placed inside a steel casing. When the reaction happens, Ammonium Perchlorate releases oxygen and combines with the Aluminium to release Aluminium oxide, water, hydrogen and nitrogen.
The solid propellants generally cannot be controlled because the fuel and oxidiser are mixed together, igniting all the substance. Most of the solid propellant Rocket engines are reusable. Once they detach from the main engine and fall back to the ground, they are recovered and used again.
Which fuel do you think has the greater efficiency?
The efficiency of Rocket engines is measured by a scientific equation known as the Specific Impulse. It describes the change in momentum per amount of propellant burnt. In general terms, it is the length of time 1 kilogram of Rocket fuel can produce certain amount of thrust. Kind of like fuel efficiency. Liquid propellants have higher Specific Impulse compared to the solid propellants making them the most preferred choice for the main Rocket engines.
The structure of the Rocket is carefully engineered to ensure a smooth launch. While carrying the massive weight of itself, the satellites and the propulsion system combined; it has to also overcome Earth's atmospheric resistance and friction. Sometimes the friction from travelling at such high speeds can cause overheating and burn down the Rocket parts. Therefore, along with being designed in the right shape they also have to be built with the right materials. The Rockets have a cylindrical shape, with the top-most part called the payload fairing or nose-cone which carries the payload. This design helps minimize the atmospheric resistance. The payload fairing is also used to keep the payload system safe from overheating. Once the Rocket is above Earth's atmosphere, where air resistance is low, the nose-cone disintegrates. This is done in order to reduce the mass as much as possible.
There is also yet another mechanisms to reduce a Rocket's weight. In one such design, the Rockets are constructed in parts and each part has its own propulsion system. The parts get discarded one by one when the Rocket reaches certain altitude and is exhausted of fuel.
The process of discarding Rocket parts after they are exhausted is called?
The Rockets are made up of two or three stacked parts (stages), each with their own propulsion system. The first stage or the bottom-most stage is the largest, while the following stages are smaller in size. When a stage is exhausted, the part gets detached from the Rocket and falls to the ground. Then, the next stage is ignited and so on. Many Rockets these days use staging as it helps reduce the weight and helps maintain the acceleration of the vehicle.
There are also Rocket boosters - mostly in the solid fuel propellant version - that are attached to the sides of the first stage Rockets to assist the lift-off. They are also called Stage-0. Once the Boosters detach and fallback to the sea, they are recovered, refilled and are reused for later launches.
What is the minimum speed required to break free from the Earth's gravity?
To escape the clutches of earth's gravity, Rockets have to travel at 11.2 km/s (40,000 km/hr). This is called the escape velocity and is used when scientific probes are sent to the moon and planets in our solar system. If a Rocket is used to launch satellites, then it has to travel at a minimum speed called the Orbital speed - 28,000 Km/hr. Any lesser speed will result in the Rocket falling back to the Earth.
There is a general misconception that rockets maintain a constant speed, which is false. Rockets cannot maintain their speed, it keeps varying based on the air resistance and gravitational pull of the earth.
After a certain time into the launch, the Rocket does not continue going straight up but rather bends at an angle and starts taking a curved path. Then Rockets travel parallel to the Earth's surface.
The bending of the Rocket is achieved by?
When the Rocket is moving straight up, the nozzle producing the thrust is along the center line (black arrow in the picture) of the Rocket and perpendicular to the Earth's gravity. But when the Rocket has to bend, the thrust must bend at an angle called the Gimbaled angle from the center line of the Rocket. To do this, the modern Rockets have controllable nozzles which can be bend either right or left based on the launch path. If the nozzle bends to the right, then the thrust line bends to the left. This creates a torque - a force that causes rotation - making the Rocket turn right.
Gimbaled thrust system ensures that the Rockets also have a guidance system to make sure that it takes the right path and reaches the desired location.
If you would like more Fun Quizzes and Trivia on your favorite topic, write to us at QuizThat.