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Expendable launch system (ELV) An expendable launch system or vehicle (ELV) is a launch vehicle that can be launched only once. After that its components are either destroyed during reentry or discarded in space. ELVs typically consist of several rocket stages that are discarded sequentially as their fuel is exhausted. These stages are designed to burn their fuel and provide thrust during different phases of the launch. Gradual discarding occurs as the ELV ascends, each stage is discarded in sequence as its fuel is depleted. The lower stages are discarded first, allowing the upper stages to continue the ascent. The vehicle gains altitude and speed as it throws stages. Finally, the payload, which is for example satellite or spacecraft, is released into the desired orbit. Nowadays, there is trend to use them less compared to reusable launch vehicles. Companies such as SpaceX are developing rockets that can be reused for multiple launches, reducing costs and environment. However they ...

Solid-propellant rocket A solid-propellant rocket or solid rocket is a rocket with a rocket engine that uses solid propellants (fuel/oxidizer). The earliest rockets were solid-fuel rockets powered by gunpowder. The origin of gunpowder rockets can be attributed to ancient Chinese. All rockets used some type of form of solid or powdered propellant up until the 20th century, after which liquid-propellant rockets offered more efficient and controllable alternatives. Solid rockets are still used today in military worldwide, model rockets, solid rocket boosters and on larger applications for their simplicity and reliability. A simplified diagram of a solid-fuel rocket. source: https://www.grc.nasa.gov/www/k-12/airplane/srockth.html 1. A solid fuel-oxidizer mixture (propellant) is packed into the rocket, with a cylindrical hole in the middle. 2. An igniter combusts the surface of the propellant. 3. The cylindrical hole in the propellant acts as a combustion chamber. 4. The hot exhaust is chok...

Space rocket engine  What is the difference between the jet engine and space rocket engine? They both produce thrust and, as explained by Newton’s Third Law of Motion, eject exhaust gases in an equal and opposite direction. The difference between them is that jet engines get the oxygen to burn fuel directly from the atmosphere and space rockets carry their own oxygen onboard, which allows them to operate in space. You can see main characters on following two Figures 1 and 2.  Figure 1. Turbojet engine; source: Rolls-Royce plc (1996). The Jet Engine. Fifth Edition. Derby, England. Figure 2. A liquid space rocket engine; source: Rolls-Royce plc (1996). The Jet Engine. Fifth Edition. Derby, England.  There are four major components to space rocket: (1) the structural system, or frame, (2) the payload system, (3) the guidance system, and (4) the propulsion system. The propulsion system includes the tanks pumps, propellants, power head and rocket nozzle. The function of t...

What Is Rocket Staging? Staging provides method of increasing an efficiency of a rocket.  Most of the weight of the whole rocket is the weight of its actual propellant. As the propellants are burned off during liftoff, a larger proportion of the weight of the vehicle becomes the nearly empty tank and structure.  In order to lighten the weight of the rocket to achieve an orbital velocity, most rockets discard its own part in a process called staging. A multistage rocket is a launch vehicle that has two or more rocket stages, with each of them containing its own engines and propellants. The lowest stage, or the first stage, ignites and lifts the vehicle at increasing velocity until complete exhaustion of its propellant. At this point the first stage drops off and the second stage ignites and accelerates the vehicle further. Most rockets has 3 stages. credit: NASA At the beginning of the flight, only the bottom or the first stage pushes the whole rocket. After burning out, the st...

 How a simple rocket works? The problem has arisen in the 19th century when experimental balloon flights showed how the Earth's atmosphere thins out with the increasing altitude. It was clear that such devices that create forward and upward forces, such as wings and propellers, would not work in space. Also engines that generate power by burning fuel in the oxygen from the Earth's atmosphere wouldn't work in airless environment.  So what is the solution? Rocket! Rockets generate thrust from the engine. Rockets burn fuel and turn it into hot gas, which is pushed through a nozzle. The force of the gas moving backward pushes the rocket upward or forward. The process is called jet propulsion. Unlike jet engines, rockets don't need air to work and carry everything they need.  A simple rocket consists of a tall cylindrical body constructed from relatively thin metal. The fuel is fitted inside the body of the rocket, while the engines that provide thrust to propel the rocket a...

Where is the edge of space and what is the Karman line? credit: National Geographic Definition where the space starts is not completely clear.  Satellite in space collides with billions of air molecules from the atmosphere. The frequency and intensity of these collisions increases with increasing velocity. At orbital velocity, the energy from those collisions with air molecules produces heat that would melt even metal. It is known as the friction heating effect.  All orbiting satellites must operate in space in order to avoid the frictional heating effect. It is difficult to estimate. Traces of the gases which we are breathing extends beyond 161 km above the Earth's surface. Above this altitude it is safe for satellite to move at orbital speed without the danger of incineration from the frictional heating.  Many other definitions exist where the space really begins.  Generally, it is told that space starts at the point where orbital dynamic forces become more importa...