Rockets and Launch Vehicles

As I looked at the title of the upcoming ATI course called Rockets and Launch Vehicles, the first question I asked myself was “What is the difference between a rocket and a launch vehicle?  With the help of google, I learned that all launch vehicles are rockets, but not all rockets are launch vehicles.  A […]

As I looked at the title of the upcoming ATI course called Rockets and Launch Vehicles, the first question I asked myself was “What is the difference between a rocket and a launch vehicle?  With the help of google, I learned that all launch vehicles are rockets, but not all rockets are launch vehicles.  A rocket that is powerful enough to send people, satellites, or spacecrafts into space is called a Launch Vehicle.  So, those things you would build and shoot into the sky as a kid are rockets, but they are not launch vehicles.

Rockets, including launch vehicles, take off by burning fuel, which produces a gas byproduct.  That escaping gas produces the force that creates the thrust to power the rocket upward.

Most launch vehicles need multiple stages to produce enough thrust get a spacecraft into space.  These stages usually sit on top of each other, but there also some designs which have the stages parallel to each other; it all depends on the goals of the mission.  The first stage, the stage closest to the ground, is usually the largest.  Its purpose is to lift the spacecraft above the earth’s atmosphere to a height of about 150,000 feet.  The purpose of the second stage, the stage closest to the spacecraft, is to get the spacecraft to achieve orbital velocity.  Usually, when a stage has used up all of its fuel, it serves no additional purpose, so it is jettisoned.

The Space Launch System is a launch vehicle getting a lot of attention and a lot of funding today,  The SLS is the Launch Vehicle which will be used for the NASA Artemis missions which will first return to the moon, and then explore beyond.  The mission of the first Artemis flight, Artemis I, will be to test the SLS launch vehicle using an uncrewed Orion Spacecraft.  This launch will be occurring in March 2022.

If you would like to learn more about rockets and launch vehicles, consider taking the upcoming ATI course Rockets and Launch Vehicles.  You can read more about this course, and register for it here.

And, as always, you learn about other upcoming ATI courses at the ATI homepage www.aticourses.com

Rocket Propulsion Fundamentals

Rocket Propulsion Fundamentals White hot combustion by-products blasted rearward with blinding speed generate the rocket’s propulsive force that that hurls a rocket skyward. Pressure inside the rocket combustion chamber pushes in all directions to form balanced pairs of opposing forces which nullify one another, except where the hole for the exhaust nozzle is placed. Here […]

Rocket Propulsion Fundamentals

White hot combustion by-products blasted rearward with blinding speed generate the rocket’s propulsive force that that hurls a rocket skyward. Pressure inside the rocket combustion chamber pushes in all directions to form balanced pairs of opposing forces which nullify one another, except where the hole for the exhaust nozzle is placed. Here the pressure escapes, causing an unbalanced force at the opposite side of the combustion chamber that pushes the rocket up towards its orbital destination. Both rockets and jets are based on the same principle that causes a toy balloon, carelessly released, to swing in kamikaze spirals around the dining room. A jet sucks its oxygen from the surrounding air, but a rocket carries its own supply of oxidizer on board. This oxidizer can be stored in a separate tank, mixed with the fuel, or chemically embedded in oxygen-rich compounds. A rocket usually has two separate tanks, one containing the fuel, the other containing the oxidizer. The two fluids are pumped or pushed under pressure into a small combustion chamber above the exhaust nozzle, where burning takes place to create a thrust. A solid rocket rocket is like a slender tube filled with gunpowder; the fuel and oxidizer are mixed together in a rubbery cylindrical slug called the grain. Solid propellants are not pumped into a separate combustion chamber. Instead, burning takes place along the entire length of the cylinder. Consequently, the tank walls must be built strong enough to withstand the combustion pressure. Rocket design decisions are dominated by the desire to produce the maximum possible velocity when the propellants are burned. A rocket’s velocity can be increased in two principal ways: by using propellants with a high efficiency and by making the rocket casing and its engines as light as design constraints permit. Unfortunately, efficient propellants tend to have some rather undesirable physical and chemical properties. Liquid oxygen is a good oxidizer, but it will freeze all lubricants and crack most seals. Hydrogen is a good fuel but it can spark devastating explosions. Fluorine is even better but it is so reactive it can even cause metals to burn. Miniaturized components, special fabrication techniques and high strength alloys can all be used to shave excess weight. But there are limits beyond which further weight reductions are impractical. The solution is to use staging techniques whereby a series of progressively smaller rockets are stacked one atop the other. Such a multistage rocket cuts down its own weight as it flies along by discarding empty tanks and heavy engines. However, orbiting even a small payload with a multistage rocket requires an enormous booster. The Saturn moon rocket, for example, outweighed the Apollo capsule it carried into space by a factor of 60 to 1.