Rocket fuel (rocket propellant)
Rocket fuel, or propellant, is the chemical or gas used to produce thrust in rockets. Types include solid, liquid, hybrid and pressurized gas systems; choice affects performance, handling, and mission roles.
Rocket fuel, often called rocket propellant, is the substance carried aboard a vehicle to produce thrust. Historically and in modern practice most rockets rely on chemical propellants that generate high-speed exhaust by controlled combustion or rapid gas expansion. The general concept of a propellant and its use in a vehicle are described in many technical summaries of rocketry: see propellant and the broader topic of rockets.
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Types of propellant
Propellants appear in several forms. Solid propellants are homogeneous or composite mixes of fuel and oxidizer bound into a grain (solid). Liquid propellants store fuel and oxidizer separately and feed them into a combustion chamber (liquid). Pressurized gases or compressed working fluids are used in simple rockets and demonstrations (gas). There are also hybrid designs that combine a solid fuel with a liquid or gaseous oxidizer.
How they work and key components
Most chemical rockets operate by burning a fuel in the presence of an oxidizer to produce high-pressure hot gases; this process is commonly described as combustion. Typical systems separate the concepts of fuel and oxidizer: the fuel supplies chemical energy while the oxidizer supplies the oxygen needed for combustion in the absence of atmospheric air (oxidizer). Propulsion performance depends on the exhaust velocity, mass flow rate, and chamber conditions.
History and notable examples
Different propellants have been chosen for reasons of thrust, efficiency, storability and cost. The Space Shuttle combined both solids and cryogenic liquids: its two solid rocket boosters used a composite grain containing powdered aluminium and an oxidizer such as ammonium perchlorate, while the main engines burned liquid hydrogen with liquid oxygen. Simple educational devices, like a toy water rocket, use compressed air or other gases to expel water and produce thrust.
Applications, trade-offs and safety
Choice of rocket fuel balances specific impulse (a measure of efficiency), density, handling hazards, temperature requirements and ignition behavior. Cryogenic liquids offer high performance but require insulation and complex plumbing; solid motors are mechanically simple and store well but cannot be throttled or shut down once ignited. Toxicity, flammability and the potential for accidental detonation are important operational considerations for manufacturers and launch operators.
Further reading
- Overview and definitions: propellant
- Rockets and vehicle design: rockets
- Solid propellant chemistry: solid
- Liquid propellant systems: liquid
- Gaseous and pressurized systems: gas
- Combustion fundamentals: combustion
- Oxidizers and reaction partners: oxidizer
- Space Shuttle case study: Space Shuttle
- SRB fuel component: aluminium
- Common oxidizer in composites: ammonium perchlorate
- Cryogenic fuel: liquid hydrogen
- Cryogenic oxidizer: liquid oxygen
- Model rockets and water rockets: water rocket
- Compressed-air propulsion: compressed air
Questions and answers
Q: What is rocket propellant?
A: Rocket propellant is fuel for rockets.
Q: In what forms can rocket propellant be?
A: Rocket propellant can be in the form of solid, liquid or gas.
Q: What are most rockets propelled by?
A: Most rockets are propelled by fire.
Q: What are the two chemicals most chemical rockets use as propellants?
A: The two chemicals most chemical rockets use as propellants are a fuel and an oxidizer.
Q: Are the fuel and oxidizer in chemical rockets sometimes mixed together?
A: Sometimes the fuel and oxidizer in chemical rockets are mixed together.
Q: What were the solid fuel boosters on the Space Shuttle made of?
A: The solid fuel boosters on the Space Shuttle were made of powdered aluminium as fuel and ammonium perchlorate as oxidant.
Q: What were the Space Shuttle main engines fueled by?
A: The Space Shuttle main engines were fueled by liquid hydrogen as fuel and liquid oxygen as oxidant.
Related articles
Author
AlegsaOnline.com Rocket fuel (rocket propellant) Leandro Alegsa
URL: https://en.alegsaonline.com/art/83557
Sources
- science.ksc.nasa.gov : "SOLID ROCKET BOOSTERS"
- science.ksc.nasa.gov : "MAIN PROPULSION SYSTEM"