"Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites."
The study of propulsion systems used in spaceflight, including chemical rockets, electric propulsion, and solar sails.
Aerodynamics: The study of the behavior of gases in motion.
Thermodynamics: The study of the relationships between heat, work, and energy.
Propulsion System Design: The design and integration of propulsion systems with a spacecraft.
Rocket Engines: The study of rockets and their engines, including solid rocket motors and liquid-fueled rockets.
Chemical Propellant: The study of the chemical reactions involved in propelling a spacecraft.
Electric Propulsion: The study of using electric energy to accelerate a spacecraft.
Thrust Vectoring: The control of the direction of the thrust of a rocket engine.
Aerobraking: Using atmospheric drag to slow a spacecraft down during reentry.
Orbital Mechanics: The study of the motion of objects in orbit around a central body.
Trajectory Analysis: The analysis of the trajectory of a spacecraft to determine the path to a specific destination.
Flight Dynamics: The study of the motion of an aircraft or spacecraft in flight.
Materials Science: The study of materials and their properties, including their use in spacecraft construction.
Control Systems: The integration of systems needed to control the movement of a spacecraft.
Test and Evaluation: The analysis and testing of spacecraft propulsion systems to evaluate their performance.
Propulsion System Integration: The integration of all the propulsion system components with the rest of the spacecraft.
Chemical propulsion: This is the most common form of propulsion used in spacecraft. It operates by burning a fuel or oxidizer to create a chemical reaction that produces thrust.
Ion propulsion: This propulsion system is based on the principles of ionization. It uses electric fields to accelerate ions and propel the spacecraft. This type of engine emits less waste than chemical propulsion but requires more energy to operate.
Nuclear propulsion: This type of propulsion relies on nuclear reactions. Nuclear reactions produce much more energy than chemical reactions, and nuclear spacecraft engines can be much smaller than chemical engines.
Solar sails: This system uses the pressure of the sun's light to propel the spacecraft forward. Solar sails require no fuel and can theoretically travel at very high speeds.
Magnetic sails: The magnetic sail propulsion system is a theoretical form of propulsion that uses a magnetic field to propel a spacecraft forward.
Electric propulsion: This is a general term referring to any propulsion system that uses electrical energy to accelerate a propellant. This category includes ion, arcjet, and magnetohydrodynamic (MHD) propulsion.
Plasma propulsion: Plasma propulsion is a type of electric propulsion system in which plasma is used to generate thrust.
Laser propulsion: In laser propulsion, a powerful laser is used to heat a propellant, creating a very rapid expansion of gas that propels the spacecraft forward.
Hybrid propulsion: A propulsion system that combines the features of two or more different types of propulsion systems to achieve better performance.
Anti-matter propulsion: This is a not-so-practical propulsion system that involves using anti-matter as fuel. When anti-matter and matter combine, they annihilate each other and produce a large amount of energy.
Gravity assist: This is a way to use a planet's gravity to alter the trajectory of a spacecraft. By flying close to a planet, the spacecraft can "steal" some of the planet's momentum and use it to change its direction.
Inertial propulsion: This propulsion system requires no external source of energy, but rather relies on the conservation of momentum. The spacecraft relies on the momentum it already has to propel itself forward.
"In-space propulsion exclusively deals with propulsion systems used in the vacuum of space and should not be confused with space launch or atmospheric entry."
"Most satellites have simple reliable chemical thrusters (often monopropellant rockets) or resistojet rockets for orbital station-keeping."
"Russian and antecedant Soviet bloc satellites have used electric propulsion for decades."
"Newer Western geo-orbiting spacecraft are starting to use [electric propulsion] for north-south station-keeping and orbit raising."
"Interplanetary vehicles mostly use chemical rockets as well, although a few have used ion thrusters and Hall-effect thrusters."
"[Electric propulsion] technologies will permit mission designers to plan missions to 'fly anytime, anywhere, and complete a host of science objectives at the destinations' and with greater reliability and safety."
"Expert opinion now holds that a portfolio of propulsion technologies should be developed to provide optimum solutions for a diverse set of missions and destinations."
"Most satellites have simple reliable chemical thrusters [...], but they may have drawbacks related to complexity or efficiency."
"Some satellites use momentum wheels for attitude control."
"Newer Western geo-orbiting spacecraft are starting to use [electric propulsion] for north-south station-keeping."
"Yes, a few interplanetary vehicles have used ion thrusters and Hall-effect thrusters (two different types of electric propulsion)."
"These [hypothetical in-space propulsion] technologies are intended to provide effective exploration of the Solar System."
"[Future propulsion technologies] will permit mission designers to plan missions to 'fly anytime, anywhere, and complete a host of science objectives at the destinations' and with greater reliability and safety."
"The question of which technologies are 'best' for future missions is a difficult one."
"A portfolio of propulsion technologies should be developed to provide optimum solutions for a diverse set of missions and destinations."
"Russian and antecedant Soviet bloc satellites have used electric propulsion for decades."
"Newer Western geo-orbiting spacecraft are starting to use [electric propulsion] for north-south station-keeping and orbit raising."
"Interplanetary vehicles mostly use chemical rockets as well, although a few have used ion thrusters and Hall-effect thrusters."
"[Future propulsion technologies] will permit mission designers to plan missions [...] with greater reliability and safety."