Spaceship thrusters are essential engines that propel spaceships forward at tremendous speeds, changing their course or making minor corrections to its trajectory.
Thrust is determined by specific impulse, while propellant mass plays an inverse relationship to this equation. Performance specifications of propulsion systems depend on specific impulse, exhaust velocity and power-to-mass ratio as primary measurements of effectiveness.
Gas thrusters
Gas thrusters are spacecraft propulsion systems that utilize nitrogen as their propellant. Nitrogen provides safe and cost-effective propulsion for small satellites; other propellants such as hydrogen or helium produce higher specific impulse but require more complex handling processes.
Propellant choice can influence thruster performance, storage conditions and propellant mass requirements; cost and complexity of propulsion system integration and satellite launch preparations; whether special loading equipment is required at spacecraft integration facilities; theoretical specific impulse value increases with lower atomic/molecular mass propellants.
Gas thrusters are used for intricate tasks such as pointing and attitude control, or docking with other satellites. Unlike larger rocket motors, however, gas thrusters usually require very low forces due to being designed to provide short bursts of acceleration over long periods. To accurately model gas thruster performance using EASY5, we created models of its propellant storage tank, pressure regulator and thruster valve systems in EASY5 before comparing this data against actual test data to determine how they behaved.
Electrostatic thrusters
Electrostatic thrusters use electrostatic forces to accelerate ions toward the spacecraft. This force is independent of propellant mass; rather it depends on electric field strength and direction. Therefore, it is critical that power systems feature low specific mass and thrusters with high conversion efficiency are chosen for spacecraft navigation purposes.
An ion drive works by injecting gas into a primary chamber, where electric and magnetic fields interact with it to generate plasma that is then expelled through a thruster. This interaction produces a highly efficient yet powerful electric propulsion system capable of reaching high exhaust velocities.
Ion drives are capable of neutralizing propellant streams without the need for separate neutralizers, making them suitable for use with various liquids and solids – including those contaminated by chemical contaminants such as cesium or mercury – while also eliminating problems that plagued earlier designs, such as incomplete neutralization of propellant streams or chemical contamination of spacecraft.
Hall thrusters
Hall thrusters use inert gases such as xenon to produce thrust, making them perfect for high-precision stationkeeping when small increments of thrust are needed. They can also be used for other tasks like attitude control and orbit transfer. Their unique feature over chemical rockets lies in being easily adjusted through changes to discharge voltage or propellant mass flow rate.
Thrusters work by injecting neutral xenon gas into a coaxial channel and then ionizing it via collisions with electrons circulating around its exit plane, trapping ions within this ring that are then propelled forward via an electric field between its exit plane and their respective gyroradii.
This thruster boasts an ionization efficiency of 90% and electron current consumption at only 30% of discharge power consumption; making it highly efficient, suitable for applications such as planetary exploration or interplanetary missions.
Field-emission electric propulsion
Field-emission electric propulsion utilizes a high voltage electrostatic field to accelerate charged ions into spacecraft propellant tanks for use as propellant. This technology is currently under development for spacecraft missions.
Thrusters use liquid metal, typically indium, for thrust and their ionization is achieved using high-voltage discharge. Ionization disrupts propellant gas molecules to form Taylor cones on its free surface before being extracted by two or three multi-aperture grid systems that can be tuned for optimal performance and efficiency.
An ion thruster’s energy efficiency depends on both its ionization rate and exhaust speed, so having both set to high can substantially lower overall power requirements, but may not deliver sufficient thrust for certain missions.