Deutsch: Mikroantrieb / Español: Micropropulsión / Português: Micropropulsão / Français: Micropropulsion / Italiano: Micropropulsione
Micropropulsion in the space industry refers to a class of propulsion systems designed for small satellites and spacecraft that require low thrust and high precision for manoeuvring, attitude control, and station-keeping. These systems are essential for micro- and nanosatellites, such as CubeSats, enabling them to perform fine adjustments in orbit with minimal power consumption.
Description
Micropropulsion systems are specifically designed for applications where traditional large-scale propulsion systems are impractical due to size, weight, or power constraints. These systems generate very small amounts of thrust, typically in the range of micronewtons (μN) to millinewtons (mN), which is sufficient for precise control and orbital adjustments in small spacecraft.
Micropropulsion technologies are often used for:
- Attitude control: Adjusting the orientation of satellites.
- Orbit maintenance: Correcting drift or maintaining position in low Earth orbit (LEO).
- Formation flying: Coordinating movements of multiple satellites in a constellation.
- End-of-life deorbiting: Ensuring small satellites can safely leave orbit at the end of their mission.
Key types of micropropulsion systems include:
- Cold gas thrusters: Simple and reliable, using compressed gas for short, precise bursts of thrust.
- Electric propulsion (EP): Includes ion thrusters and Hall effect thrusters, offering high efficiency and low fuel consumption.
- Resistojet propulsion: Heats a propellant to create thrust, offering higher efficiency than cold gas systems.
- Electrospray thrusters: Use electrically charged liquid droplets for ultra-precise thrust, ideal for nanosatellites.
- Photon-based propulsion: Uses solar sails to harness the pressure of sunlight, a fuel-free method suitable for long-duration missions.
Special Considerations
- Miniaturisation: Micropropulsion systems must balance performance with size and power constraints to fit within the tight space and mass budgets of small satellites.
- High precision: These systems are often used for scientific missions that require extremely accurate positioning and pointing capabilities.
- Power efficiency: Low power consumption is critical for small spacecraft that have limited solar panel surface area and battery capacity.
Application Areas
- CubeSats and nanosatellites: Essential for extending mission capabilities beyond passive orbit.
- Earth observation satellites: Ensuring precise station-keeping for continuous monitoring of specific areas.
- Constellation satellites: Coordinating multiple satellites for global coverage (e.g., Starlink, Planet Labs).
- Interplanetary missions: Micropropulsion can be used for small probes and deep-space CubeSats, such as Mars Cube One (MarCO).
- Scientific research: Supporting missions that require ultra-fine control for instrument calibration or gravitational wave detection.
Well-Known Examples
- MarCO (Mars Cube One): Demonstrated micropropulsion for deep-space communication support during NASA’s InSight mission to Mars.
- Planet Labs’ Dove satellites: Use micropropulsion for Earth observation and constellation maintenance.
- Starlink satellites (SpaceX): Utilise ion-based micropropulsion systems for orbit adjustments and deorbiting.
- ESA’s LISA Pathfinder: Used micropropulsion to achieve ultra-precise control necessary for gravitational wave detection.
Risks and Challenges
- Limited thrust: Micropropulsion systems are not suitable for rapid manoeuvres or large orbital changes.
- Development complexity: Miniaturising propulsion technology while maintaining reliability and efficiency is technically challenging.
- Cost and scalability: Advanced systems like ion or electrospray thrusters can be expensive for mass production in large constellations.
- Fuel limitations: Many micropropulsion systems have restricted fuel capacity, limiting operational lifespan.
Similar Terms
- Attitude control systems (ACS): Broader category of systems used to control spacecraft orientation.
- Electric propulsion: A family of propulsion technologies that includes micropropulsion variants.
- Cold gas thrusters: Simple propulsion systems used in both micro- and macro-scale applications.
Summary
Micropropulsion is a critical technology for small satellites and precise spacecraft control, enabling orbital adjustments, attitude control, and formation flying. With growing interest in CubeSats and satellite constellations, micropropulsion systems are becoming increasingly important. Though they present unique technical challenges, advancements in electric propulsion and miniaturisation continue to enhance their capabilities and extend the reach of small spacecraft in space exploration and commercial missions.
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