Disposal of Satellites
One of the key aspects of promoting sustainability in the space industry is addressing the issue of space debris. With the increasing number of small satellites being launched, it is important to incorporate deorbiting technologies that allow for safe and controlled disposal of satellites at the end of their operational life. This article reviews some of the innovative small satellite deorbiting technologies that contribute to a cleaner and more sustainable space environment.
Drag Enhancement Devices
Drag enhancement devices, such as drag sails or inflatable balloons, increase the surface area of a satellite, thereby increasing atmospheric drag. This increased drag forces the satellite to descend more rapidly and eventually burn up upon re-entry into the Earth's atmosphere. Examples of drag enhancement devices include the DragEN system by Saber Astronautics and the Gossamer Orbit Lowering Device (GOLD) by Global Aerospace.
Electrodynamic Tethers
Electrodynamic tethers are long, conductive wires that are deployed from a satellite and use the Earth's magnetic field to generate an electromagnetic force, causing the satellite to decelerate. This deceleration lowers the satellite's orbit, eventually leading to atmospheric re-entry and disintegration. While electrodynamic tethers have not yet been widely adopted for small satellite deorbiting, they have been successfully demonstrated on larger satellites, such as the Japanese H-II Transfer Vehicle (HTV).
Propulsion-based Deorbiting
Some small satellites are equipped with onboard propulsion systems, such as chemical or electric thrusters, which allow them to change their orbits and perform controlled deorbit maneuvers. These propulsion systems can be used at the end of a satellite's operational life to initiate a controlled re-entry into the Earth's atmosphere, ensuring the satellite burns up upon re-entry and does not contribute to space debris.
Active Debris Removal
While not a deorbiting technology per se, active debris removal (ADR) is a complementary approach to maintaining a cleaner space environment. ADR involves using specially designed satellites or robotic systems to capture and remove defunct satellites and other space debris from orbit. These removal systems can then use onboard propulsion or other deorbiting technologies to dispose of the captured debris safely. Examples of ADR concepts include the European Space Agency's e.Deorbit mission and Astroscale's ELSA-d spacecraft.
A More Sustainable Space Environment
By incorporating these deorbiting technologies and responsible end-of-life practices, small satellites can help mitigate the risk of space debris and contribute to a more sustainable space environment. As the small satellite sector continues to grow, it is essential for satellite designers and operators to prioritize the adoption of these technologies to ensure the responsible and sustainable use of outer space for generations to come.
More Details
Chapter 13 of this document provides detailed information on state-of-the-art deorbit technologies.