Iodine used as a spacecraft propellant for the first time

22nd January 2021 By: Rebecca Campbell - Creamer Media Senior Deputy Editor

In what could very well prove to be a major development for space technology, a satellite has used an iodine propellant to alter its orbit around the Earth. This is the first time that iodine has been used as a propellant on a spacecraft. 

The iodine thruster was fitted to a commercial research nanosatellite designated SpaceTy Beihangkongshi-1. The thruster was developed by French startup ThrustMe, supported by the European Space Agency. ThrustMe was spun-off from France’s École Polytechnique and the Centre National de la Recherche Scientifique (National Scientific Research Centre). 

ThrustMe’s technology employs iodine propellant in an electric thruster. The thruster is used to control a satellite’s height above the Earth. 

So it could be used to extend the lives of nanosatellites employed on Earth observation or telecommunications missions, by boosting them into higher orbits when they start to fall towards the Earth. It could also be used to deorbit them, into the atmosphere, where they would burn up.

Iodine has a number of advantages. It is less expensive and needs simpler technologies than traditional propellants. Many traditional propellants are toxic, but iodine is not. At room temperature and pressure, iodine is solid, meaning it is cheaper and simpler to handle on Earth.

When it is heated, iodine sublimates. That is, it turns directly from solid to gas, with no liquid stage in-between. This characteristic is ideal for a simple thruster system. Iodine is also more dense that traditional propellants, with the result that it takes up less volume within the satellite.