Environmental concerns ground mercury-based satellite thrusters
UN takes steps to outlaw mercury propellant that could have seen tonnes of the heavy metal rain down on Earth every year
Using mercury as a propellant for manoeuvring satellites in Earth’s orbit has been outlawed by a UN resolution before it could get off the ground. The ban follows interest in mercury-thruster technologies, which could have seen the toxic heavy element fall back to Earth from the upper atmosphere, posing significant environmental and health risks.
Ion drives that propel small satellites traditionally use xenon and krypton because they have suitably high atomic masses for ion propulsion systems. However, their scarcity means alternatives are needed if demand is to be met by the tens of thousands of mini-satellites that are expected to be launched in the next decade, and beyond, as companies such as SpaceX and Amazon populate low Earth orbit with satellite ‘megaconstellations’ for broadband communications.