In 2018, Kevin Bell, Staff Counsel at NGO Public Employees for Environmental Responsibility (PEER), received information from a whistleblower about a new satellite thruster under development that used mercury — a highly toxic liquid metal — as a propellant.
The company — Apollo Fusion — was in the process of selling its tech to space companies like SpaceX and OneWeb, who were in the planning stages of putting new mega-constellations of several satellites into orbit. The whistleblower was apparently motivated by concern that these systems would discharge mercury into the upper atmosphere, which would then make its way back down to Earth.
