In developing technologies and techniques to ensure low-orbiting satellites are designed according to the concept of ‘D4D’ – design for demise, The European Space Agency’s (ESA) Clean Space initiative determined that an external carbon fiber reinforced polymer composite allowed a magnetotorquer to reach a complete demise at high heat flux level.

The ESA Clean Space initiative considers the entire lifecycle of space activities, from the early design stages to the mission’s end of life, to the removal of space debris.

As part of ESA’s Clean Space initiative, researchers took a 4 by 10 cm section of magnetotorquer designed to interact magnetically with Earth’s magnetic field to shift satellite orientation, placed it in a plasma wind tunnel at the German Aerospace Center’s (DLR) site in Cologne, then reproduced reentry conditions, melting it into vapor. The goal was better understanding how satellites burn up during reentry and to discover how to minimize the risk of endangering anyone on the ground.

Made of an external carbon fiber reinforced polymer composite with copper coils and an internal iron-cobalt core, the rod-shaped magnetotorquer was heated to several thousands of degrees Celsius within the hypersonic plasma. ESA Clean Space engineer Tiago Soares explained, “We observed the behavior of the equipment at different heat flux set-ups for the plasma wind tunnel in order to derive more information about materials properties and demisability. The magnetotorquer reached a complete demise at high heat flux level.”

In theory, re-entering space hardware is burnt up entirely in the course of plunging through the atmosphere, but pieces can make it all the way down to Earth with the potential for serious damage. As part of its CleanSat initiative, ESA is developing technologies and techniques to ensure future low-orbiting satellites are designed according to the concept of ‘D4D’ – design for demise.

Previous studies have identified some satellite elements which are more likely to survive the reentry process including magnetotorquers, optical instruments, propellant and pressure tanks, and the drive mechanisms operating solar arrays and reaction wheels. This testing activity of the external carbon fiber reinforced polymer composite is helping extend the understanding of reentry behavior and lead to safer outcomes.