There are 15,000 traceable objects orbiting earth representing 6000 tons of material. There is now a real need for debris removal. The broom in the sky. This space craft sweeps debris using a plasma generated ion beam. The paper shows detailed modelling of the process showing problems like back-scattering of ions and charging of the debris.
A recent paper, “Spacecraft-plasma-debris interaction in an ion beam shepherd mission” by Filippo Cichocki, Mario Merino and Eduardo Ahedo appeared in Acta Astronautica, Volume 146, May 2018, Pages 216-227.
This paper presents a study of the interaction between a spacecraft, a plasma thruster plume and a free floating object, in the context of an active space debris removal mission based on the ion beam shepherd concept. The analysis is performed with the EP2PLUS hybrid code and includes the evaluation of the transferred force and torque to the target debris, its surface sputtering due to the impinging hypersonic ions, and the equivalent electric circuit of the spacecraft-plasma-debris interaction. The electric potential difference that builds up between the spacecraft and the debris, the ion backscattering and the backsputtering contamination of the shepherd satellite are evaluated for a nominal scenario. A sensitivity analysis is carried out to evaluate quantitatively the effects of electron thermodynamics, ambient plasma, heavy species collisions, and debris position.
- • The 3-dimensional distribution of densities/fluxes of ions, neutrals, and electrons.
- • The contributions of each species to the force and torque on the debris.
- • The electric potential of shepherd spacecraft, target debris and plasma.
- • The contaminating backsputtering flow towards the shepherd spacecraft.
- • The dominant role of charge exchange ions in shepherd spacecraft charging.