A Plasma Brake for CubeSat Deorbit: Coulomb Drag Sizing for a Negatively Biased Tether in the Ionosphere

This paper presents a computed design study of a civilian orbital-safety system based on Coulomb drag between a charged tether and ionospheric ions (plasma brake principle). It is a computed study of a civilian orbital-safety system, with no targeting application and no weapon application. Status: SIMULATED, NOT MEASURED. Under the stated assumptions the sizing gives a debye length m of 0.00407, a effective sheath radius m of 0.332, and a plasma drag force N of 7.63e-06. Further computed quantities include deceleration m per s2 of 1.91e-06; decay rate km per day of 0.301; approx days 550 to 250km of 998; bias power W est of 2. The design is sized end to end from the stated assumptions in the deposited computation, so every headline number can be reproduced, challenged and revised. Where the approach performs poorly, that result is reported at the same size as the favourable results: the limitations section names the conditions under which this design should not be chosen. The contribution is a complete, auditable sizing for one operating principle, intended to be compared like-for-like with sizings built on other principles for the same task.