Design of an Attitude Stabilization Electromagnetic module for detumbling uncooperative targets

One of the challenges of Active Debris Removal is related to the tumbling of the target satellite, when the chaser spacecraft has to approach and capture it. This paper presents the ASEM (Attitude Stabilization Electromagnetic Module) concept for detumbling debris in a low Earth orbit with the intention of mitigating risk during capture operations. This paper presents a preliminary design of a system whose purpose is to stabilize a target's attitude, using an external module equipped with magnetorquers. The device, initially carried by the chaser spacecraft, is attached to the body of the target satellite. The magnetorquers are then used to detumble the target so that the chaser spacecraft can perform a safe approach prior to capture. A simplified model is used in the initial design phase to optimize the mass of the system and to size the torque rods and power source. Alternative methods for attaching the ASEM to the target from the chaser spacecraft are discussed. In addition a novel magnetic control law suitable for this application is presented. The feasibility of the concept is tested in simulations using a model based on Envisat (assuming that the ASEM is already attached to the target). Results show that a module weighing less than 20 kg can stabilize an 8-ton satellite initially rotating at 1 rpm in 21 days.