The ElectroDynamic Delivery Experiment (EDDE)

Abstract

The ElectroDynamic Delivery Experiment (EDDE) is proposed for a space demonstration. EDDE consists of an autonomous space vehicle powered by lightweight solar arrays, a bi-directional electrodynamic tether, and batteries for power leveling. The EDDE vehicle can modify its orbit repeatedly without rocket fuel, and can change all six orbital parameters by modulating and reversing the current flow in the conducting tether. The base spacecraft is connected to the service module by a 6-km-long electrodynamic tether, and is designed for 2 kW of power and a total mass of 180 kg. Tether lifetime of several years is achieved with a two-strand caduceus, with the strands connected every few meters. Tether libration is minimized by mass distribution and by active current control. The vehicle and tether system concepts are developed, the operational envelopes are examined, and potential applications are evaluated. The EDDE vehicle is about twice as fast as ion rockets for high-inclination orbital plane changes, and has much higher maximum delta-V capability. A proof-of-concept experiment is proposed for a low-cost space demonstration. This on-orbit experiment could include additional secondary payloads; for example, EDDE could place low-∆V, free-flying inspectors into arbitrary orbits from which they could approach selected objects without concern for tether dynamics or interference.

Swing Analysis and Control Research of the Space Tethered Combination in the Maneuver Process

“…It can be seen that the formation condition of the conical swing motion is related to the initial value of apex angle α 0 and the initial tangential velocity v 0 from Equation (6).…”

“…In recent years, many research teams have carried out a number of projects on flexible capture. The typical space flexible capture projects include the ROGER (Robotic Geostationary Orbit Restorer) of the ESA (European Space Agency) [5], the electric debris removal device EDDE (Electro Dynamic Debris Eliminator) of the American Star Company [6,7], the asteroid capture program ARM (Asteroid Retrieval Mission) of NASA [8,9], the Furoshiki satellite project of Japan [10,11] and so on. However, whatever the flexible capture system, in the maneuver process for the space tethered combination after target capture, the physical phenomena of collision, swing, tumbling and recombination between the flexible capture system and the targets can easily occur in a very weak gravity field, which will affect the measurement, and control and communication with the capturing platform.…”