The need to limit the population of artificial debris in the near-Earth space motivates the development of efficient deorbiting propulsion systems. Electrodynamic tethers offer a valid and attractive alternative to conventional chemical thrusters since they impose a penalty in terms of deorbiting time rather than additional launch mass. We have designed a low-cost demonstration mission, where a reduced-scale deorbiting system will be carried, deployed and controlled by a microsatellite. Numerical simulations show that the proposed configuration of the electrodynamic system allows, even in absence of active tether current control, to maintain a stable tether attitude motion. This is obtained through a careful combination of bare and insulated tether segments. When active current control is applied, the tether libration angles are bounded to within 10 degrees. The closed-loop control laws make use of the in-plane and out-of-plane libration angles and rates, which are estimated through a newly developed extended Kalman filter. The estimator’s measurements are provided by two three-axis magnetometers mounted on the spacecraft structure and at the lower tether end-point, respectively. We show that this micro system is able to deorbit a LEO carrier spacecraft in about two months, demonstrating salient features of tether technologies and associated electrodynamic effects.
P. Tortora, L. Somenzi, L. Iess, R. Licata (2006). Small Mission Design for Testing In-Orbit an Electrodynamic Tether Deorbiting System. JOURNAL OF SPACECRAFT AND ROCKETS, 47, 883-892 [10.2514/1.15359].
Small Mission Design for Testing In-Orbit an Electrodynamic Tether Deorbiting System
TORTORA, PAOLO;
2006
Abstract
The need to limit the population of artificial debris in the near-Earth space motivates the development of efficient deorbiting propulsion systems. Electrodynamic tethers offer a valid and attractive alternative to conventional chemical thrusters since they impose a penalty in terms of deorbiting time rather than additional launch mass. We have designed a low-cost demonstration mission, where a reduced-scale deorbiting system will be carried, deployed and controlled by a microsatellite. Numerical simulations show that the proposed configuration of the electrodynamic system allows, even in absence of active tether current control, to maintain a stable tether attitude motion. This is obtained through a careful combination of bare and insulated tether segments. When active current control is applied, the tether libration angles are bounded to within 10 degrees. The closed-loop control laws make use of the in-plane and out-of-plane libration angles and rates, which are estimated through a newly developed extended Kalman filter. The estimator’s measurements are provided by two three-axis magnetometers mounted on the spacecraft structure and at the lower tether end-point, respectively. We show that this micro system is able to deorbit a LEO carrier spacecraft in about two months, demonstrating salient features of tether technologies and associated electrodynamic effects.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.