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On problems of active space debris removal using tethered towing

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On problems of active space debris removal using tethered towing

  1. 1. On problems of active space debris removal using tethered towing Vladimir S. Aslanov and Vadim V. Yudintsev Samara State Aerospace University (SSAU), Russia 6th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland)
  2. 2. Satellites with flexible appendages and/or fuel residuals Upper stages with fuel residuals Large Space Debris: 26th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland)
  3. 3. Tug-Tether-Debris system 36th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland)
  4. 4. • Analysis of the pre-capture motion of the debris • Pre-burn stabilization of the debris • Post-burn dynamics and stabilization taking into account properties of the debris (flexible appendages, fuel) • Post burn dynamics & motion of the center of mass • Atmospheric re-entry of the debris Problems need to be considered 46th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland) Solved Not yet solved
  5. 5. Re-enter into atmosphere Deorbit Catch & Stabilization Uncontrolled motion Operational stage Active Stage / Separation Stages 56th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland) Initial conditions for the upper stage type debris uncontrolled motion Initial conditions for the re-entry Initial conditions for the catch stage This stage determine safety of the ADR
  6. 6. The attitude motion of the upper stage (debris) can be predicted using the models of the perturbing forces of: • separation system • the Earth gravity&magnetic fields • the atmosphere • the Moon, the Sun etc. The motion of the upper stage 66th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland)
  7. 7. The motion of the non-operating satellite 76th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland) The attitude motion of the satellite (debris) can be predicted using the models of the perturbing forces and last telemetry data.
  8. 8. • Equations for the osculating orbital elements • Equations in non-inertial orbital frame • Flexible appendages: floating frame of reference formulation • Sloshing dynamics: pendulum equivalent models Mathematical model structure 86th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland) 1. Equations of the mass center 2. Equations of the attitude motion of the system 3. Equations for additional elements (fuel, flexible appendages)
  9. 9. Forces and Torques 9 • Tug’s thrust • Tether tension (depend on Young's modulus, cross section area, damping) • Aerodynamic forces • Gravitational forces and torques • Magnetic forces and torques • Sunlight pressure • Control forces and torques 6th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland)
  10. 10. • Debris • Flexible appendages • Fuel • Tether • Stiffness • Damping • Tug • Tether control Complex model of the tug-debris system 106th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland)
  11. 11. • Figure shows oscillations of the angles α between the tether and the axis Oyo of the orbital rotating frame with undesirably high amplitudes while θ is small. • Marked oscillations caused by the gravitational torque that is created by the difference between the gravity forces act on the space tug and on the orbital debris. Example: the influence of gravitational torque 116th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland)
  12. 12. Stationary point as a function of tether length 126th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland) F=0,3 N safe
  13. 13. Example: closely spaced frequencies 136th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland) • The amplitude of the tether vibrations is influenced by the vibrations of the solar panels and and vice versa. • At t=15 the deformation of the panel 2 reach the breaking strain (dotted red lines) causing structure failure.
  14. 14. Debris with fuel residuals 146th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland) • Sloshing liquid is modelled as an equivalent pendulum. • The oscillations of liquid are small
  15. 15. Example: Nonlinear vs. linearized formulation 156th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland)
  16. 16. We have developed the mathematical model of the attitude motion of the debris+tether+tug system: • Tug + Elastic Tether + Debris with flexible appendages • Tug + Elastic Tether + Debris with fuel residuals Conclusion 166th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland)
  17. 17. • Capture dynamics of debris (harpoon, net, lasso ...) • The stabilization phase after debris capture What we will intend to do? 176th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland) We will study: We will create comprehensive model for all stages: from the capture to re-entry
  18. 18. Rigid body debris [1] V.S. Aslanov, V. V. Yudintsev, Dynamics of Large Debris Connected to Space Tug by a Tether, J. Guid. Control. Dyn. 36, 2013. P. 1654–1660. [2] V. Aslanov, V. Yudintsev, Dynamics of large space debris removal using tethered space tug, Acta Astronaut. Volume 91, 2013, P. 149-156. Debris with flexible appendages [3] V. S. Aslanov, V. V. Yudintsev, Behaviour of Tethered Debris With Flexible Appendages Acta Astronaut. 104, Issue 1, 2014. P. 91-98. [4] V. S. Aslanov and V. V. Yudintsev Dynamics, Analytical Solutions and Choice of Parameters for Towed Space Debris with Flexible Appendages. Adv. Sp. Res. Volume 55, Issue 2, 2015. P. 660-667. Debris with fuel residuals [5] V. S. Aslanov and V. V. Yudintsev The motion of tethered tug-debris system with fuel residuals. Adv. Sp. Res. (Accepted for publication). Re-entry [6] V. Aslanov, A. Ledkov, Dynamics of towed large space debris taking into account atmospheric disturbance, Acta Mech. Volume 225, Issue 9, 2014. P. 1-13. Publications 186th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland)
  19. 19. Thank You for attention 196th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland)
  20. 20. • Vladimir S. Aslanov Prof., Head of the Theoretical Mechanics Department, Samara State Aerospace University aslanov_vs@mail.ru http://aslanov.ssau.ru • Vadim V. Yudintsev Associate Prof., Theoretical Mechanics Department, Samara State Aerospace University yudintsev@classmech.ru http://yudintsev.info Authors 206th EUROPEAN CONFERENCE FOR AEROSPACE SCIENCES (29 June – 3 July 2015, Kraków, Poland)

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