Enabling & Support

Magnetic damping for spacecraft stabilization after end of life

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ESA / Enabling & Support / Space Engineering & Technology

735 - Abstract of the technology:

The present invention aims to ease future Active Debris Removal (ADR) missions and de-orbiting operations by providing passive stabilisation of the space system. Furthermore, this solution will mitigate the risk of fragmentation events and breaking-up of the spacecraft structure due to high speed tumbling rates, today one of the main contributors to in-orbit fragmentation events. 

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Description:

A safe and secure space environment is a requirement for all current and future space activities and the problem of space debris represent a threat for the future space sustainability. Analyses performed by ESA and NASA indicate that the only means of sustaining the orbital environment at a safe level for space operations will be by carrying out both active debris removal and end-of-life de-orbiting or re-orbiting of future space assets. ESA, through its Clean Space initiative, is devoting an increasing amount of attention to this problem, including activities for debris removal. 

Active debris removal (ADR) has a number of technical challenges and risks in terms of rendezvous and capture of the non-operational satellite. One of the main sources of risk for such mission is achieving the necessary attitude for capture considering the target tumbling motion. Passive stabilization methods like magnetic damping systems installed on-board the target satellite can limit the rotational rate of the satellite at end-of-life, in turn simplifying and de-risking significantly an ADR mission to remove it.  

In the presence of a varying magnetic field, electrical currents are induced in conductive materials, which generate an opposing magnetic field to the field that produced them. It has been observed that the major part of the satellites, once their attitude is not controlled, start tumbling with rates that can go as high as 20 deg/sec. The passive damping of the tumbling motion of an uncontrolled satellite can be achieved by making use of the magnetorquers already on board for a new function after the satellite’s End-of-Life.

Figure 1 Conceptual Example of the magnetic behaviour
Figure 1 Conceptual Example of the magnetic behaviour

This invention is based on the short-circuit of magnetorquers activated by an autonomous trigger at the end of life. Given the efficient magnetic design of the magnetorquers, they will maximize the currents induced by the varying magnetic field resulting from the tumbling motion of the satellite, with the expected result to reduce the tumbling rate of the satellite. This solution will ease significantly active debris removal missions and deorbiting operations and with minimum impact on the host satellite.

Considering the torques which Earth’s magnetic field can produce on the vehicles, these devices are only useful for satellites in LEO.

Figure 2. Test set up to validate theoretical model
Figure 2. Test set up to validate theoretical model

Innovations and advantages:

  • Relatively simple and cheap development
  • Robust
  • Passive damping of the tumbling motion (to be used in inactive objects in LEO)
  • Low impact at system level
  • Facilitation of on-orbit autonomous operations
  • Reduction of the risk of in-orbit fragmentation and debris generation

Domain of application:

The magnetic damping concept could find applications in any fields involving motions/vibrations damping through a magnetic field by using a passive device.