Deformation of space debris and subsequent changes in orbit during eclipse due to solar and Earth radiation fluxes.

Both solar radiation pressure (SRP) and Earth radiation pressure (ERP) can dramatically influence the orbit of space debris, particularly objects with a high area-to-mass ratio (HAMR objects). This work investigates how these forces cause HAMR obejcts to bend during eclipse and how the orbit and attitude behaviour eveolves.

One class of HAMR object is made from a piece of multi-layer insulation (MLI) that has broken free or spalled off from a spacraft. MLI is typically extemely thin and has very little structural rigidity. This means that as well as being subject to orbital changes the non-conservative forces can also deform the object.

Previous studies have investigated how the SRP on a flexible object varies and how this is coupled with the orbit of the object. The object is typically modelled as a small number of flat elements connected by linkages which allow the compsite object to mimic the material properties of a single piece of MLI type material. The use of a small number of connected flat plates allows for the analytical computation of self shadowing as well as the resulting normal and shear SRP forces.

In this work the structure of the piece of debris is modelled numerically using thousands of elements, allowing for the object to curl along any number of axes rather than simply fold around a single pre-defined axis. The incident radiation flux is computed on each individual element allowing for more accurate self shadowing as well as variable flux across the debris object. The deformation of the object due to the uneven flux encountered when travelling through the penumbra is calulated along with the effect of both the SRP and ERP incident on the object.