ATTITUDE MOTION OF SPACE DEBRIS OBJECTS UNDER INFLUENCE OF SOLAR RADIATION PRESSURE AND GRAVITY

摘要

Space debris objects are resident space objects, which are neither actively nor passivelycontrolled any more. Those objects either are not any longer, or either never have beenin a controlled orbital or attitude state. As such, their orbital and attitude motion isgoverned by external forces only. In near geostationary orbits, the main sources of forceacting on the body are Earth and third body gravity eld, solar radiation pressure andEarth magnetic eld. Via optical observations astrometric positions and velocities maybe determined. Furthermore, light curves, brightness measurements over time, may bedetermined. Those light curves are a superposition of the lighting geometry, shape andattitude motion.In the current paper, two high area-to-mass ratio objects in near geostationary orbits areinvestigated. These objects, which were detected by Schildknecht in 2004, are extremelylight objects, which are most sensitive to orbital as well as attitude perturbations.Those objects are most likely shed o MLI materials, which may have rolled up andtherefore dierent reection properties as well as an oset between the center of mass andgeometrical center. Investigations have shown that those objects may end up in a veryrapid attitude motion, induced by solar radiation pressure as well as gravitational torque.The shape of HAMR objects in unknown, as materials MLI materials are suspected. Inthe current paper the assumption of a at rigid sheet is used.The coupled orbit and attitude dynamics are propagated and light curves are simulated.Those simulated light curves are compared to actually measured light curves, obtainedwith the one meter ZIMLAT telescope, located in Bern, Switzerland.