SURVAVIBILITY TO HYPERVELOCITY IMPACTS OF ELECTRODYNAMIC TAPE TETHERS FOR DEORBITING SPACECRAFT IN LEO

摘要

This paper reports the results of 16 hypervelocityrnimpact experiments on a composite flat electrodynamicrntether for LEO spacecraft end-of-life deorbiting. Thernsystem is being developed within the EU FP7 BETsrnprogram. Impact tests were carried out at CISASrnimpact facility, with the aim of deriving failurernequations that include the impact angle dependence uprnto grazing incidence. Experiments were realised withrn1.5 and 2.3 mm aluminium spheres, at velocitiesrnbetween 3 and 5 km/s and impact angle from 0° to 90°rnfrom the tape normal. After a preliminary post-impactrninspection of the target, the damage extension on therntape was evaluated using an automatic imagernprocessing technique. Ballistic limit equations wererndeveloped in the experimental range using a procedurernthat allows to estimate the uncertainty in the failurernpredictions starting from the measurement of therndamage area. Experiments showed that the impactrndamage is very close to the projectile size in case ofrnnormal impact, while it increases significantly at highlyrnoblique impact angles.