SPACECRAFT ROBUSTNESS TO ORBITAL DEBRIS

摘要

The ever increasing number of orbital debris has already ledrnthe space community to implement guidelines andrnrequirements for “cleaner” and “safer” space operations asrnnon-debris generating missions and end of mission disposal inrnorder to get preserved orbits rid of space junks. It is nowadaysrnwell-known that man-made orbital debris impacts are now arnhigher threat than natural micro-meteoroids and that recentrnevents intentionally or accidentally generated so many newrndebris that may initiate a cascade chain effect known as “thernKessler Syndrome” potentially jeopardizing the useful orbits.rnThe main recommendations on satellite design is torndemonstrate an acceptable Probability of Non-Penetrationrn(PNP) with regard to small population (<5cm) of MMODrn(Micro-Meteoroids and Orbital Debris). Compliance impliesrnto think about spacecraft robustness as redundancies,rnsegregations and shielding devices (as implemented in crewedrnmissions but in a more complex mass – cost – criticality tradeoff).rnConsequently the need is non-only to demonstrate thernPNP compliance requirement but also the PNF (probability ofrnNon-Failure) per impact location on all parts of the vehiclernand investigate the probabilities for the different fatalrnscenarios: loss of mission, loss of spacecraft (spacernenvironment critical) and spacecraft fragmentation (spacernenvironment catastrophic).rnThe recent THALES experience known on ESA Sentinel-3, ofrnincreasing need of robustness has led the ALTRAN companyrnto initiate an internal innovative working group on thoserntopics which conclusions may be attractive for their primernmanufacturer customers.rnThe intention of this paper is to present a status of this study :rn1.Regulations, requirements and tools availablern2.Detailed FMECA studies dedicated specifically tornthe MMOD risks with the introduction of new ofrnprobability and criticality classification scales.rn3.Examples of design risks assessment with regard tornthe specific MMOD impact risks.rn4.Lessons learnt on robustness survivability of systemsrn(materials, shieldings, rules) coming from otherrnindustrial domains (automotive, military vehicles)rn5.Guidelines and Recommendations implementablernon satellite systems and mechanical architecture.