FLYING AT THE EDGE – EXTREMELY LOW ALTITUDE OPERATIONS FOR THE GOCE MISSION

摘要

ESA’s Gravity Field and Steady-State OceanrnCirculation Explorer (GOCE) is operated in anrnextremely low Earth orbit. The spacecraft designrnfeatures a unique aerodynamic shape and employs dragfreerncontrol with an ion propulsion system to counteractrnthe atmospheric drag. While the routine mission ofrnGOCE at 260 km altitude has been very successful, it isrninevitably coming to an end once all consumables arernexhausted. To maximize the scientific return of thernmission prior to its end of life, ESA has started arncampaign to lower the orbit of GOCE even further,rndown to 229 km. This is a challenging endeavour,rnrequiring major re-evaluations and changes on bothrnspace and ground segment. This paper presents thernplanning and execution of the low orbit operationsrncampaign, focussing on the changes needed in the flightrnoperations segment, and the in-flight operationsrnexperience at the lowered orbit.