Passivation Strategies on Board Airbus ds Leo Pcdus

Abstract

Having in mind the increasing amount of spacecraft in orbit, the number of space debris becomes a growing issue. Regarding the space regions around the Earth to be protected, one of them is the Low Earth Orbit (LEO) one, for satellites with altitudes lower than 2000km. Even if the number of incidents in orbit caused by the spacecraft battery is very low when looking at the total number of satellite breakup events (around 3,6% – none of them were equipped with Li-Ion batteries) the uncontrolled nature of such events and their dramatic potential consequences make necessary a proper treatment, in the form of countermeasures that are fully justified taking into account the limited impact in mass and cost on the PCDU. This paper deals with the different strategies followed in the Airbus DS LEO PCDUs regarding the implementation of the passivation function in several LEO missions with different architectures (DET and MPPT solar array power conditioning). In the selection of the solution implemented in the frame of every mission, a key driver is the degree of advance in the test performed over flight representative battery modules regarding their safe behavior when deeply depleted after a long period in orbit with the passivation applied over the spacecraft.