’ t ▁make ▁sense " ▁ ▁Pass ive ▁methods ▁of ▁increasing ▁the ▁orb ital ▁decay ▁rate ▁of ▁space craft ▁de br is ▁have ▁been ▁proposed . ▁Instead ▁of ▁rock ets , ▁an ▁elect rod ynamic ▁t ether ▁could ▁be ▁attached ▁to ▁a ▁space craft ▁at ▁launch ; ▁at ▁the ▁end ▁of ▁its ▁lifetime , ▁the ▁t ether ▁would ▁be ▁rolled ▁out ▁to ▁slow ▁the ▁space craft . ▁Other ▁propos als ▁include ▁a ▁boost er ▁stage ▁with ▁a ▁sail - like ▁attachment ▁and ▁a ▁large , ▁thin , ▁infl atable ▁bal lo on ▁en velope . ▁ ▁External ▁removal ▁ ▁A ▁variety ▁of ▁approaches ▁have ▁been ▁proposed , ▁studied , ▁or ▁had ▁ground ▁sub system s ▁built ▁to ▁use ▁other ▁space craft ▁to ▁remove ▁existing ▁space ▁de br is . ▁A ▁cons ensus ▁of ▁speak ers ▁at ▁a ▁meeting ▁in ▁Br uss els ▁in ▁October ▁ 2 0 1 2 , ▁organized ▁by ▁the ▁Sec ure ▁World ▁Foundation ▁( a ▁U . S . ▁think ▁tank ) ▁and ▁the ▁French ▁International ▁Rel ations ▁Institute , ▁reported ▁that ▁removal ▁of ▁the ▁largest ▁de br is ▁would ▁be ▁required ▁to ▁prevent ▁the ▁risk ▁to ▁space craft ▁becoming ▁un accept able ▁in ▁the ▁for ese e able ▁future ▁( without ▁any ▁addition ▁to ▁the ▁invent ory ▁of ▁dead ▁space craft ▁in ▁LE O ). ▁To ▁date ▁in ▁ 2 0 1 9 , ▁removal ▁costs ▁and ▁legal ▁questions ▁about ▁ownership ▁and ▁the ▁authority ▁to ▁remove ▁def unct ▁sat ell ites ▁have ▁st ym ied ▁national ▁or ▁international