In②0①④,theInternationalSpaceStationhadtomovethreetimestoavoidlethalchunksofspacedebrisandthereisanincreasingproblemofsatellitesmysteriouslybreakingdown.Withfirst-handaccountsfromastronautsandexperts,Horizonrevealsthescaleoftheproblemofspacejunk.Ourplanetissurroundedbyhundredsofmillionsofpiecesofjunkmovingat①⑦,000milesperhour.NowtheUSgovernmentisinvestingabilliondollarstotrackthem,andcompaniesaroundtheworldaredevelopingwaystoclearuptheirmess-fromrobotarmstonetsandharpoons.HorizoninvestigatesthesciencebehindthehitfilmGravityanddiscoverstherealityisfarmoreworryingthantheHollywoodfiction.