ORBITAL EVOLUTION OF HIGH-ALTITUDE BALLOON SATELLITES

Abstract. We investigate the motion of artificial satellites withlarge area-to-mass ratios in high-altitude low inclined orbits,perturbedsimultaneouslybysolarradiationpressureandEarth’soblateness. Our study is based on recent theoretical advancesin circumplanetary dust dynamics (Hamilton & Krivov 1996).Applying these methods to the motion of balloon satellites, wewritedownandanalyzetheorbit-averagedequationsofmotioninplanarapproximation.Contrarytomanypreviousworks,ourconsiderationimposesnorestrictionsoneccentricitiesandradi-ation pressure strengths. The results show how the eccentricityand apses line of a satellite orbit evolve with time for variousarea-to-mass ratios, geocentric distances, and initial data. Ourspecial interest is with complicated dynamical effects arisingfromthetwoperturbingforcesabove.Wedemonstratethepos-sibility of dramatic orbital changes under small variations ofinitial data and force parameters. For typical balloon satelliteparameters, these unusual effects may take place at altitudesbetween one and two Earth’s radii.Key words: space vehicles – balloons – radiation pressure –Earth’s oblateness – celestial mechanics1. IntroductionResearch in dynamics of balloon-type satellites received con-siderableattentionsincelate1950s–early1960s,stimulatedbysuccessfuldesignandlaunchofsuchsatellitesasEcho-1,Echo-2,Dash2,Pageos(e.g.Prior1970,1972).Thegrossfeaturesofdynamics of satellites with large area-to-mass ratios at high al-titudescanbewellunderstoodbytakingintoaccounttwodom-inatingperturbingforces:directsolarradiationpressureandthequadrupole term in the geopotential expansion. This problemwas examined in a bulk of literature, starting from pioneeringworks by Musen (1960), Musen et al. (1960), Parkinson et al.(1960), Kozai (1961), Brower (1963), Polyakhova (1963), andothers.Itisworthyofmentioningthatoneofthemostpowerful