doi:10.2514/1.G004300engCalvo, M.Montijano, J.I.Rández, L.Elipe, A.Approximate trigonometric series expansions of some bounded solutions in the Tsien problemART-2019-123043INTHE last decades, studies on the dynamics of a spacecraft that is moving in the gravitational field of a celestial body and subjected to some low-thrust propulsion system have attracted the attention of many researchers in astrodynamics. Here, we consider a particular case, the so-called Tsien problem [1], in which the spacecraft moves in a circular Keplerian orbit (often referred to as the parking orbit), and after a given time t0 0, it is subjected to a constant outward radial acceleration. By using the integrals of energy and angular momentum, this problem can be reduced to a two-dimensional scenario. Denoting by r and ? the polar coordinates that give the position of the spacecraft in the plane of the orbit [1], the differential equations that define their motion are ...2019http://zaguan.unizar.es/record/10119810.2514/1.G004300http://zaguan.unizar.es/record/101198oai:zaguan.unizar.es:101198info:eu-repo/grantAgreement/ES/DGA-FEDER/E41-17Rinfo:eu-repo/grantAgreement/ES/DGA-FSE/E24-17Rinfo:eu-repo/grantAgreement/ES/MINECO/ESP2017-87113-Rinfo:eu-repo/grantAgreement/ES/MINECO/MTM2016-77735-C3-1-PJOURNAL OF GUIDANCE CONTROL AND DYNAMICS 42, 10 (2019), 2325-2330All rights reservedhttp://www.europeana.eu/rights/rr-f/info:eu-repo/semantics/openAccess