Long-Term Semi-Analytical Orbit Propagation Tool for Future European Launchers Design

Abstract

In a context of growing concerns about space debris, new regulations such as the French Space Act restrict the disposal of space objects after end of their operational life in order to mitigate the risks of collision in populated space regions. As a consequence, future underdevelopment European launchers have to meet these requirements, which can significantly impact their designs. As a result, Astrium Space Transportation has developed a fast and reliable long-term orbit propagator to integrate the natural fallout of upper stages into the design process of next-generation launchers. Based on semi-analytical solving of the Gauss equations, this propagator integrates so far the third-body force, the atmospheric drag, solar radiation pressure and a fourth-order zonal model (J2-J4) of the Earth gravitational field. Inter-validation against in-house numerical integrator and COTS software reveal the semianalytical approach leads to similar computational accuracy levels while significantly reducing the simulation time. Several application cases are presented to illustrate the tool capabilities and applications into the launcher design process. NomenclatureG = Gravitational constant a = Semi-major axis β = Ballistic coefficient γ = Velocity slope e = Eccentricity i = Inclination Ω = Right ascension of ascending node ω = Perigee argument r = Radius R eq = Earth equatorial radius n = Keplerian orbit pulsation M obj = Object mass λ = Longitude φ = Geocentric latitude Φ = Solar radiation power μ = Earth standard gravitational parameter K diff = Surface diffusion coefficient θ = True anomaly E = Eccentric anomaly C D = Drag coefficient ρ atm = Atmospheric density c = Light speed S ref = Reference surface for drag formulation Σ ref = Reference surface for solar radiation pressure formulation 1 Aerospace Engineer