Dependence of the Beagle2 Trajectory on the Mars Atmosphere

Six days before arrival, the Mars Express spacecraft released the landing probe Beagle2. This paper extends a reconstruction of the lander’s drift trajectory from atmospheric entry to landing. Uncertainties of the initial drift trajectory and contributions by uncertainties in the atmospheric descent computation are mapped to the landing site. Parameters of key events during the descent are derived and compared to nominal target values. Special attention is paid to the dependence of the trajectory computation on the choice of the atmosphere model. Although different atmosphere models lead to differences in the computed trajectories, the final deviations of the landing points are small compared to the uncertainty by the initial state vector before ejection.