Inspired by the European Space Agency's HERA mission to investigate the Didymos binary asteroid system after NASA's DART mission kinetic impactor test, this dataset was created as the "Planetary defence challenge". Hosted on ESAs competition platform Kelvins, the task is to analyze measurements in form of simulated lightcurves that have been collected pre and post-impact. In total, 300 pairs of such pre- and post-impact measurements are provided. The goal is to estimate the β-factor, which is related to the momentum-transfer of the impactor and the axial ratio a/c of the secondary asteroid. The data of the lightcurve measurements contain time of measurement (in minutes) normalized total luminosity (maximum value: 1.0) For the first 200 lightcurve-pairs, the following information is given in parameters.csv: value of the β-factor (>= 1) J2 value of the primary a/c axial ratio of the secondary The goal of the challenge is to estimate the β-factor and a/c for the remaining 100 lightcurve pairs. For more details on the dataset and the competition, please visit https://kelvins.esa.int/planetary-defence/.