The impact of the fluctuations in the locations of elementary radiators on the radiation properties of three-dimensional (3D) array antennas is studied. The principal radiation features (sidelobes level, beam squint) are examined based on illustrative examples. Some atypical behaviours, that are specific to 3D arrays, are highlighted. The effect of fluctuations is demonstrated via examples concerning non-uniform arrays. This study is important for designing beamforming strategies in case of constellations of (nano) satellites for space-bound remote sensing of the Earth and the Universe.@en