The aim of the authors Pätzold and Bird, 2001, is to show that the study: Velocity changes of the Giotto spacecraft induced during the flybys of the comets P/Halley and P/Grigg-Skjellerup, by H. Porsche, published in 1999 is not correct. This article replies. © 2001 Éditions scientifiques et médicales Elsevier SAS.
Porsche, H. (2001). Comments on the paper: Velocity changes of the Giotto spacecraft during the comet flybys: On the interpretation of perturbed Doppler data, by Pätzold and Bird. Aerospace Science and Technology. DUNOD Editeur. https://doi.org/10.1016/S1270-9638(01)01101-4