 Loss of coherence in diffraction experiments with macromolecules. The Viennese groups of A. Zeilinger first, and then of M. Arndt, have performed important diffraction experiments involving macromolecules. The most relevant ones involve C\(_{60}\), (720 nucleons) (Arndt et al. 1999), C\(_{70}\), (840 nucleons) (Hackermueller et al. 2004) and more complex molecules (over 10,000 nucleons, Eibenberger et al. 2013, Fein et al. 2019). So far these experiments are not capable of testing the proposal of Alder, therefore even less the weaker proposal of GRW, for the collapse rate (Toroš, Gasbarri, and Bassi 2017). Significant technological development is necessary in order to probe these values, possibly by realizing the experiment in outer space where coherences can be maintained for longer times (Kaltenbaek, Hechenblaikner, et al. 2012). 