Symmetry Breaking DOI: 10.1002/anie.201409354 Molecular Chirality in Meteorites and Interstellar Ices, and the Chirality Experiment on Board the ESA Cometary Rosetta Mission Iuliia Myrgorodska, Cornelia Meinert, Zita Martins, Louis Le Sergeant dHendecourt, and Uwe J. Meierhenrich* Dedicated to Professor Volker Schurig on the occasion of his 75th birthday chirality · circularly polarized light · mirror-symmetry breaking · origin of life · Rosetta mission 1. Introduction The ESA Rosetta mission, [1] successfully launched in March 2004, has now completed its 10 year journey to comet 67P/Churyumov-Gerasimenko (67P/C-G). Contrary to its predecessor missions Giotto and Vega to comet 1P/Halley, [2] Deep-Space 1 to comet 19P/Borrelly, [3] Stardust to com- et 81P/Wild 2, [4] and Deep Impact to comet 9P/Tempel 1, [5] Rosetta is the first space mission designed and con- structed to follow a cometary nucleus through perihelion passage and to deposit a landing unit on the cometary nucleus. The Philae lander detached from the Rosetta space- craft on November 12, 2014 and soft-landed on the surface of the cometary nucleus, the morphology and chemical compo- sition of which is largely unknown. Philae contains the “Cometary Sampling and Composition” (COSAC) instru- ment, which is equipped with a chirality module for the in situ identification, separation, and quantification of organic molecules, including enantiomers, expected to be present in cometary ices. The planned analyses will provide essential information on the formation of the solar system and possibly on the origin of molecular asymmetry in biological systems. [6] Natures selectivity in the discrimination between left and right enantiomers has fascinated scientists since Louis Pas- teurs first investigations on chiral molecules. The origin of this distinctive and essential feature of homochirality, how- ever, remains elusive. A multitude of hypotheses and spec- ulations have been put forward during the last few decades. One possible scenario involves the photochirogenesis of small enantiomeric excesses (ee) in extraterrestrial matter, followed Life, as it is known to us, uses exclusively l-amino acid and d-sugar enantiomers for the molecular architecture of proteins and nucleic acids. This Minireview explores current models of the original symmetry-breaking influence that led to the exogenic delivery to Earth of prebiotic molecules with a slight enantiomeric excess. We provide a short overview of enantiomeric enhancements detected in bodies of extraterrestrial origin, such as meteorites, and interstellar ices simu- lated in the laboratory. Data are interpreted from different points of view, namely, photochirogenesis, parity violation in the weak nuclear interaction, and enantioenrichment through phase transitions. Photo- chemically induced enantiomeric imbalances are discussed more specifically in the topical context of the “chirality module” on board the cometary Rosetta spacecraft of the ESA. This device will perform the first enantioselective in situ analyses of samples taken from a cometary nucleus. [*] I. Myrgorodska, Dr. C. Meinert, Prof. Dr. U. J. Meierhenrich Institut de Chimie de Nice ICN, UMR CNRS 7272 UniversitØ Nice Sophia Antipolis, FacultØ des Sciences Parc Valrose, 06108, Nice (France) E-mail: uwe.meierhenrich@unice.fr Homepage: http://www.unice.fr/meierhenrich/ Dr. Z. Martins Department of Earth Science and Engineering Imperial College London (UK) Dr. L. Le Sergeant d’Hendecourt Institut d’Astrophysique Spatiale CNRS-UniversitØ Paris-Sud, Orsay (France) Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/anie.201409354. . Angewandte Minireviews U. J. Meierhenrich et al. 2  2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Angew. Chem. Int. Ed. 2014, 53, 2 – 13 Ü Ü These are not the final page numbers!