The stellar sources that contributed to the chemical and isotopic composition of the solar system, their mixing in the Galactic environment, and the evolution and longevity of the molecular cloud from which our solar system formed can be probed with isotopic measurements of presolar grains, meteorites, and comets. The isotopic compositions of cometary xenon (Xe) and krypton (Kr) measured in the coma of 67P/Churyumovcloud collision. These observations support two distinct r-processes contributing to the overall solar r-process abundance pattern.