Observations taken by the R-Alice instrument monitored how light from bright stars was altered as it passed through the coma, a process often used for determining the contents of atmospheres of much larger bodies. These observations showed a substantial amount of molecular oxygen in the coma. Brian Keeney showed that when comet is closest to the Sun, there is a larger abundance of oxygen relative to water than the ROSINA measurements show from a year earlier. The detection of molecular oxygen in one of these ancient relics of our earlier solar system gives an insight into the original chemical composition of the protoplanetary disk that formed our planets, moons, asteroids, and comets. However, the volatility of molecular oxygen and the ease with which it can escape a small body like a comet makes it difficult to explain how something like 67P was able to hold on to this much oxygen after four billion years in the outer solar system. Explaining the molecular oxygen content of 67P will be one of the many challenges that comet scientists will face in analyzing the comet’s past.

One reason that it's hard to imagine how comets hold on to oxygen is because of collisions between comets, which might impart enough energy to drive off the volatile gases. Alessandro Morbidelli, Martin Jutzi, and Patrick Michel gave a series of talks about collisions on 67P. They analyzed the probability of 67P undergoing collision in the early solar system, the results of low speed collisions on the cometary nucleus, and whether it was possible to form two-lobe shapes from re-accretion of larger bodies. Morbidelli showed that the last collision that 67P had experienced was most likely between 250 million and 1 billion years ago, relatively recently in the scale of the solar system. The low speed collisions, Jutzi explained, would be unable to sufficiently heat the nucleus to the point that most volatiles would be lost but could create the double lobe comet. Re-accretion of bits of a larger body could form a similar shape, and again only experience local heating from the impacts. Both scenarios would allow the comet to retain a large amount of its primordial volatiles, something that is critical to making sure that molecular oxygen and similar volatiles were not formed after the comet through high energy particle impacts.