Stable isotope studies of cometary analogue materials

Some preliminary experiments exploring the isotopic exchange of water and CO2 at low temperature are reported. The results indicate that isotopic signatures of these components may be lost even at sub-ambient temperatures and thus have implications for the storage of cometary nucleus samples during return to Earth. Photochemically produced organics are made up of species with different stability to combustion including some of high volatility and others which are quite refractory. These materials are worthy of consideration as cometary analogues for use in preparing for the return of cometary nucleus samples. Their study could also help in the interpretation of the data which will eventually be gathered from the comet samples themselves