The operational plans for Ptolemy during the Rosetta mission

Ptolemy is a Gas Chromatography – Isotope Ratio – Mass Spectrometer (GC-IR-MS) instrument within the Philae Lander, part of ESA’s Rosetta mission. The primary aim of Ptolemy is to analyse the chemical and isotopic composition of solid comet samples. Samples are collected by the Sampler, Drill and Distribution (SD2) system and placed into ovens for analysis by three instruments on the Lander: COSAC, CIVA and/or Ptolemy. In the case of Ptolemy, the ovens can be heated with or without oxygen and the evolved gases separated by chemical and GC techniques for isotopic analysis. In addition Ptolemy can measure gaseous (i.e. coma) samples by either directly measuring the ambient environment within the mass spectrometer or by passively trapping onto an adsorbent phase in order to pre-concentrate coma species before desorbing into the mass spectrometer.