urn:esa:psa:context:instrument:rl.cosac 1.0 1.16.0.0 Product_Context 2021-06-15 1.0 Migrated from PDS3 catalog file. urn:esa:psa:context:instrument_host:spacecraft.rl instrument_to_instrument_host 10.1007/s11214-006-9000-6 Goesmann F., et al., COSAC, The Cometary Sampling and Composition Experiment on Philae, Space Sci. Rev., 128(1-4), 257-280, Feb. 2007. Reference to the instrument paper. Cometary Sampling and Composition Experiment Mass Spectrometer Gas Analyzer not applicable not applicable Instrument Overview =================== The Cometary Sampling and Composition Experiment (COSAC) is part of the Rosetta instrument payload. It is one of the evolved gas analysers of the Lander space-craft Philae. It provides data on the volatile fraction and its nature of the nucleus of comet 67P/Churyumov-Gerasimenko. Scientific Objectives ===================== The goal of COSAC is the identification of volatile molecular species in the cometary nucleus. Calibration =========== The calibration of the instrument is an ongoing process and the results are incorporated in the EGSE software. Operational Considerations ========================== Detectors ========= COSAC comprises two instruments: a gas-chromatograph (GC) with eight different columns each equipped with a thermal conductivity detector and a time-of-flight mass-spectrometer (MS) with a multi-sphere-plate as detector. More details are found in Goesmann et.al, 2005 Electronics =========== Details on the electronics of the instrument are described in Goesmann, et.al, 2005. Location ======== COSAC is mounted on the large Pi-plate in the warm compartment of Philae. Samples are delivered by the Sample Drilling and Distribution unit (SD2) to ovens located on the balcony of Philae. Operational Modes ================= COSAC can be operated in basically three different modes: GC mode; only the GC is used, MS mode; only the MS is used, or coupled mode where the GC exhaust is fed into the MS. All three modes may be run with samples from different sources like atmosphere, oven, enrichment capsule, or calibration gas. Subsystems ========== The sub-systems are described in Goesmann et al, 2005. Measured Parameters =================== The COSAC GC measures the retention times of molecular species in separation columns, the COSAC MS measures the time-of-flight of ionised fragments of molecular species.