A dataset provided by the European Space Agency

URL ftp://npsa01.esac.esa.int/pub/mirror/CASSINI-HUYGENS/GCMS/HP-SSA-GCMS-3-FCO-DESCENT-V1.0
DOI 10.5270/esa-jr28leg
Abstract N/A
Description Content: Data Set Overview Science Objectives Mission Phase Definition Data and Data Processing Quality of Stage 2 Archived Data Creating Meaningful GCMS Archive Data File Names Structure of the DATA Directory & Comments Document Subdirectory Extras Subdirectory Dataset Review Data Set Overview = Gas Chromatograph Mass Spectrometer (GCMS) Instrument = The GCMS uses a quadrupole mass filter with a secondary electron multiplier detection system and a gas sampling system providing continuous direct atmospheric composition measurements and batch sampling through three gas chromatographic columns. The mass spectrometer used five electron impact ion sources with available electron energies of either 70 or 25 eV. Three ion sources served as detectors for the gas chromatographic columns and two were dedicated to direct atmosphere sampling and Aerosol Collector Pyrolyser (ACP) gas sampling, respectively. The multiple ion source approach allowed rapid switching between sample systems and prevented cross-contamination. The instrument was also equipped with a chemical scrubber cell for noble-gas analysis and a sample-enrichment cell for selective measurement of high-boiling-point carbon-containing constituents. The mass filter produced flat-top mass peaks that allowed rapid scanning in 5-ms steps of unit values of mass to charge (m/z) ratios over a range from 2 to 141. The nominal detection threshold was at a mixing ratio of 10^-8. Pressure reduction from the ambient pressure, ~3 to ~1,500 hPa (~1.5 bar), during the probe's descent to the vacuum level of <10^-4 hPa was achieved with micrometre-sized glass capillary arrays. A choice of two capillary arrays of different gas conductance was used for the direct atmosphere ion source to cover the wide pressure range during the descent. Gases were removed from the ion sources by conductance limited getter and sputter ...
Instrument GCMS
Version V1.0
Mission Description The majority of the text in this file was extracted from the Cassini Mission Plan Document, D. Seal, 2003. [JPLD-5564] The Cassini spacecraft, including the Huygens Probe, was launched on 15 October 1997 using a Titan IV/B launch vehicle with Solid Rocket Motor Upgrade (SRMU) strap-ons and a Centaur upper stage. The spacecraft used a 6.7-year Venus-Venus-Earth-Jupiter Gravity Assist (VVEJGA) trajectory to Saturn, during which cruise observations were conducted to check out, calibrate, and maintain the instruments as well as to perform limited science. After Saturn Orbit Insertion (SOI) (1 July 2004), the Huygens Probe separated and, on the third encounter with Titan, entered the satellite's atmosphere to make in situ measurements during an approximately 150 minute descent (14 January 2005). The Orbiter continued a tour of the Saturn system until mid-2008 collecting data on the planet and its satellites, rings, and environment. The Cassini Orbiter (CO) was a three-axis stabilized spacecraft equipped with one high gain antenna (HGA) and two low gain antennas (LGAs), three Radioisotope Thermoelectric Generators (RTGs) for power, main engines, attitude thrusters, and reaction wheels. It carried twelve orbiter instruments designed to carry out 27 diverse science investigations. The Huygens Probe (HP) was equipped with six instruments designed to study the atmosphere and surface of Titan. It entered the upper atmosphere protected by a heat shield, then deployed parachutes to descend slowly to the surface from an altitude of about 200 km. The instruments, with acronym and Principal Investigator (PI) or Team Leader (TL), are summarized below: Instrument Acronym PI/TL ----------------------------------------------- ------------ Orbiter: Cassini Plasma Spectrometer CAPS Young Cosmic Dust Analyzer CDA Srama Composite Infrared Spectrometer CIRS Flasar Ion and Neutral Mass Spectrometer INMS Waite Imaging Science Subsystem ISS Por...
Date Published 2006-05-05T00:00:00Z
Publisher And Registrant European Space Agency
Credit Guidelines European Space Agency, 2006-05-05T00:00:00Z, HP-SSA-GCMS-3-FCO-DESCENT, V1.0. https://doi.org/10.5270/esa-jr28leg