[Previous] | [Session 37] | [Next]
C. Szopa, R. Sternberg, D. Coscia, F. Raulin (LISA, University of Paris 12)
According to laboratory simulations of irradiated ices, in situ analysis of comet P/Halley dust grains composition and observations of cometary atmospheres, it is now quite obvious that comets are important reservoirs of a wide variety of organic and inorganic compounds (1). As these molecules could have been brought safely to the Earth's surface (2), they could have participated to the prebiotic chemical evolution on our planet.
However, no direct information about the cometary nucleus molecular composition is currently available. That is the reason why, as part of the Surface Science Package of the ESA Rosetta cornerstone mission, the COmetary Sampling And Composition experiment (COSAC) (3) is designed to the in situ chemical analysis of the comet 46/P Wirtanen nucleus. The analytical part will include a gas chromatographic (GC) subsystem dedicated to the separation, identification and quantification of the chemical species vaporized by heating of the nucleus material.
Having developed a part of the GC subsystem, and more particularly the five general purpose GC columns (heart of the GC), we present results showing the analyzing capabilities of the columns and their associated detectors under the in situ operating conditions reproduced at the laboratory. The ability to analyze and identify a wide range of molecular species from noble gases to small PAHs is demonstrated, thus showing that the measurements which will be performed by the flight instrument could open, in the future, new perspectives in cometary and prebiotic chemistry studies.
This work was supported by a grant from the French space agency (Centre National d'Etudes Spatiales).
(1) H. Cottin, M.-C. Gazeau and F. Raulin, Planetary and Space Science, 47 (1999) 1141. (2) C. Chyba and C. Sagan, Nature , 355 (1992) 125. (3) H. Rosenbauer, S.A. Fuselier, A. Ghielmetti, J.M. Greenberg, F. Goesmann, S. Ulamec, G. Israel, S. Livi, J.A. MacDermott, C.T. Pillinger, F. Raulin, R. Roll, and W. Thiemann, Advances in Space Research, 23 (1999) 333.