HR: 1340h
AN: P53B-1253    [Abstracts]
TI: The survival of large organic molecules during hypervelocity impacts with water ice: implications for sampling the icy surfaces of moons
AU: Hurst, A
EM: a.hurst@abdn.ac.uk
AF: University of Aberdeen Dept Geology and Petroleum Geology, Meston Building University of Aberdeen, Aberdeen, AB24 3UE, United Kingdom
AU: * Bowden, S A
EM: s.a.bowden@abdn.ac.uk
AF: University of Aberdeen Dept Geology and Petroleum Geology, Meston Building University of Aberdeen, Aberdeen, AB24 3UE, United Kingdom
AU: Parnell, J
EM: gmi327@abdn.ac.uk
AF: University of Aberdeen Dept Geology and Petroleum Geology, Meston Building University of Aberdeen, Aberdeen, AB24 3UE, United Kingdom
AU: Burchell, M J
EM: m.j.burchell@kent.abdn.ac.uk
AF: School of Physical Sciences University of Kent, School of Physical Sciences Ingram Building University of Kent Canterbury, Canterbury, CT2 7NH, United Kingdom
AU: Ball, A J
EM: a.j.ball@open.ac.uk
AF: PSSRI Open University, PSSRI The Open University Walton Hall, Milton Keynes, MK7 6AA, United Kingdom
AB: There are a number of measurements relevant to planetary geology that can only be adequately performed by physically contacting a sample. This necessitates landing on the surface of a moon or planetary body or returning samples to earth. The need to physically contact a sample is particularly important in the case of measurements that could detect medium to low concentrations of large organic molecules present in surface materials. Large organic molecules, although a trace component of many meteoritic materials and rocks on the surface of earth, carry crucial information concerning the processing of meteoritic material in the surface and subsurface environments, and can be crucial indicators for the presence of life. Unfortunately landing on the surface of a small planetary body or moon is complicated, particularly if surface topography is only poorly characterised and the atmosphere thin thus requiring a propulsion system for a soft landing. One alternative to a surface landing may be to use an impactor launched from an orbiting spacecraft to launch material from the planets surface and shallow sub-surface into orbit. Ejected material could then be collected by a follow-up spacecraft and analyzed. The mission scenario considered in the Europa-Ice Clipper mission proposal included both sample return and the analysis of captured particles. Employing such a sampling procedure to analyse large organic molecules is only viable if large organic molecules present in ices survive hypervelocity impacts (HVIs). To investigate the survival of large organic molecules in HVIs with icy bodies a two stage light air gas gun was used to fire steel projectiles (1-1.5 mm diameter) at samples of water ice containing large organic molecules (amino acids, anthracene and beta-carotene a biological pigment) at velocities > 4.8 km/s.UV-VIS spectroscopy of ejected material detected beta-carotene indicating large organic molecules can survive hypervelocity impacts. These preliminary results are yet to be scaled up to a point where they can be accurately interpreted in the context of a likely mission scenario. However, they strongly indicate that in a low mass payload mission scenario where a lander has been considered unfeasible, such a sampling strategy merits further consideration.
DE: 1055 Organic and biogenic geochemistry
DE: 5420 Impact phenomena, cratering (6022, 8136)
DE: 6221 Europa
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting