Research by D. Nna-Mvondo1, B. N. Khare2, 3 and C. P. McKay2 1. Centro de Astrobiologia (CAB) / CSIC-INTA, Ctra. de Ajalvir, km 4, Torrejon de Ardoz, Madrid, Spain, 2. NASA Ames Research Center, Moffett Field, CA 94035-1000, USA, 3. SETI Institute, NASA Ames Research Center, Moffett Field, CA
In planetary bodies, the chemical effects of impact by extraterrestrial objects may be related to atmospheric changes such as atmospheric erosion, i.e. substantial losses of the atmosphere, to atmospheric shock synthesis and to local or global endogenic chemical transformations of the surface depending on the scale of an impact.
For some icy satellites, scientists at NASA's Ames Research Center propose that meteorite impacts could be a source for organic synthesis in ices.
Recent observations of the surfaces of Jovian satellites like Europa, Metis, Almalthea and Thebe strengthen their hypothesis, revealing that they exhibit visible color variation (dark and bright coloration) in their surface material, at the impact sites or between the leading and trailing sides.
The scientists tested chemical synthesis induced by hypervelocity impacts on planetary ices using the pulsed laser ablation technique with Gas Chromatography-Mass Spectrometry (GC-MS)and Fourier transform infrared spectroscopy (FTIR) analytical methods. A solid-state Q-switched Nd-YAG pulsed laser (model DCR-1A, Quanta-Ray) was used to simulate hypervelocity meteoritic impacts.
The production of hydrogen peroxide (H2O2) in these experiments may give rise to new ideas regarding the chemistry occurring at the surface of icy satellites such as Europa, which shows various cratering features. Impact processing could be another local source of H2O2 on Europa. Also, such results have supported the hypothes that H2O2 detected by space observations on the Galilean moons, e.g. Europa, is probably formed by ion energies characteristics of magnetospheric ions from Jupiter.
Significance to Solar System Exploration
How do complex organic materials get to the surfaces of icy satellites such as Europa, Enceladus, Ganymede, Callisto, and Titan? Using pulsed laser illumination to simulate impacts on these icy surfaces, it helps determine changes in organic content, and therefore provide a deeper understanding of the chemical composition and evolution of the surface ices of satellites.
Written by Samantha Harvey
For more information about NASA Science Highlights and information on publication, please contact Samantha Harvey, Samantha.K.Harvey@jpl.nasa.gov.
Last Updated: 24 January 2011