By National Research Council, Division on Engineering and Physical Sciences, Space Studies Board, Mathematics, and Applications Commission on Physical Sciences, Committee on Planetary and Lunar Exploration
Since its discovery in 1610, Europa - one among Jupiter's 4 huge moons - has been an item of curiosity to astronomers and planetary scientists. a lot of this curiosity stems from observations made via NASA's Voyager and Galileo spacecraft and from Earth-based telescopes indicating that Europa's floor is kind of younger, with little or no proof of cratering, and made mostly of water ice.
More lately, theoretical versions of the jovian method and Europa have advised that tidal heating could have ended in the lifestyles of liquid water, and maybe an ocean, underneath Europa's floor. NASA's ongoing Galileo project has profoundly accelerated our knowing of Europa and the dynamics of the jovian procedure, and should let us constrain theoretical versions of Europa's subsurface structure.
Meanwhile, because the time of the Voyagers, there was a revolution in our realizing of the bounds of lifestyles in the world. lifestyles has been detected thriving in environments formerly regarded as untenable - round hydrothermal vent structures at the seafloor, deep underground in basaltic rocks, and inside polar ice. in other places within the sun process, together with on Europa, environments considered suitable with existence as we all know it on the earth at the moment are thought of attainable, or maybe possible. Spacecraft missions are being deliberate that could be able to proving their existence.
Against this heritage, the distance reviews Board charged its Committee on Planetary and Lunar Exploration (COMPLEX) to accomplish a finished research to evaluate present wisdom approximately Europa, define a method for destiny spacecraft missions to Europa, and establish possibilities for complementary Earth-based experiences of Europa. (See the preface for a whole assertion of the charge.)
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Extra info for A Science Strategy for the Exploration of Europa
Thomas, Cornell University, private communication, 1999). A more precise determination of the radii of the three principal axes of the ellipsoid defining Europa’s shape (accurate to approximately 100 m) would provide a crucial verification of the hydrostatic equilibrium assumed in the interpretation of the second-degree spherical harmonic gravity data. It would also provide an independent measure of C/MR2. To proceed further in the exploration of Europa’s interior after the completion of GEM requires determination of both the gravity field and topography of the satellite over the entire surface.
7. H. , “Evidence for a Subsurface Ocean on Europa,” Nature 391: 363, 1998. 8. T. , “Geological Evidence for Solid-State Convection in Europa’s Ice Shell,” Nature 391: 365, 1998. 9. E. , “Evidence for Non-Synchronous Rotation of Europa,” Nature 391: 368, 1998. 10. R. , “Rotation of Europa: Constraints from Terminator Positions,” Lunar and Planetary Science Conference Abstracts 28: 597, 1997. 11. V. R. Tufts, R. E. Geissler, “Formation of Cycloidal Features on Europa,” Science 285: 1899, 1999. 12.
The data from Galileo’s Near-Infrared Mapping Spectrometer (NIMS) show that Europa’s water-ice absorption features are distorted in comparison with those seen in pure ice. ” While this has commonly been interpreted as implying a contribution from hydrated minerals such as evaporite salts or clays in all regions of the satellite, it has been shown that light reflected from fairly clear ice with entrained bubbles or defects also exhibits band shifts similar to those observed on Europa. Many of Europa’s dark regions exhibit spectral characteristics that appear distinct from those of water ice, and these have been interpreted as being consistent with the spectral characteristics of water-bearing salts such as hexahedrite (MgSO4• 6H2O), epsomite (MgSO4• 7H2O), and natron (Na2CO3• 10H2O).
A Science Strategy for the Exploration of Europa by National Research Council, Division on Engineering and Physical Sciences, Space Studies Board, Mathematics, and Applications Commission on Physical Sciences, Committee on Planetary and Lunar Exploration