Galileo images and mosaics of Europa Options

[tedstryk]

I have worked on sprucing up some global views of Europa from Galileo. There are a few more global views I hope to get to eventually. But the best two at nearly full phase benefited a lot.



[Moderator note: There are several more threads containing Galileo Europa images but they all contain several inactive image links. The main threads are:
http://www.unmannedspaceflight.com/index.php?showtopic=2016
http://www.unmannedspaceflight.com/index.php?showtopic=2174
http://www.unmannedspaceflight.com/index.php?showtopic=2222
http://www.unmannedspaceflight.com/index.php?showtopic=2082
http://www.unmannedspaceflight.com/index.php?showtopic=2142 ]

[MarcF]

I love these mosaics of Europa. I just realize that the upper image of the G7ESAPEXCR observation corresponds to the region observed by Galileo NIMS and where clay-like minerals have been detected:
http://www.nasa.gov/jpl/news/europa-clay-l...ml#.UtHIpUrpz7I
A big impact structure should be localized just to the east, but no secundaries are visible.
I have never seen the SSI and NIMS data associated, may be it would be interesting to superpose them.
Regards,
Marc.

[Bjorn Jonsson]

A big impact structure should be localized just to the east, but no secundaries are visible.

There is bright terrain just east of the upper part of the G7ESAPEXCR observation but the resolution there is low and it's not far from the limb in the best images that show it so it's difficult to tell what it is.

I wonder if a color model of Europa could be constructed that assumes that the composition (in terms of color, not necessarily chemically), locally, is always at some point on a continuum between icy and non-icy. Then the limited set of color images could be used to model the obviously complex photometry function of both the icy and non-icy terrain, and re-render any B/W images according to that model. It seems like in the case of Europa, a model that simple wouldn't be far from the mark.

Interesting idea - this might work. The darker terrain is usually redder but it would probably be difficult not to confuse topographic shading with albedo variations unless the solar elevation angle is high (i.e. there are no shadows). It has occurred to me to 'cheat' (either manually in Photoshop or semi-automatically somehow) when colorizing hi-res B/W data with low-res color data. The problem is that the more reddish color of the narrow 'bands' can 'spill' into the adjacent bright terrain if there is a very big difference in resolution. This problem is especially severe in the leading hemisphere where I have to use the 12 km/pixel C9 data to colorize the 1 km/pixel I25 data.