ELECTRONIC	h   t   t   p   c o l o n   s l a s h   s l a s h   a s t r o g e o l o g y dot u   s   g   s dot g o v   s l a s h   p r o j e c t s   s l a s h   w g c c r e o p e n g i s	http://astrogeology.usgs.gov/projects/wgccreopengis	1