It can't actually take 'true' colour pictures at all --- RALPH has sensors in blue, red, infrared and methane, but not green. I suspect they can probably synth

It can't actually take 'true' colour pictures at all --- RALPH has sensors in blue, red, infrared and methane, but not green. I suspect they can probably synthesise true colour-ish by comparing the monochrome images to the blue and red ones; subtract blue and red from overall brightness, and what you have left is green (ish). Enormously technical nigh-incomprehensible paper here: http://www.boulder.swri.edu/pkb/ssr/ssr-ralph.pdf http://www.boulder.swri.edu/pkb/ssr/ssr-ralph.pdf