It doesn't matter. Yours have to be purple to fool the retina scans, because you are not one of the regular astronauts -- their retina patterns are recognized by the security system at the Rock Lab.
You turn them purple.
There is an eye-color changing device just inside the Research Lab (north of the main base). Change yours temporarily to purple to fool the retina scan devices.
When you find Salerno at the BioDome, she escapes through the airlock, and drops her keycard. If you have already turned your eye color to purple to beat the retina scan, you can follow her into the Rock lab.
There is blue, red, brown, green, black, yellow, and purple (and maybe some other colors, I don't remember anymore) . But the eye color that is needed for completing Lunar Colony is purple.
Just as you enter the Research Lab (building north of the main base), you will see the eye-color research unit. It states that purple eyes may cause detection problems with retina scans. Change yours to purple (they will change back when you finish the quest).
Black.
Gold lettering, anchor and stars with a light blue ribbon banner.
From our view, Black.
You cannot enter the Rock Lab without a key card. You don't get one until it is dropped at the Bio Dome by Commander Salerno. This is later in the quest. You will, however, need to go to the Research Station to recover the Locator Device. While there, use the eye color changer to make your eyes purple. This will let you pass the retina scan.
blue
There is no right or wrong color to buy for the Nike lunar glide shoes. The best color to buy is the color you like the most. However, many people do like the orange version of the shoe.
The moon will go orange/red during a lunar eclipse, as the earths atmosphere distores the light from the sun.