Very interesting! Both renditions are quite marvelous, though I do like Tyra in the rustic sort of color a bit more. I feel however that the antenna on her headset would be more justified on her more "futuristic" style outfit on the right. All in all however, both versions of Tyra are exquisite! Excellent work of art.
The dark blue tones on her flex-weave underlay (Well, at least that's what I think they look like!) compliments the main white color of the armor. In this, Tyra appears to be a sort of commander getting ready to lead a full scale battle. Tyra on the left however appears to either be in gear worn around the base while not on duty, or whilst out on a reconnaissance mission! Also I couldn't help but notice the white armor appears to have a bite mark on the upper part of the breastplate? Or perhaps that's just how the armor was forged, correct me if I am false.
I also noticed the background sketch is subtly different. Rivets in the armor along with her eyelashes below the eye instead of above. The rivets certainly add more detail, but sometimes it's nicer to keep it simple!
Anyway! Better cut myself off before this text becomes a wall. Hope to see more of this character!