Art director and concept artist Luca Nemolato worked on Power Rangers during the design phase, and the original concept renders look a bit different than the ones the costumes that surfaced on screen. Nemolato released images of all of the Rangers, and while they feature the same overall alien-themed design, they also weave in more militaristic textures and design elements (via Power Rangers NOW).
Take for instance the Pink Ranger. The helmet's main design is largely unchanged, but as you can see the lights all throughout are much more in-line with LEDs, and the textures on the silver parts of her costume are given an industrial metal finish. You can see it in the Black Ranger's suit as well, as the neck is segmented and the metal plates on the helmet are layered like modern body armor as opposed to looking more synthetic.
Costume designer Kelli Jones was responsible for shepherding the suits from concept form to practical design, and in an interview with Inverse, she described their vision for the final suits.
"It comes out of their skin," Jones explained. "It looks multi-dimensional and translucent. Weta, they're magicians. They had never done anything like that before. It was a lot of R&D from every single angle. They were stressed as anyone making those suits."
Once they were actually created, it was a painstaking process of fine-tuning them to work during filming. They looked amazing on film, but people had to perform stunt work in them, and that's why they went through about 250 versions of the costumes.
"Once we tweaked it to get it functional, we lost how cool it was," says Jones. "It was a tug of war. It was back and forth and back and forth until you finally go, 'This is right.'"
You can see the suits in action in Power Rangers, which is on DVD and Blu-ray now.