The attire of female characters in old sci-fi and fantasy projects has been very “generous” to the male audience over the decades. Today there are other demands in this regard (which we must follow closely), but if we go back to the '40s and '50s, the rules were basically two: lots of skin, and metal bras. Don't believe me? Then look at this gallery…
Of course, when talking about metal bikinis, it is impossible not to mention Carrie Fisher in Return of the Jedi, but the trained eye will recognize that attire is not exactly original. Some enthusiasts traced its origins to the universe of Valerian and Laureline (from which Star Wars seems to have borrowed a couple of things), however, its true explosion of popularity happened in the '40s and '50s.
Yes, the reason is obvious: there was a need to tempt potential readers, and nothing better than a semi-nude space damsel. Some were about to be annihilated-devoured-kidnapped, while others showed a position of power... but the final effect was the same. From the '60s things changed a little... although only a little. The miniskirts of Star Trek TOS were at the limit, and the gentlemen of the time, grateful.
