Ironically, Star Trek is considered "hard sci-fi", even if there are other shows/books that are harder. The hardness of science fiction isn't related to how plausible the science backing it is, but how much effort the story puts into explaining the "science", and how internally consistent that explanation is. Trek spends a fair amount of effort into technobabble, and had dedicated technobabble writers whose job was to try to maintain consistency with those explanations.
Compare this with something like Star Wars (the movies, not third party novels), where nearly zero effort is put into explaining how magical Force powers work or why laser swords have a fixed length.
Hard sci-fi says "this is how this works", even if it's complete bullshit. Soft sci-fi says "just accept that these things work, so we can use them as plot devices".
Most public health programs have some available to give away, but commercially they're rare because few people want to pay over a dollar per condom for them.
What makes them nice is you can safely put one in hours before sex happens. Add some silicone lube (which they don't have a problem with), wear a loose skirt, and you have a perfect setup for spontaneous sex in a risky location.