As an author, I write romance in futuristic and medieval settings, and sometimes, I mix both into the same series, like in the Chronicles of Kassouk, where I pit a medieval society against an advanced technological race. And contrary to modern logic, medieval humans are smart, very resourceful and full of surprises... enough to outdo their betters. Everyone enjoys seeing the oppressed win in the end.
A number of new authors are now also writing medieval as well as science fiction novels, but this is not a new phenomenon. Marion Zimmer Bradley in the eighties and nineties wrote in both science fiction and medieval genres with her Mists of Avalon (Arthurian legends) series and her Darkover (speculative fiction) series, and she met with great success in both genres. Most of her readers did cross over the genres to read all her books.
Writing the past or the future is not so far apart. Research is still research. For the future, instead of researching historical facts, you research modern science in order to project where the next logical evolutionary step will lead, and what kind of future society it will likely engender. Creating an unfamiliar world and making it real to the reader, whether in the past or in the future, requires the same skills, the same kind of imagination that projects into a world with different sets of rules, a different political climate, different dress codes, eating habits, different laws and ethics, different religious beliefs, different taboos, etc.
The only thing that doesn't change through the ages is people. Although we would like to believe that we evolved over the last millennia, we really haven't. Despite our fancy laws, we still have serial killers and terrorists. Given the opportunity, any human being will behave in the same noble or despicable manner now as he or she would have centuries ago. And in the future, it will probably still be the case. Of course, in the future there also might be robots, cyborgs, and clones which might operate under a different set of rules. But is that so different from the rules controlling the slaves of ancient times?
The struggle for justice, however, like the need for love and freedom, are timeless and constant themes that keep repeating in the past, the present, and will most likely endure in the future. Because these needs are inherent to human nature.
In conclusion, whether a writer tackles the past or the future, what carries a story, beyond the action, adventure and plot, is human emotion. We all can relate to that. So I hope you try my medieval romantic series. It's not set in the future, but if you imagine it's on another planet instead of our own in the faraway past, it could very well be.
Blasters, Swords, Romance with a Kick