Laura Resnick is the daughter of another SF author, Mike Resnick. She's won awards for both her romance novels (written as Laura Leone) and her fantasy short stories and novels, including the John W. Campbell Award for Best New Writer in 1993. She's the author of the Esther Diamond urban fantasy series, which is about an actress in NYC who keeps being pulled into supernatural happenings. I believe she's a hybrid author. She comments on The Passive Voice occasionally and shares her knowledge with other authors. Learn more about her on her website (which didn't load for me), on Wikipedia, and on Amazon.
Aviva Rothschild has written a book about graphic novels (you can find it here), but she's better known as the author of With Strings Attached, or the Big Pink Job. In this book, set in 1980, the four Beatles are reunited on an alien planet, are given new powers, and must work together to complete various quests to return home. Anyone who loves the Beatles or RPGs will love this work. After reading it, I became first a fan and then a friend of Aviva's. website.
She's currently working on a sequel, which hopefully will be ready this year. Learn more about Rothschild on her
Kristine Kathryn Rusch writes in multiple genres under multiple names and has won a Hugo for her work in editing The Magazine of Fantasy and Science Fiction. I'm most familiar with her The Fey Series, though I do have a book from her Retrieval Artist series on my TBR pile. She's a hybrid author these days; her wise Business Musings series taught me a lot about publishing and was a big influence on my decision to go indie. You can learn more about her and her work on her website, Wikipedia, and Amazon.
Mary Doria Russell was born in Elmhurst, IL, which is where I spent part of my childhood. Her first two books, The Sparrow and The Children of God, deal with religion and first contact with aliens. The Sparrow won several awards, including the Tiptree and the Arthur C. Clarke Award. I saw Russell when she was a Guest of Honor at WisCon in 1999. (That seems so long ago, doesn't it?) Russell has moved out of SF and is currently writing historical novels, but she doesn't deny that her first two books are SF. Learn more about her and her books on Wikipedia and Amazon.
If you have any more R authors to add to this list, please do so in the comments.