I was browsing backissues of the fanzine Challenger, and read a talk by Gregory Benford about why he writes science fiction. Benfords writing is interesting because he makes an effort to write about realistic scientists, doing science like real science. Gregory Benford and Kim Stanley Robinson are the authors I've read who are taking this seriously, and doing it well.
Reading this talk, and the introduction, I can't help admiring how Benford managed to have two parallel carreers. I wonder what he sacrificed to be able to do research and write many novels. Probably something I'm not prepared to give up. I hardly get my fanzine out.
I know that Alastair Reynolds used to work part time (I think it was 80 %) and write a little more than the rest of the time. As far as I know he finally gave up his research related job to write full time.
Also found this interesting article: Can You Survive in Space Without a Spacesuit?. It's not the first discussion I've seen on this, but it was nice. And it has a reference to another of these scientist-writers: Geoffrey Landis.