But in my defence it can be hard to tell the two apart in a genre devised for, and by, geeky males. Even Princess Leia, who started off less vacuous and more clothed than the average, ended up in the slave girl costume (cue gratuitous picture of Carrie Fisher).
However I've tried hard to pick
Sandra Bullock doesn't make the list as I haven't seen Gravity yet, and I'm only counting actual movies, not TV crossovers, so there's no Wilma Dearing (Buck Rogers), Deana Troy (Star Trek: The Next Generation) or Dana Scully (X Files).
So here we are, in chronological order, as I can't possibly rank them any other way, my top five sci-fi
Barbarella (Jane Fonda) in Barbarella (1968)
Staring the third Mrs Roger Vadim, Jane Fonda, it looked utterly bizarre and the plot is totally bonkers.
Having an actress strip off during the opening credits, and then proceed to sleep with every man she meets, doesn't perhaps sound the most liberating plot ever. But the world was still a pretty boring and straight place in 1968, and along with films like Blowup (1966) this was the sexual revolution as it happened.
Miss Fonda, of course, was also Hanoi Jane, smooching around North Vietnam even as the US Air Force wasted the Mekong Delta, so there is a bit of authentic radicalism here too.
Plus, after you've seen it, you'll never think of the band Duran Duran in the same way again.
Ellen Ripley (Sigourney Weaver) in Alien Quadrillogy (1979-1997)
She had also been a fairly sassy space fairer in the original film, and had held things together as the male members of the cast were devoured, but it was in the second film that she really kicked ass.
Aliens was the film that set the standard for sci-fi actioners. After that all future guns had to go chunk-chunk before they fired, and sci-fi heroines couldn't just scream and pout any more.
Rachael (Sean Young) in Blade Runner (1982)
Attractive, well dressed, susceptible to the charms of an older man and after four years she 'retires' and you're single again. Sounds good.
But she isn't just eye candy. What sets Rachael apart from the others on this list is that her struggle is an internal one, as she has to work out who she is, which of her memories are real and come to terms with her, possibly very short, lifespan.
To be honest, you wouldn't really expect Sean Young to pull a performance like that off, but I think she does just fine, as well as looking incredibly stylish.
The only question is, what does she see in Harrison Ford's rather wooden Decard? Rutger Hauer's Batty is the fella she should have ended up with.
Sarah Connor (Linda Hamilton) in Terminator 1(1984) and 2 (1991)
Casting is everything in cinema, and Arnold Schwarzenegger playing a robot was classic casting.
But Linda Hamilton as Sarah Connor was pretty inspired too. The mum who becomes a feral street fighter when her son is threatened is a bit of a cliche, but she manages to pull it off. In the second film she also has to wrestle with her feelings towards the titular cyborg, an emotionless killing machine who her son never-the-less regards as a father.
Well, I guess a few other mums have had to wrestle with that one too.
Dr Elleanor "Sparks" Arroway (Jodie Foster) in Contact (1997)
Her Dr Arroway is a serious scientist on a very serious quest. Women blasting aliens to pieces were old hat by 1997, but women scientists were rather rarer on screen.
They fiddled around with Carl Sagan's plot a bit, toning down the atheism and suggesting religion isn't all bad, but they also added twist that at the end, and Arroway ends up believes in aliens thanks to something close to Divine Revelation, which is a nice joke on rationalists like Sagan.
So that's my list; a sex kitten, a pair of heavily armed maternal types, some Art Deco totty and a brilliant scientist. So what does that say about me?