They certainly are by other people’s rules.
I would suggest Sunshine. I don’t know the physics behind the main problem they’re going to solve (it’s apparently based in real theoretical physics), but it does a better job than most of showing just how dangerous and isolated space travel is. They consulted with NASA a lot about the designs. Take a turn for the weird about 2/3rds of the way through, but not quite in a way that’s incompatable with hard sci fi.
Can’t agree there. I can accept that B5 isn’t hard SF, but it’s way harder than Star Trek, which has always been a joke.
B5 posits a few new assumptions - that there’s hyperspace where, if you can enter it, it’s far more condensed than real space, and hence you can move further than light would travel in a given time, and some races have artificial gravity. From there they extract a fairly logical world. Races that don’t have artificial gravity have ships that fire conventional thrusters and either rely on spinning sections or simply suffer zero gravity for the crew. Races with artificial gravity have ships that move in a way that you’d expect a ship to move if you were monkeying with the gravity. There’s a sensible economic and political layout to jumpgates. They don’t just invent new randomly named particles or technology to solve problems every week.
I guess it depends on your definition of hard, but B5 presents a world far more grounded in logic and consistency, makes up far fewer new things to drive its plot, is far less arbitrary, etc. It’s not even in the same ballpark.
You won’t see me arguing that Nightfall has been made into a terrific movie. 
Were the “nematodes” in Red Planet the alien tech? I remember them, but not home being alien; I thought they were part of the terraforming efforts.
I can’t see a reason why Sleep Dealer doesn’t fit what the OP is looking for, tho.
I went back and re-read the OP and have to comment on this:
This is an extremely limiting qualifier, and it seems to me that most of the movies within this limit aren’t going to really be science fiction as much as just “movies about stuff happening in today’s world”.
I’m gonna disagree with you on that, just like, oh, nearly everyone one else on the planet.
I think The Road could qualify as a post apocalyptic, hard science fiction. It never states what caused the cataclysm, but it could’ve been anything from nuclear war, a huge meteor, or (my pet explanation) Yellowstone blowing it’s top.
Why are they then Science Fiction? What is the “science” in a book or film that simply assumes a small upgrade in currently available tech?
I’m going to answer that the science lies in the assumed small upgrade in currently available tech. What part of that don’t you think of as “science fiction”?
No part. It takes no foresight to write a story ten years from now with faster computers, better tablets, smarter-smartphones. A story simply set a few years in the future, with more or less today’s technology isn’t Science Fiction, there’s no ‘science” in it.
James Bond or even Dick Tracy aren’t considered Science Fiction even tho the gadgets there weren’t available at that time.
Show me one story on this list that occurs in (what would be then) a few years past todays world with todays tech- but within one decades worth of expected tech advances.
“A Fall of Moondust” is SF, even hard SF even tho the techno is available today as it wasn’t in 1961.
Specifically, it turns into a slasher movie. Did Not Want.
Also, the “people instantly turn into lumps of ice when exposed to outer space” thing was really really bad science. Vacuum is a really good insulator.
By your definition, then, Stephenson’s Snow Crash isn’t science fiction. Or any story written in the 1950s about sending a rocket to Luna. Or any story written today revolving around less-than-fully-sentient robots. Or a story about nanotechnology. Or anything involving manipulating DNA.
The part where you are wrong is that you assume that the science has to be full-blown impossible by today’s standards. It doesn’t. Hell, I’ll argue that it can be science fiction as long as the science is central to the story, even if that science is fully realized today.
I have to agree that Sunshine does not fit the Hard SF requirements, but only because of the 3rd act. Other than that, it was a brilliant SF film. The repair sequence had me on the edge of my seat for the duration, in particular.
So glad I’m not the only one who’s seen Space Island One - pity it isn’t on DVD. Relevant io9 link.
I said it was hard sci fi, and I stand by it. Yeah, it’s got “unobtainium” in it, but it also has lots of good, technologic-y stuff. A movie can still be hard sci fi even it is has chase scenes and drama - a movie isn’t a chemistry textbook.
Logan’s Run had that “carrousel” ceremony, with the (30 year) old folk getting zapped while flying around in the air without some visible support.
Logan’s Run: There was also the dial-a-date/teleporter thingy Logan uses to meet the love interest of the film. (Jessica?)
In the 1950s moon travel stories were science fiction because there were so many unknowns. What wasn’t science fiction were the stories about fictional Mercury astronauts after the program was well defined but before there were any flights.
Hal Clement’s Mission of Gravity is usually seen as the epitome of hard science fiction, but it takes place on a planet in another star system with the assumption that humans have developed interstellar travel. In hard science fiction the science is unknown but not impossible, or, if impossible by today’s standards, a somewhat plausible explanation is given.
I see someone mentioned Fantastic Voyage above. Not hard sf, since it is impossible to shrink people like that without dire consequences for density. In Asimov’s novelization he put in something about them shunting the extra mass into hyperspace - I can just imagine him holding his nose as he typed that.
This spring I’m on a panel about predicting the state of my field in 2020. I don’t consider my statement to be science fiction - though I could make it so if I wished to.
So tell DrDeth, not me. I mean, all the 50s Moon stories do is extrapolate bigger rockets and better spacesuits and better machines than what we already had… so according to him, they weren’t science fiction, let alone hard SF.
And I disagree that stories about fictional Mercury astronauts before any actual flights weren’t science fiction.
One powerful idea that runs through many of Cameron’s movies is telepresence and remote interaction with a distant environment via telerobots.
This notion is the foundation of Avatar. Perhaps the biological puppets portrayed in the movie are on a distant horizon, but telepresence and telerobots are plausible in the near future.
This is a technology that might allow exploitation of resources in our oceans as well as beyond low earth orbit.
I wrote about Cameron & Telerobots here: Puppets, Telerobots and James Cameron.
There may not be any good storytelling potential or authorial skill just in postulating faster computers, but there certainly is in portraying what people use those faster computers for. If an author doesn’t do a very good job of showing that, well, then, that makes it bad science fiction, but it doesn’t mean it’s not science fiction at all.
I am unsure about nominating Surrogates starring Bruce Willis, the timeline presented in the movie is flat impossible(in one decade the tech not only is perfected it also has a penetration rate among the world’s population of 99%, how are dirt poor people buying surrogates and who is building the infrastructure in places like Somalia?) but aside from that its pretty hard and vaguely possible.
Also Runaway starring Tom Selleck, that could happen today if domestic and agricultural robots made big leaps.
The movie Looker is pretty hard until the end when they randomly put in a time stopping gun :smack:
And what about S1mone? With Deniro, a CGI actress is sold to the public as real and they buy it.
Would Cube qualify? I can’t think of any true implausibilities (other than perhaps the specifics of some of the booby traps.)
And I agree with Snowboarder Bo, for me, what qualifies as science fiction, is that science has to be central to the plot. Even in movies like Contagion, which takes place in present day, but it was a plot based on the very real possibility of a deadly virus and it’s implications should we see something so virulent, today or in the future.