In the future, the environment of Earth has been destroyed, with the only plant and animal life left being preserved in domed forests aboard American Airlines space freighters in orbit around Saturn. Freeman Lowell, a botanist onboard the freighter Valley Forge and apparently humanity's last environmentalist, tends to the forests religiously and hopes that they can one day be returned to Earth and used to restore it to its natural state. When the decision to reassign the freighters and destroy the domes is made, Freeman becomes obsessed with protecting them. He kills his crewmates and escapes with the last dome, assisted by three robot drones he names Huey, Dewey, and Louie. He must then escape discovery and survive a collision with Saturn's rings.
Not to be confused with the Mike and the Mechanics song of the same name, nor the trope Silent Running Mode.
- Artistic License Biology: Put simply, humanity cannot survive without the environment. The scenario of the film is blatantly impossible; if we wiped out the entire environment, we'd go with it. On the other hand, some of Lowell's statements do seem to subtly suggest that humanity really is on its way out with the loss of the ecosystem (see the YMMV page).
- Asshole Victim: While no less dramatic (and showcasing the point where Freeman starts to lose it), every scene showing the rest of the crew of the Valley Forge up until he murders them showcases said crew as a bunch of industrial-strength Jerkasses who sincerely don't seem to give a crap about the fact that they are blowing up the last vegetable life of Earth, and multiple animals (they even rejoice, because that means that they will finally be leaving their post).
- Award-Bait Song: "Silent Running" and "Rejoice in the Sun", both performed by Joan Baez.
- Bittersweet Ending: Lowell dies, and the last dome is lost in space. Though the last drone is tending to it, and the forest within is alive.
- Chromosome Casting: There aren't ANY women in this film.
- Cute Machines: Huey, Dewey, and Louie. Which ironically were played by double amputees.
- Crapsaccharine World: What little is told of Earth paints it this way: sure, there is no longer such a thing as work shortages... but there is the fact that humanity has killed all of the plant ecology on the planet...
- Drama-Preserving Handicap: The leg injury that Lowell gets during his rebellion eventually worsens and leaves him delirious (and having to seek Self-Surgery) and even after getting it fixed he is forced to hobble around and hold onto any supporting structures within grasp for the rest of the film.
- Driven to Suicide: In order to save Earth's last remaining plant samples, Lowell is forced to jettison the one remaining dome and destroy the Valley Forge before the Berkshire arrives, killing himself in the process.
- Explosions in Space: A relatively accurate depiction — nuclear explosions in space are just silent circular flashes that fade away.
- Future Food Is Artificial: And unfortunately, Lowell seems to be the only one who is being bothered by that (the other members of the crew of the Valley Forge either openly dislike the hand-grown food or just see it as a toy to play with in food fights).
- Green Aesop: Somewhat Anvilicious; but (especially at the time the film was made) Some Anvils Need to Be Dropped.
- Idiot Ball: Lowell has been taking care of the plants for years, then near the end of the film when he's on the wrong side of Saturn, comes to suddenly realize the reason they're dying is they need sunlight.
- Latex Space Suit
- Meaningful Name: Freeman Lowell.
- Minimalist Cast: Not counting the drones, there are exactly four on-screen characters in this film: Lowell, Barker, Wolf and Keenan, plus the heard-but-never-seen captain of the Berkshire.
- Mohs Scale of Science Fiction Hardness: For the most part, falls under One Big Lie—or rather, One Small Fib. The softest part of the movie is the unremarked-upon Artificial Gravity.
- No One Gets Left Behind: A rescue mission is launched from Earth, on the grounds that they couldn't leave Lowell stranded out there. Ironically Lowell doesn't want to be rescued.
- Product Placement: American Airlines will last for centuries apparently.
- Riddle for the Ages: Why were the forests ordered to be destroyed? The President himself was not given the reason, or so he says on his transmission sending the orders. Most likely, it had simply become too expensive to maintain them any longer.
- Sanity Slippage: Lowell gets more crazy as the film goes on.
- Self-Surgery: When the pain of the leg injury he got during his rebellion gets to the point where he's passing out and is delirious, Freeman reprograms the drones (after Reading The Freaking Manual on how to do so) so they can work on his leg.
- Space Is Noisy: Another of the small fibs of the "hardness" of the story's science. Still works in the sense that the scene where the domes are detonated one by one and Lowell snaps and decides to save the last one is full of standing-in Dramatic Thunder.
- Terra Deforming: The government policy that leads to the events of the film.
- Theme Naming: The freighters are all named after national parks - Valley Forge, Berkshire, and Sequoia.
- Title Theme Tune: Performed by Joan Baez.