It's possible that the lack of work shortages on Earth mentioned by Lowell might be down to there being not that many people left to employ, meaning that the human species really is dying as a result of them having totally wiped out the natural environment.
The movie makes it seem like what Lowell was doing was noble, but if by this point humanity could survive without Earth's environment, was killing humans to save the domes justifiable?
If the human race was on its last legs as a result of the loss of the ecosystem (see Fridge Horror), then yes it is justified.
The rationale presented for destroying the domes is that they present a 'hazard to navigation'. Considering where they are (Saturn) and the vastness of space — this makes no sense of any kind. And there's the fact that the domes themselves, even if custom-built for the project, must have been very costly. They could easily have been re-purposed rather than destroyed. Oh,and nuclear detonation of the domes would actually make them MORE of a hazard, not less. Instead of one intact easy-to-spot object, now thousands of small radioactive hazards to navigation now exist.
Nothing is actually said about *why* they are instructed to destroy the domes rather than just jettison them. When the order is relayed to the crew, Anderson at Con Central says "I have been given no explanation", and there is no dialogue about them being a hazard to navigation. Additionally, at the end of the film when Anderson is telling Lowell that they're going to rescue him, he goes on to say that the last dome should simply be jettisoned and not destroyed - "It's awfully dark out here, so it would be safer if you don't blow it up", which makes even less sense.
Each freighter was carrying six domes each. Which makes one wonder; why were the domes fitted with nuclear det-charges in the first place? The project must have been hugely expensive and represented a substantial investment of time, energy and resources. And considering they represent Earth's last intact bio-systems, why makes plans to destroy them?
The domes *weren't* fitted with charges - they have to be specially rigged by the crew - but that does raise the related question of why the freighters were carrying a large supply of portable nuclear detonators (or "detornators", as is inscribed on the hero version of the prop used for close-up filming).
A more likely rationale for the destruction of the domes was that the company didn't want other people getting their hands on their property, with the domes themselves having become too expensive to maintain any longer. Throughout the film, you get the sense that humanity has simply given up on trying to preserve the natural environment.
Why does humanity need massive space freighters in the first place? Nothing is said about this, but logically, there must now be off-world colonies, presumably at least the moon and Mars. We're told that after the domes are jettisoned the freighters will be "returned to commercial service" (which suggests a pressing need for more space freighting), but we also learn that mankind can synthesise everything it needs (hence no need to grow plants/raise food naturally any more), so why can't the same technology be used to synthesise everything the colonies need and remove the requirement for massive space freighters?
The drones are shown to have all the necessary dexterity to perform the medical procedure of cleaning, stitching and dressing Lowell's leg injury, but he has to reprogram them specially for them to be able to do this. Surely this eventuality would have been foreseen and the drones would already have the necessary programming to allow them to be be switched to these tasks in case of crew incapacitation? Or are we to assume that nobody has previously thought of using the drones for this sort of work and Lowell is breaking new ground?
