Ganymede Systems are the main antagonists of the 2017 Doctor Who episode "Oxygen". They are a ruthless future corporation that holds a monopoly on oxygen, which they force the general public and even their own workers to pay for. They also have no concern for their workers, killing them if their productivity drops rather than keep paying a worker who isn't making enough money back.
In the far future, unspecified circumstances lead to oxygen being scarce throughout Earth's interstellar colonies, with the mining corporation Ganymede Systems holding a monopoly on all existing oxygen, which they forced the general public to pay for. They also forced their own workers to pay for it in the name of profit.
At one point, one of Ganymede's mining stations, Chasm Forge, began to drop in productivity. Rather than continue investing money into a failing station, which the executives saw as wasting money, they ordered the crew's smart spacesuits to "deactivate their organic components", killing all but five crewmembers, whose smartsuits did not receive the command.
Discovering that five crewmembers had survived, Ganymede Systems issued another order to the smartsuits: eliminate all surviving crewmembers. The smartsuits managed to kill three of the survivors, but the time traveller known as The Doctor managed to protect the other two until he figured out what was going on. He then rigged up the station to explode if the remaining survivors were killed, meaning that Ganymede would lose more money if they continued with their plan, forcing the suits to give the survivors their oxygen tanks and allow them to live. The Doctor then took the two survivors, Ivan and Abbey, to the Ganymede head office to "raise Hell".
According to the Doctor, the scandal caused when Ganymede's actions were exposed lead to the collapse of the company.