A large space colony transport ship (100 colonists) set off for Europa to populate a colony recently built by drones (near future, the 2070s). The six-year flight was going well until unidentified space debris caused a massive rupture in the ship's hull, splitting the vessel in two.
Climate Control systems exist independently on each deck, so the environment can still support human life, and the solar panels that power them are still operational. Repairs to the spaceship are not feasible, and each half of the crew has to wait at least 6 years for a rescue vessel to reach them. The two parties cannot communicate with each other, cannot share resources, etc.
The group in the front half of the ship follows the Space Travel: Best Practices guide like a bible, and the group in the back finds a more traditional way to manage its people.
They had to bring food and water to Europa, so both have food and water although the front group has significantly more.
What are other systems that are required to operate in a space vessel to allow humans to live for 6 years in space?
What would be the first thing to break/ need repairs?