Iron Lung v2.3-Skidrow

Decades ago, every known star and habitable planet mysteriously vanished, along with whatever and whoever happened to be on them, leaving behind an empty universe of asteroids and lifeless moons where the only remnants of humanity are those who were on space stations or starships at the time. With supplies gradually dwindling and infrastructure falling into disrepair, the survivors have spent the subsequent years frantically searching for any trace of remaining natural resources. Up until now they have been unsuccessful…

There is only a single porthole on the sub, and it needs to be closed due to depth pressure, so you have to navigate purely via an incomplete map, proximity sensors, sound, and a primitive external camera which can be used to take the pictures you need to complete your mission, or to get a grainy low resolution visual of what’s happening outside.

Then, a mysterious anomaly known as a Blood Ocean (which is exactly what it sounds like) was discovered on an otherwise barren moon. It’s not the first Blood Ocean found since the vanishing, but initial scans show a collection of potentially useful anomalous locations in a deep undersea (underblood?) trench that require further investigation.