Magic is the result of an omnipotent terraforming satellite the size of a small moon, but all the accumulated tweaks and additions to its API used by spellcasters will reset during a double-eclipse with the planet's other moon. How can I represent this mechanically?
In a setting I am building, the planet (named Amalthea) has two moons, Rhea and Namaka. Rhea appears a little larger and slightly redder than the Moon, and Namaka appears in about half of the size of the Moon, and is somewhat blue in color.
Namaka, though, is in fact an artificial moon, and is the source of magic on Amalthea. (Its coloration is due to its surface being entirely covered in solar panels.) It was built by the original settlers of Amalthea, as a tool for terraforming planets for colonization, but due to mismanagement an unforeseen double eclipse caused it to reset and ultimately triggering the collapse of the colony. (One of the biannual eclipses by Amalthea was immediately followed by a rarer Rhea eclipse, extending the total eclipsed duration further than Namaka's backup power could provide for.)
The way it worked was simple. A colonist with training as a Manager of Affairs for Global Engineering (typically referred to by the acronym "MAGE") would speak and use hand gestures to interface with computer systems located on Namaka via its omniscience scanner array, and command the planet's omnipotence beam array to create the desired effect.
After the collapse of the original colony, only fragments of knowledge about how to operate Namaka survived. Since directly controlling the omnipotence beam array is impossibly difficult to do by hand, modern spellcasters rely on layers and layers of poorly-documented subroutines and APIs accumulated over years of tweaks and additions by various individuals and groups.
Casters who prepare spells are in fact creating bindings between their verbal/somantic/material components and the desired API calls and parameters. Divine magic works by communicating with the shipboard AI rather than making API calls directly. Classes which don't need to prepare spells instead employ a high speed mind/machine interface protocol to upload entire routines on the fly, but with the loss of bionic augmentation from the world, only a few individuals brains are suitable for this direct interface and it is incredibly difficult or even impossible to teach someone how to do it. Planar locations are in fact just VR suites located onboard Namaka, or something like that.
So basically, magic works just the same as it does in every other setting, the main change being that the magic goes out for a few hours twice a year when Namaka gets eclipsed.
Another double eclipse looms in the future. When it occurs, it will reset to its initial state, clearing all the added subroutines and features that modern magic-users depend on, meaning that many spells will no longer be able to function correctly.
Existing magical societies and such will within a reasonable amount of time develop workarounds and start adding new stuff all over again, but until then, I need some way to keep the spellcasting PCs from being too underpowered, while not destroying the sense of the event.
How can I keep spellcasting classes from being too underpowered during this event?