I'm writing a novel, and my protagonists are going to find a small spaceship that was placed in Europe during the arrival of the first humans in Europe. The Neanderthals would have still been there.
My idea was that the cave was situated close to some mountains and during the ensuing ice age and glaciation, erosion of the mountains buried the ship.
The ship can produce mining and repair drones and recreate any part of itself via advanced 3D printing.
Is it possible that it could still be working after 30 000 years while there was a 4+ meter layer of earth on top? (The drones were able to retrieve enough water to fuel the fusion reactor.)
I would also need a explanation as to why the drones wouldn't have removed the dirt on top, but why they were able to when the ship reactivates - or another means of freeing the ship.
The ship is approximately the size of a large airplane, and approximates the shape the B-2 stealth bomber.
As it stands, my thought process was that the drones were set to minimal-effort repair and maintenance, and removing the dirt wouldn't fall within the purview of those instructions, but I am open to suggestions.