Working on a less 'round' pixel Asteroid

The page draws a simple 2D asteroid to begin with and adds on. This is a pixel approach, where the page checks if the grid point is close enough to the center and draws a gray pixel for my asteroid if it is.
The next step is to mine the asteroid, refining for metals and volatiles and placing the slag outside, around the habitat for armor and radiation shielding.
Actually, the first step is to show up with a ship full of belters, like a wagon full of dwarves in dwarf fortress. Pick a point outside of the asteroid for the ship, which is a pressure vessel for habitat, engines, propellant tanks and storage. We can 'ground' the ship on the ateroid by having it move towards the asteroid. If ship bits generate where there is already rock bits, replace the rock and place it around the border of the ship. The page accumulates the number of rock bits being moving and places them after all the ship is created. Or, the page can generate the ship along a line from the point to the border of the asteroid...