Tunnelling Spores in Asteroid Belt

Question

I am trying to justify a fungal life-form that lives in an alternate version of the Kuiper Belt. The life-form is (loosely) based off of this article: https://www.zmescience.com/science/geology/fungus-eating-minerals/

The spores of my life-form are cast into space in all directions, and those that land on an asteroid (a very small number) composed of necessary materials (iron, water ice and oxygen) will consume those materials, tunneling through the asteroid as they do so. Extremely low temperatures would cause this process to last for thousands of years.

Eventually, they create a maze of tunnels and pits throughout the asteroid, similarly to the kind detailed in the article. As the life-form spreads and expands through the tunnels, it generates large "caps" (like mushrooms) responsible for releasing more dormant spores, which drift through the tunnels out into space until they land on another asteroid. As a result, by the time of my story, the life-form has spread through most of the asteroid belt. Once the caps have released their spores, they die, but without an atmosphere, they do not decompose, remaining planted in the tunnels of the asteroid.

Could this general concept work? Obviously, life in a vacuum is harsh, and radical temperature changes and radiation would be constant; however, I was under the impression that some fungi (like mold) can survive such conditions.

Answer 1

It might work, however keep in mind that, due the large distances between bodies in the Kuiper belt and the very low velocity that you can impart to the departing spores, it will take very long time for a spore to land on another body.

The most crowded section of the Kuiper Belt is between 42 and 48 times Earth's distance from the sun. The orbit of objects in this region remain stable for the most part, although some objects occasionally have their course changed slightly when they drift too close to Neptune.

Scientists estimate that thousands of bodies more than 100 km (62 miles) in diameter travel around the sun within this belt, along with trillions of smaller objects, many of which are short-period comets. The region also contains several dwarf planets — round worlds too large to be considered asteroids but too small to qualify as a planet.

It would probably work better if the fungi, after reaching a critical mass, would cause an explosion, breaking the body into smaller pieces and traveling attached to them: a spore can be diverted by the solar wind way more than a chunk of rock/ice, and you don't want to drift away from the region where the hospitable bodies are present.