Can someone ELI5 the significance of this for non space scifi geeks ?
It also slightly raises the odds that genetically modified fungi and lichen might be able to metabolize and grow on Mars at least if suitably protected, which may have implications on astronaut food and oxygen production as well as, much more speculatively, terraforming. Further, it has implications on planetary protection – the measures we take to avoid accidentally infesting other worlds with Earth life.
It is literally incredible, and the title is misleading.
The fungi was in some kind of box that was filled with a lot of CO2, a little O2 and H2O, and other stuff to simulate the atmosphere on Mars.
That box was then placed outside the space station.
It wouldn't survive if it was just growing in space, outside the space station. Believe me, I'm outside of it right now and it is not going to be fun[1].
1: I'm about to start doing my taxes-- blecch-- here on Earth, which is technically outside of the space station.