It's not difficult, it's just a bit fiddly, there are things to watch for, it oxidises very quickly, so as you're prepping it, rubbing it with lemon is wise.
When zinc is exposed to the acid in the lemon juice, the acid oxidises, or removes electrons from the zinc, and the resulting positively charged zinc ions move in the solution.
Mars is filled with iron, and its oxidised iron, basically rust, turns into dust particles and in addition to the beautiful dunes, you have this red atmosphere sometime red all over the surface of the planet.