@_Anonym0us_FL_ Iron dissolved in a solution eg with an acid or glass is not magnetic. If you added the ferris sulfate to the rock and then oxidized it to iron oxide then it would indeed make the rock magnetic.
@Stogy11 actually, I think I've thought of the same thing and yeah, I'm pretty sure it will work. the main issue being that the material will need to be dry and not frozen. Unfortunately, it is neither this time of year.
@starman0708499 They can and almost certainly have but there is a huge difference between a few freeze-dried cells clinging to the side of a rover and the active biosphere that a human would bring with them.
@WyattListon@MatthewCappucci It will be like during a total eclipse when 99% of the sun is covered. That last little bit is still bright enough to burn eyes.