One of the challenges about missions to asteroids is staying attached to them when you land.
Many asteroids are described as nickel/iron, and we know that both nickel and iron have magnetic properties.
Is it possible to anchor to a nickel and/or iron asteroid with permanent or electromagnets on landing feet?
If so how close to the asteroid would we need to be to determine if it would be effective? (i.e. just before landing, or from Earth based testing)