A human in a suit has to step foot on the surface of the body (or in the case of the smallest ones at least touch it with some part of their body)

First from this list resolves to 100%, second to 95%, all the way down to last at 0% (there are 21 on the list).

The list is somewhat arbitrarily chosen, as there a number of moons and dwarf planets missing, but where cuts have been made I've tried to choose the more interesting objects. Objects not on the list just don't interact with this question, including Mars. Remains open until twenty have been resolved.

[I know some of these strain beyond the bounds of what is technologically possible; you can buy them down]