As a member of the new Fantastic Four, Sue was at first the weakest link. She could turn invisible (duh!) but that was it, and she wasn't particularly strong. But Sue eventually discovered that she had another power---the ability to create invisible force fields. Over the years, Susan became much more adept at using these powers. For example, instead of just using her force field for defensive purposes, Sue can also use them as a weapon to attack foes. Indeed, Sue has been able to single handedly defeat the Thing, the She-Hulk (both with altered personalities), Titania, and the Absorbing Man. Her force-field has managed to sustain attacks by nuclear explosions and the Hulk. Today, one can convincingly argue that she is now the most powerful member of the Fantastic Four.Furthermore, while Susan cannot fly, she can use her force field to elevate herself and others through the air---as high as ten miles above the surface of the Earth. (Valeria is especially fond of using this power to "surf" through the air, much to the chagrin of Susan, who worries about her daughter losing concentration in mid-air.) In addition to making herself invisible, Susan can also extend a field of invisibility to include other objects or persons. Finally, although this is not a "power" granted to her through cosmic radiation, Sue has trained extensively in martial arts since becoming one of the Fantastic Four and currently holds a black belt in judo, karate, and shaolin kung fu. Also, since her run in with Malice and Psychoman, she can move into people's minds that she has a connection w/ as in "Psychoman"...because he did the same to her....in a recent MK issue this is dealt with.