Well, she is space goo. The rockets would be from her Nadeshiko suit, but the skis are probably because goo's primary form of locomotion is sliding around. SOLU skis for extra mobility also kind of make sense, or else it'd have been much harder to stay mobile on jagged rocks. They probably just came from the SOLU adapting. Those skis did let Fourze punch the rockets off like the Meteor Galaxy limit break without losing any momentum, so it's not like they weren't useful.

Alternatively, Nadeshiko could have thought Gentarou would look good with skis. Maybe she did some space skiing during her travels? Plenty of frozen moons out there.

Alternatively alternatively, they needed a reason for Nadeshiko and Meteor to not be involved with the climax, and that was the only thing they could think of to give Fourze.