okay, but headcanon that eiffel has the most gravity-defying curls
i'm talking locks that swirl around horizontal and vertical and diagonal, hair that will never be tamed, ever, except by the most brutal of haircuts or a truly toxic quanity of product
and when he started the mission, he had it buzzed short. it got longer over the years, and he stubbornly refused to cut it (or he forgot, or both) much to minkowski's protests
and on the sol, he keeps it tied up for the spacesuit so she doesn't notice, but the second he shakes his hair loose when they get back home she just bursts out laughing because the addition of gravity has made absolutely no change at all. his hair springs right back into a thick curly mess with no regards for the laws of physics.
and that's just the way he likes it. at least, as long as there isn't a toddler around that'll spring at the chance to shove her lunch into his hair.