I don't understand it either, but the article makes a stab at explaining why: "Verifying the functions of these glycoproteins requires precise measurements of

I don't understand it either, but the article makes a stab at explaining why: "Verifying the functions of these glycoproteins requires precise measurements of the normal growth rates of crystals over time. Yet this is difficult to do so on the Earth because of the natural convective flow around the growing crystal induced by gravity."