The unique isogrid pattern is used to enhance the strength-to-weight ratio of a material. Thereby, the resistance against buckling is increased. Buckling was a major problem for early rocket designs like the Atlas rocket, which once collapsed under its own weight (video below) due to its extremely thin tank walls. The isogrid is an interwoven pattern of I-beams, which acts to increase the stiffness of the overall structure and minimise the amount of material needed.

Apart from its enticing features, the isogrid structure is extraordinarily expensive to manufacture. The commonly pursued route to manufacture such a structure is to start from a thick piece of metal and machine it down with a computerised numerical control. This technique leads to a waste fraction of 95%. For this reason, SpaceX did not use the typical isogrid structure, but obtained a similar effect with stir welded strengthening stringers.