Aerogels of single wall carbon nanotubes (SWCNTs) have high electrical conductivity (~1000 S/m), have large surface area (~1290 m2/g), and are mechanically robust. We combined advanced synthesis and characterization with molecular dynamics simulation to develop a systematic and comprehensive understanding of how the mechanical properties of nanotube aerogels depend on pore geometry, pore size distribution, and the characteristics of the junctions between nanotubes to improve the performance and to predict an optimal design of nanotube based porous structures.