Abstract: A nested tank construction for pressurized materials comprises first and second cylindrical tanks connected together so that they are axially aligned. The first tank comprises a dome end which is inverted so that it extends inwardly into the first tank and is under compression loading when exposed to pressure within the first tank. The second tank comprises a dome end which extends outwardly from the second tank and is under tension loading when exposed to pressure within the second tank. The first and second tank dome ends have a matching geometry so that the second tank dome end is nested into the first tank dome end. The first tank dome end is a honeycomb sandwich structure comprising an aluminum membrane, a honeycomb core adhered to the concave face of the aluminum membrane, and a fiber composite face sheet adhered to the concave face of the honeycomb core. The honeycomb sandwich structure is co-cured under heat and pressure.