Isogrid structures are commonly used for launch vehicles as load-bearing structures and/or tanks to hold fuel, compressed gases, etc. By using an isogrid tank (isotank) as a primary structural component of a small launch vehicle, weight and cost can be reduced. These isotank structures can be shaped as cylinders and integrated into the full vehicle. The maximum expected operating pressure for these cylindrical tanks can be found using equations in the NASA Isogrid Design Handbook and validated using Finite Element Analysis on a cylinder of equivalent thickness, without needing to model the isogrid pattern. Once an optimal isogrid design is found, manufacturing should take into account machining, welding, roll forming, and/or other manufacturing in order to create the complicated isogrid pattern and cylindrical shape. It is found that for a small number of 5-foot long isotanks with 12-inch diameter, machining directly into 6061-T6 Aluminum is both time and cost efficient while also minimizing the need for welding or roll forming. This tank can be directly integrated into a small launch vehicle.