The Propellant Tanks from IHI Aerospace (IA) is a Spacecraft & Satellite Propellant Tank designed with volumes ranging from 3-1494 liters. These tanks are engineered to meet stringent international standards such as MIL-STD-1522A, JAXA, NASA and ESA ensuring reliability for critical space missions. It has a spherical and tear-drop geometries with internal devices including diaphragms, bladders, vanes, surface tension channel meshes, start baskets and sponge metal structures for efficient propellant management. The tanks are constructed using Titanium alloys, Aluminum or CFRP/Aluminum composites, combining lightweight design with high structural integrity. It is tested under rigorous conditions, including stress analysis, dynamic testing, leak-before-burst (LBB) evaluation and flow growth analysis.