An energy efficient and lighter-than-air high altitude platform (HAP) is disclosed that allows for sustained station keeping at high altitudes of about 50,000-80,000 feet for prolonged periods of time. The HAP includes an aerodynamically streamlined body that may have the topology of a torus. The body may be inflated with a lighter-than-air gas in an amount sufficient to provide lift to the high altitudes. The HAP has a duct extending through the pressurized body that diverts flow through the duct and reduces aerodynamic drag. The HAP may include one or more propellers situated in the duct to provide propulsion and maintain a given location of the HAP relative to ground. There may also be a control system, a solar energy collection system, an energy storage system, and/or any of a variety of payloads to accomplish various tasks, such as communication and/or situational awareness applications.