Abstract:
Very-low Earth orbit (VLEO) spacecrafts are important for high-quality communications and Earth and space science observations. In order to overcome the upper atmospheric drag in the very-low orbit region and make the spacecraft steadily stay in orbit, the concept of air-breathing electric propulsion (ABEP) spacecraft was proposed and a series of related studies were produced. In this paper, the main flight constraints of air-breathing electric propulsion spacecrafts in orbit at an altitude of 150 km, including the normalized working fluid balance and energy balance, are analyzed, and the main factors affecting the very-low orbit maintenance of the spacecraft are proposed. In order to maintain the payload spacecraft in the very-low orbit altitude range (around 150 km) for a long time and maintain a certain payload coverage, this paper proposes two very-low orbit flight system schemes, including a flight system based on wireless power transfer technology and a 150 km-Perigee elliptical orbit flight system. The corresponding orbital height limit is calculated and the constellation construction scheme is given considering the payload ground coverage, and the feasibility and effects of the above two schemes are evaluated. In both schemes, the payload can maintain long-term ground coverage within an orbital altitude around 150 km, which can provide conditions for the construction of long-term stable communication networks, Earth observation, and scientific experiments in VLEO.