On a New Type of Combined Solar–Thermal/Cold Gas Propulsion System Used for LEO Satellite’s Attitude Control

This paper presents the development, construction and testing of a new type of solar–thermal propulsion system which can be used for low earth orbit (LEO) satellites. Currently, the vast majority of LEO satellites are fitted with a cold gas propulsion system. Although such a propulsion system is preferred, the service duration of an LEO satellite is limited by the amount of cold gas they carry onboard. In the case of the new type of solar–thermal propulsion system proposed in this paper, the cold gas is first transferred from the main tank in a cylindrical service tank/buffer tank which is placed in the focal line of a concave mirror. After the gas is heated by the solar light focused on the service tank by the concave mirror, it expands by opening the appropriate solenoid valve for the satellite’s attitude control. In this way the service duration of LEO satellite on orbit can increase by 2.5 times compared with a classic cold gas propulsion system. This is due to the propellant’s internal energy increase by the focused solar light. This paper also presents the results achieved by carrying out tests for the hot gas propulsion system in a controlled environment.

Measurement system for the parameters of satellite propulsion

Within the STRAuSS (Advanced Solar Thermal Propulsion System for Increasing of Satellite Operational Life) project to investigate the extension of a satellite operation period, a new valve type and a new type of nozzle were designed. Extending the period of operation of the satellite propulsion is an important factor for increasing its activity period and reducing the production and launch costs. To measure the force generated when releasing propellant gas from the satellite reservoir, a dynamic fine-scale force measurement system has been designed. This system also measures experiment parameters such as: simulated solar radiation size, 4 key temperature and nozzle pressure. The system controls the action of the propellant gas release valve and the activation of lamps that simulate solar radiation from outer space. The system is based on acquisition modules connected to a touch panel computer. Establishing the measurement system and its calibration was an essential step in performing the experiments within the STRAuSS project.