E-sail test payload of ESTCube-1 nanosatellite

TL;DR

This paper describes the design and structure of the E-sail test payload on the ESTCube-1 nanosatellite, aimed at measuring plasma interactions to advance electric solar wind sail propulsion technology.

Contribution

It presents the detailed design and implementation of the E-sail payload, including deployment, charging, and measurement systems, for in-orbit plasma interaction experiments.

Findings

Successful deployment of the 10-meter tether in orbit

Charging system capable of ±500 V voltages

Initial observations of plasma interactions with charged tether

Abstract

The scientific mission of ESTCube-1, launched in May 2013, is to measure the Electric solar wind sail (E-sail) force in orbit. The experiment is planned to push forward the development of E-sail, a propulsion method recently invented at the Finnish Meteorological Institute. E-sail is based on extracting momentum from the solar wind plasma flow by using long thin electrically charged tethers. ESTCube-1 is equipped with one such tether, together with hardware capable of deploying and charging it. At the orbital altitude of ESTCube-1 (660--680~km) there is no solar wind present. Instead, ESTCube-1 shall observe the interaction between the charged tether and the ionospheric plasma. The ESTCube-1 payload uses a 10-meter, partly two-filament E-sail tether and a motorized reel on which it is stored. The tether shall be deployed from a spinning satellite with the help of centrifugal force. An additional mass is added at the tip of the tether to assist with the deployment. During E-sail experiment the tether shall be charged to 500~V potential. Both positive and negative voltages shall be experimented with. The voltage is provided by a dedicated high voltage source and delivered to the tether through a slip ring contact. When the negative voltage is applied to the tether, the satellite body is expected to attract electron flow capable of compensating for the ion flow, which runs to the tether from the surrounding plasma. With the positive voltage applied, onboard cold cathode electron guns are used to remove excess electrons to maintain the positive voltage of the tether. In this paper we present the design and structure of the tether payload of ESTCube-1.