E-sail test payload of the ESTCube-1 nanosatellite

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 the E-sail, a propulsion method recently invented at the Finnish Meteorological Institute. The 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-m, 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 the 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 the 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.

Electric solar wind sail optimal transit in the circular restricted three body problem

“…The results discussed in this paper are part of an European research project [3,17,18] regarding the study and development of an E-sail thruster, and are intended to contribute to the definition of the set of possible scenarios [4] within which a selection is to be made for testing the practical feasibility of the propulsion system in a real mission. For this reason no performance comparison is made here with other propellantless thrusters, such as solar sails, nor with other low-thrust propulsion systems, as, for example, electric thrusters.…”

ESTCube-1 nanosatellite for electric solar wind sail in-orbit technology demonstration

“…The following system level tests were carried out to qualify for the launch: sine vibration, random vibration, shock, thermal cycling, and thermal vacuum. Individual tests performed separately on subsystems can be found in the relevant articles [12,14,15,17,19].…”

“…When the positive voltage is applied, on-board cold cathode electron guns are needed to remove the excess electrons to maintain the positive voltage of the tether. The subsystem is described in detail in [12].…”

“…The satellite design provides a detailed system level description and an overall subsystem level description, which includes the purpose, upper level requirements, and technical solutions. Detailed subsystem level descriptions and characterizations are presented in other articles in this issue [12,14,15,17,19].…”

“…• design and production of the tether [10,11]; • development of a tether deployment subsystem [12]; • development of an attitude determination and control subsystem for centrifugal tether deployment [13,14]; • development of a tether end mass (a mass at the end of the tether) imaging subsystem for monitoring tether deployment [15]; • development of an electron gun for keeping the tether at a high positive potential [12]; • development of a high voltage source for charging the tether and for powering electron guns [12]. A nanosatellite, ESTCube-1, has been developed to demonstrate the performance of the listed technologies and to perform the first in-orbit demonstration of the E-sail concept.…”