Attitude determination and control for centrifugal tether deployment on the ESTCube-1 nanosatellite

Abstract

This paper presents the design, development, and pre-launch characterization of the ESTCube-1 Attitude Determination and Control System (ADCS). The design driver for the ADCS has been the mission requirement to spin up the satellite to 360 deg·s −1 with controlled orientation of the spin axis and to acquire the angular velocity and the attitude during the scientific experiment. ESTCube-1 is a one-unit CubeSat launched on 7 May 2013, 2:06 UTC on board the Vega VV02 rocket. Its primary mission is to measure the Coulomb drag force exerted by a natural plasma stream on a charged tether and, therefore, to perform the basic proof of concept measurement and technology demonstration of electric solar wind sail technology. The attitude determination system uses three-axis magnetometers, three-axis gyroscopic sensors, and two-axis Sun sensors, a Sun sensor on each side of the satellite. While commercial off-the-shelf components are used for magnetometers and gyroscopic sensors, Sun sensors are custombuilt based on analogue one-dimensional position sensitive detectors. The attitude of the satellite is estimated on board using an Unscented Kalman Filter. An ARM 32-bit processor is used for ADCS calculations. Three electromagnetic coils are used for attitude control. The system is characterized through tests and simulations. Results include mass and power budgets, estimated uncertainties as well as attitude determination and control performance. The system fulfils all mission requirements.

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].…”

“…The length of the arm vector is 5 m (the middle of the tether). The moment of inertia is estimated to be 0.076 kg·m 2 [14]. The angle β is 20 • .…”

“…According to simulations, the ADCS is able to spin up the satellite in less than eight orbits. The subsystem is described in detail in [13,14].…”

“…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.…”