Passive Magnetic Attitude Control System Research Articles

Characterization and Testing of the Passive Magnetic Attitude Control System for the 3U AstroBio CubeSat

AstroBio CubeSat is a mission funded by the Italian Space Agency aimed at validating novel lab-on-chip technology, that would enable the use of micro- and nanosatellites as autonomous orbiting laboratories for research in astrobiology. This 3U CubeSat is equipped with a passive magnetic attitude control system (PMACS), including permanent magnets and hysteresis strips, which allows for stabilizing the spacecraft with the longitudinal axis in the direction of the geomagnetic field vector. This work presents the process followed for the experimental characterization of the system, performed on the engineering unit of the satellite by using a Helmholtz cage facility and a spherical air-bearing to recreate environmental conditions similar to the ones experienced during the orbital motion. The hysteresis strips are characterized starting from the determination of the hysteresis loop, from which the energy dissipation per cycle and the apparent magnetic permeability are extracted. Tests performed by using the Helmholtz cage and the air-bearing facility allows for further investigating the damping torque produced by the PMACS and validating the abovementioned parameters. Numerical analysis is then used to select the number of permanent magnets which allows for achieving a pointing accuracy within an error of 10∘ within 24 h from the deployment. The analysis of the flight data supports the results obtained from the experimental test campaigns, confirming the effectiveness of the proposed methods and of the PMACS design.

Modeling a Nanosatellite’s Angular Motion Damping Using a Hysteresis Plate

The angular motion of a CubeSat-type nanosatellite with a passive magnetic attitude control system is mathematically modelled. The attitude control system consists of a permanent magnet and hysteresis dampers in the form of a plate or a set of rods. The parameters of the hysteresis dampers are studied using a laboratory facility. A comparative analysis of the damping time using the plate and the set of rods is presented.

Angular Motion of the TNS-0 # 2 Nanosatellite after Launch from the International Space Station

Description of the passive magnetic attitude control system of the TNS-0 # 2 nanosatellite is presented. The parameters of the main components of the attitude control system are given and their choice is justified. Using telemetry data, the passive angular motion of TNS-0 # 2 was determined after processing measurements of the on-board sensors after launching from the ISS on August 17, 2017. The damping time of the initial angular velocity was estimated. The accuracy of magnetic stabilization after the end of transient processes was determined.

Tetrahedron formation of nanosatellites with single-input control

The present paper studies the formation flight of four nanosatellites forming a tetrahedron. The main goal of this research is to find the relative orbits of these satellites that, at least in the linear Hill–Clohessy–Wiltshire model, ensure finite relative motion and keep the volume and shape of the tetrahedron configuration. Since real motions of these satellites will differ from the linear ones, especially under the influence of the $J_{2}$ perturbation, active control is necessary. In addition, the limited size of the satellites does not allow us to use a complex 3-axis attitude control system. In the present paper we consider the passive magnetic attitude control system and suppose that the thrust direction is always aligned with the local geomagnetic field. In order to increase mission lifetime the control algorithm that minimizes the propellant consumption and keeps the tetrahedron volume and shape is investigated.

Results of the attitude reconstruction for the UniSat-6 microsatellite using in-orbit data

UniSat-6 is a civilian microsatellite that was launched in orbit on the 19th of June, 2014. Its main mission consisted in the in-orbit release of a number of on-board carried Cubesats and in the transmission to the UniSat-6 ground station of telemetry data and images from an on-board mounted camera. The spacecraft is equipped with a passive magnetic attitude control system. Gyros and magnetometers provide the information about the attitude of the spacecraft.The importance of reconstructing the attitude motion of UniSat-6 lies in the dual possibility, for future missions, of:•controlling the direction of ejection of the on-board carried satellites•having an accurate pointing for remote sensing operation.The reconstruction of the attitude motion of UniSat-6 is based on the data of the on-board Commercial Off The Shelf (COTS) gyros and magnetometers, downloaded at the passages over the ground station in Roma, Italy. At ground, these data have been processed with the UnScented QUaternion Estimator (USQUE) algorithm. This estimator is an adaptation of the Unscented Filter to the problem of spacecraft attitude estimation. The USQUE is based on a dual attitude representation, which involves both quaternions and Generalized Rodrigues Parameters. In this work, the propagation phase of the algorithm contains only a kinematic model of the motion of the spacecraft.This paper presents the results of the reconstruction of the UniSat-6 attitude using on-board measurements. The results show that the spacecraft effectively stabilized its attitude motion thanks to the on-board magnetic devices.

Hysteresis Nutation Damper for Spin Satellite

Hysteresis dampers are commonly used in Passive magnetic Attitude Control System (PACS). In PACS these rods produce a damping torque and reduce the satellite angular momentum and angular velocity. In this paper, a spin satellite was investigated which utilizes a passive magnetic damper consisting of magnetic hysteresis rods aligned with principal axis or spin axis of satellite and de-tumbling of the satellite, and the pure spin was achieved. An analytical model was presented to analyze hysteresis damper and a numerical simulation was performed to obtain dynamic properties of the spin attitude. In addition, assuming a dynamic imbalance, attitude behavior and damper effect on the spin rate of satellite were analyzed. The behavior of this passive magnetic stabilized satellite was simulated from the initial post separation phase.

Radio occultation constellation deployment via impulses along the geomagnetic field

The problem of radio occultation (RO) constellation deployment is examined. Of particular interest here is to study the feasibility of using passively stabilized small satellites. We consider a pair of satellites supplied with a passive magnetic attitude control system. The capsule containing two satellites is launched into a parking orbit and stabilized along the geomagnetic field direction. Then the satellites are pushed apart by a separation spring at some point of orbit. If necessary for braking, one or two thrusters may be placed along the stabilized axis of each satellite. Optimization of the separation point and velocity along with the ΔV required for possible braking thrust is carried out in accordance with some specific demands of RO missions. Atmospheric drag and Earth oblateness are taken into account as perturbations. It is shown that, depending on a mission scenario, the separation with either one braking thrust or no thrusts at all is preferable.

Elimination of relative secular drift of orbits of two satellites caused by polar oblateness of the Earth

A method of elimination of relative secular drifts in satellite formations is suggested for the case of influence of a perturbation due to polar oblateness of the Earth. The method is applied to eliminate relative secular drifts in the case when a satellite is controlled using an engine mounted along its orientation axis (the satellite is supplied with a passive magnetic attitude control system) and with the help of a solar sail installed on one of the satellites. Analytical results are confirmed by numerical simulation.

Development of formation for ionosphere sounding based on two satellites equipped with a passive magnetic attitude control system

The problem of orbital separation of two ionosphere sounding satellites with a passive magnetic attitude control system is studied. The objective function, i.e., the expression for the altitude of a connecting chord, is derived. Optimization of the separation point in orbit and V  required for separation is carried out for two separation modes: both in case of braking that completes the orbital configuration and without braking. The numerical estimation of the duration of along-track separation process and required V  is done.

Modelling of relative motion in multi-unit mechanical system with limited control

The paper is devoted to the development of a control algorithm to nullify the relative secular drift due to the Earth’s oblateness for the motion of Formation Flying. The chief satellite’s orbit is assumed to be circular and not controlled to maintain the formation. A deputy satellite is equipped with a passive magnetic attitude control system with a permanent magnet and low-propulsion thruster, distributed along the principal inertia axis in the same direction. Research is conducted on the possibility of eliminating the relative secular drift through limited control. The limitation consists in the constraint in the direction and magnitude of feasible control. In the present work, the control to eliminate the relative secular drift is analytically developed. The analytical results are approved by numerical simulation of the satellite motion, such as, of the first Russian nanosatellite TNS-0 No. 1.

Steady-state rotational motions of a rigid body with a strong magnet in an alternating magnetic field in the presence of dissipation

We consider steady-state rotational motions of a satellite, i.e., a rigid body with a passive magnetic attitude control system consisting of a strong constant magnet and a set of magnetic hysteresis rods. We use asymptotic methods to show that in the absence of dissipation there exists a one-parameter family of steady-state rotations of the rigid body with the strong magnet and that this one-parameter family passes into an isolated solution if a model dissipation is introduced. The motion thus obtained was discovered when processing the telemetry data from the first Russian nano-satellite TNS-0 launched in 2005.

Mission and Constellation Design for Low-Cost Weather Observation Satellites

The mission and constellation design for acquiring weather images of Taiwan, Republic of China, is presented. The mission requires acquiring at least one image covering Taiwan per hour. The constellation is constituted of the low-cost microsatellites, which employ a passive magnetic attitude control system and an imagery system of miniature cameras. The coverage requirements, accessible coverage zone, access coverage, and access coverage gap, are defined according to the constellation design. The Walker constellation method is employed to calculate the minimum satellites in constellation for the mission requirements. The calculation result shows that the 14/14/0 constellation satisfactory meets the mission requirement. The 14/14/0 constellation is also extended to acquire the images of targets located in the certain specified geomagnetic latitude band (− − 5t o2 2deg) hourly, with a slight modification of imagery system of each satellite by using multicameras. An application to observe a typhoon as the moving target having 127 images acquired in 102 h in the warning area of Taiwan is also presented.

The nanosatellite Munin, a simple tool for auroral research

The scientific objective of the nanosatellite Munin is to collect data of the auroral activity over both the northern and southern poles. The satellite has been developed by Swedish Institute of Space Physics under international cooperation. The purpose of the Munin project is both to achieve the scientific objectives and to show that it is possible to achieve such objectives by a very small satellite. A passive magnetic attitude control system is used to stabilize Munin along the direction of an intensity vector of the local geomagnetic field. The paper presents the development of the attitude control system and gives a brief discription of the tools and algorithms used for the attitude determination.

Passive Magnetic Attitude Control System for the Munin Nanosatellite

The instrumental and applied problems related to the design of a passive magnetic attitude control system for the Munin nanosatellite are considered. The system is constructed from a strong permanent magnet and a set of hysteresis rods. These rods are made of magnetically soft material using a special technology, and they allow us to support the satellite orientation with respect to the local magnetic field vector with a given accuracy and time response. By using asymptotic and numerical methods, we investigate the satellite dynamics for different models of hysteresis. The issues concerning the arrangement of the rods and their interaction with the fields of permanent magnets mounted onboard the satellite are discussed.

Attitude control system for the first swedish nanosatellite “MUNIN”

The paper describes the passive magnetic attitude control system developed for the Swedish nanosatellite MUNIN, its composition, and the results of the mathematical modeling of the satellite motion around its center of mass under the effects of external torques and control by this attitude control system. The satellite MUNIN is to be oriented along the local vector of intensity of the geomagnetic field. The problems, which are expediently considered hereafter are formulated too.