Smart Nanosatellite Attitude Propagator ssl.engineering...
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Smart Nanosatellite Attitude Propagator ssl.engineering.uky.edu/snap Release Date: May 2011 Overview Nano-satellites such as CubeSats pose volume, mass, and power limitations on all components and modules within the satellite. Passive attitude stabilization techniques such as Passive Magnetic Stabilization and Gravity Gradient stabilization are effective and relatively simple methods to control the attitude of small satellites and provide basic pointing control. The Smart Nanosatellite Attitude Propagator (SNAP) was developed in MATLAB and Simuink to address the design questions of these stabilization systems. This is achieved by modeling all the major environmental effects of the desired orbit to study the on-orbit behavior and the effectiveness of the stability system in overcoming the disturbance torques. Orbit parameters, gravity gradient torque, the Earth’s magnetic field, magnetic torque, and magnetic hysteresis material behavior are all modeled in SNAP. Passive Magnetic Stabilization Samir Rawashdeh, James E. Lumpp, Jr. Space Systems Laboratory Electrical and Computer Engineering University of Kentucky Contact: [email protected] Underlying Simulink® Model Features Verification 0 5 10 15 20 25 30 0 20 40 60 80 100 120 140 160 180 Time (orbits) Angles (degrees) • Capabilities • - Satellite Passive Magnetic Stabilization Design • - Satellite Gravity Gradient Stabilization Design • - Studying Magnetic Hysteresis Material Performance • - Attitude Propagation (Gravity Gradient, Magnetic, and Hysteresis) • - Generation of STK (Satellite Tool Kit) Attitude Files for Animation • - Future Extension to Active Attitude Control Systems S. Rawashdeh, J. Lumpp, “Nano-Satellite Passive Attitude Stabilization Systems Design by Orbital Environment Modeling and Simulation”, AIAA Infotech@Aerospace 2010, Atlanta, GA The screenshot highlights the use of permanent magnets and magnetic hysteresis material to stabilize KySat-1, the first CubeSat developed by Kentucky Space. Unfortunately, KySat-1 was lost due to a contingency on the NASA Glory mission in March 2011. The simulation assumes a polar sun-synchronous orbit having an altitude of about 700 km and an inclination of 98˚ . In order to verify the accuracy of the Orbital Environment Simulator, several launched satellites employing passive stabilization techniques were simulated. Given the satellite design parameters, the orbital conditions, and the initial tumble rate, the actual on-orbit observations were compared to the simulation results. The results of the simulator were within the scope of the actual observations. The set of figures show PAMS: the Passive Aerodynamically Stabilized Magnetically Damped Satellite, which was an experiment on STS-77 in 1996. The attitude profile provided by NASA resembles to simulated profile to the same initial conditions. This scenario was simulated using an extended version of SNAP that incorporates an aerodynamic torque model. The Smart Nanosatellite Attitude Propagator incorporates the major environmental torques from a small-satellite perspective, as well as magnetic hysteresis material which is a passive solution to angular rate damping. The Simulink model essentially propagates the satellite’s attitude given its mass properties and orbit parameters. At each time step, the various environmental torques are calculated given the magnetic field at that point, the velocity, position in orbit, and the satellite orientation. The satellite position and orientation are modeled by a 6-DOF body model. Simulink offers a variety of differential equation solvers to propagate the models and obtain attitude reports for analysis and animation. Parameter Details Description Magnets Magnet Material Alnico-5 Total Volume 0.59 cm 3 Total Magnetic Dipole 0.5869 Am 2 (calculated) North Pole CubeSat -Z face Hysteresis Material Type HyMu80 Total Volume 0.15 cm 3 (0.075 cm 3 per axis) Coercivity 1.59 A/m Saturation 0.73 Tesla Remanence 0.35 Tesla Orbit Parameters Orbit Altitude 700 km Inclination 98˚ Design Summary
Transcript of Smart Nanosatellite Attitude Propagator ssl.engineering...
Smart Nanosatellite Attitude Propagatorssl.engineering.uky.edu/snap
Release Date: May 2011
OverviewNano-satellites such as CubeSats pose volume, mass, and power limitations on all components and moduleswithin the satellite. Passive attitude stabilization techniques such as Passive Magnetic Stabilization and GravityGradient stabilization are effective and relatively simple methods to control the attitude of small satellites andprovide basic pointing control. The Smart Nanosatellite Attitude Propagator (SNAP) was developed in MATLABand Simuink to address the design questions of these stabilization systems. This is achieved by modeling allthe major environmental effects of the desired orbit to study the on-orbit behavior and the effectiveness of thestability system in overcoming the disturbance torques. Orbit parameters, gravity gradient torque, the Earth’smagnetic field, magnetic torque, and magnetic hysteresis material behavior are all modeled in SNAP.
Passive Magnetic Stabilization
Samir Rawashdeh, James E. Lumpp, Jr.Space Systems Laboratory
Electrical and Computer EngineeringUniversity of Kentucky
Contact: [email protected]
Underlying Simulink® Model
Features
Verification
0 5 10 15 20 25 300
20
40
60
80
100
120
140
160
180
Time (orbits)
Angle
s (d
egre
es)
• Capabilities• - Satellite Passive Magnetic Stabilization Design• - Satellite Gravity Gradient Stabilization Design• - Studying Magnetic Hysteresis Material Performance • - Attitude Propagation (Gravity Gradient, Magnetic, and Hysteresis)• - Generation of STK (Satellite Tool Kit) Attitude Files for Animation• - Future Extension to Active Attitude Control Systems
S. Rawashdeh, J. Lumpp, “Nano-Satellite Passive Attitude Stabilization Systems Design by Orbital Environment Modeling and Simulation”,AIAA Infotech@Aerospace 2010, Atlanta, GA
The screenshot highlights the use of permanent magnetsand magnetic hysteresis material to stabilize KySat-1, thefirst CubeSat developed by Kentucky Space. Unfortunately,KySat-1 was lost due to a contingency on the NASA Glorymission in March 2011. The simulation assumes a polarsun-synchronous orbit having an altitude of about 700 kmand an inclination of 98˚ .
In order to verify the accuracy of the Orbital Environment Simulator, several launched satellites employing passive stabilization techniques were simulated.Given the satellite design parameters, the orbital conditions, and the initial tumble rate, the actual on-orbit observations were compared to the simulationresults. The results of the simulator were within the scope of the actual observations.
The set of figures show PAMS: the Passive Aerodynamically Stabilized Magnetically Damped Satellite, which was an experiment on STS-77 in 1996. Theattitude profile provided by NASA resembles to simulated profile to the same initial conditions. This scenario was simulated using an extended version ofSNAP that incorporates an aerodynamic torque model.
The Smart Nanosatellite Attitude Propagator incorporates the major environmentaltorques from a small-satellite perspective, as well as magnetic hysteresis materialwhich is a passive solution to angular rate damping. The Simulink modelessentially propagates the satellite’s attitude given its mass properties and orbitparameters. At each time step, the various environmental torques are calculatedgiven the magnetic field at that point, the velocity, position in orbit, and the satelliteorientation. The satellite position and orientation are modeled by a 6-DOF bodymodel. Simulink offers a variety of differential equation solvers to propagate themodels and obtain attitude reports for analysis and animation.
Parameter Details Description
Magnets Magnet Material Alnico-5
Total Volume 0.59 cm3
Total MagneticDipole
0.5869 Am2
(calculated)North Pole CubeSat -Z face
HysteresisMaterial
Type HyMu80
Total Volume 0.15 cm3 (0.075 cm3 per axis)
Coercivity 1.59 A/m
Saturation 0.73 Tesla
Remanence 0.35 Tesla
OrbitParameters
Orbit Altitude 700 km
Inclination 98˚
Design Summary
