Gyro-Control of a Solar Sailing Satellite by Hendrik W. Jordaan Willem H. Steyn Electronic Systems Laboratory Department of Electrical & Electronic Engineering Stellenbosch University January 20, 2017 International Solar Sailing Symposium Background Attitude Control Solar sailing Gyro-Control Conclusion
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Gyro-Control of a Solar Sailing Satellite · 2017-03-01 · Gyro-Control of a Solar Sailing Satellite by Hendrik W. Jordaan Willem H. Steyn Electronic Systems Laboratory Department
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Gyro-Control of a Solar Sailing Satellite
by
Hendrik W. Jordaan
Willem H. Steyn
Electronic Systems Laboratory
Department of Electrical & Electronic Engineering
Stellenbosch University
January 20, 2017
International Solar Sailing Symposium
Background
Attitude ControlSolar sailing
Gyro-Control
Conclusion
Situated about 30 minutes
away from Cape-Town,
South-Africa
Stellenbosch
International Solar Sailing Symposium
Background
Attitude ControlSolar sailing
Gyro-Control
Conclusion
History with microsatellites,
SunSat, SunSpace,
SumbandilaSat
Current main focus is on ADCS
research
Develop ADCS CubeSat
components which is sold
under CubeSpace brand
Also involved in a number of
interesting international projects
Stellenbosch University
International Solar Sailing Symposium
Background
Attitude ControlSolar sailing
Gyro-Control
Conclusion
• Current solar sailing missions main payload is the solar sail
• Future missions will have other science payloads e.g.
image payloads
• Main specification driver for attitude control is mission
payload
• Attitude control requirements for solar sailing is low, only
slow manoeuvres and rough attitude stability relative to a
sun angle.
• High sampling and long exposure payloads very stringent
attitude requirements
Attitude Requirements
International Solar Sailing Symposium
Background
Attitude ControlSolar sailing
Gyro-Control
Conclusion
• Largest difference between a solar sail and standard
spacecraft is the large MoI, which is obtained when
deploying a large space structure.
• When comparing the MoI of a 80m2 and 100m2 square sail
there is a 43.9% increase in the MoI with less than a meter
increase in boom length.
• The attitude control actuator specifications should increase
• This is dependent on the sail/spacecraft MoI ratio
• Ratio of the sail MoI relative to the entire spacecraft MoI
Standard Satellite vs Solar Sail Satellite
Parameter 80m2 Sail 100m2 Sail
Boom length 6.325m 7.071m
MoI Ixx=Izz 10.149kg.m2 14.607kg.m2
MoI Iyy 20.299kg.m2 29.213kg.m2
International Solar Sailing Symposium
Background
Attitude ControlSolar sailing
Gyro-Control
Conclusion
• The sail/spacecraft MoI ratio is determined simply by λ =max(𝚲) with 𝚲 = 𝑰𝑆/𝑰 where 𝑰𝑆 the MoI of the sail and 𝑰 is
MoI of the entire spacecraft.
• Small λ indicates rotational dynamics of spacecraft is
dominant
• Larger λ indicates that the dynamics are greatly influenced
by the sail
• MoI will greatly influence the attitude performance either
increase in sail size or vibration of non-rigid elements
• Some control attitude control methods will greatly influence
this ratio and thus less suitable to scale to larger solar sails.
• Manoeuvres are limited by actuator specifications and the
non-rigid dynamics of the sail
Standard Satellite vs Solar Sail Satellite
International Solar Sailing Symposium
Background
Attitude ControlSolar sailing
Gyro-Control
Conclusion
• Current attitude control methods can be separated into two
categories:
• Active methods
• Thrusters (gas and electric)
• Standard magnetorquer rods
• Reaction and momentum wheels
• Solar thrust methods
• Changing CoM
• Translation stage
• Control boom
• Mass-balasts
• Changing CoP
• Reflective changes
• Control vanes
• Sail shape changes
• Review by Fu et al. 2016
Current attitude control methods
International Solar Sailing Symposium
Background
Attitude ControlSolar sailing
Gyro-Control
Conclusion
• Spinning sail has a number of advantages above stabilised
sail
• Unsymmetrical solar thrust averaged to spin vector
• Centrifugal force produce internal force
• Major drawbacks are
• Satellite bus is rotating, limits mission payload