AOCS_A4

Reaction Wheels

Jean-Matthieu COUSIN

jean-matthieu.cousin@insa-lyon.fr

National Institute of Applied Sciences (INSA)

Lyon, FRANCE

European Student Moon Orbiter - Phase B workplan

Actual Design Workplan

Simulation

Conclusion

AOCS_A4 : Reaction wheels

Outline :

European Student Moon Orbiter - Phase B workplan

Dynacon Micro Wheel 1000

What do we have to do now ?

AOCS_A4 : Reaction wheels

Actual Design

Workplan

Simulation

Conclusion

European Student Moon Orbiter - Phase B workplan

Spacecraft : need different

attitudes

AOCS :

Sensors

software

MRW

AOCS_A4 : Reaction wheels

Performance Requirements : Assure pointing accuracy during Imaging mode (NAC) Maintain attitude for communications with lunette during

subsatellite mode without any help from the thrusters

Lifetime Requirements : Required delta-V momentum offloading should not

exceed the propellant mass budget of the Attitude Control Thrusters for a 10 months mission.

Configuration Requirements : Provide a full 3-axis control Minimize power drain while maintaining redundancy Include angular rate and temperature sensors Allow ease of integration in the Spacecraft

European Student Moon Orbiter - Phase B workplan

Actual Design

Workplan

Simulation

Conclusion

Workplan

Actual Design

AOCS_A4 : Reaction wheels

Simulation

Actuators selected : with a worksheet validation

Dynacon MicroWheel 1000

• Moment storage capacity :1.1 N.m.s

• Power consumption : 10 W max (9W +1W)

• Speed range : +/- 10,000 RPM

• Max Torque : 30 mN.m

• Size : 129x 129x 88,5 mm

• Mass : 1.3 kg • Include angular rate and temperature sensors

Conclusion

European Student Moon Orbiter - Phase B workplan

WARNING!!!Is it sufficient with the current configuration?

Actual Design

Workplan

AOCS_A4 : Reaction wheels

Simulation

Conclusion

European Student Moon Orbiter - Phase B workplan

Objective :

Update the Excel WorksheetAnd check the MRW1000 with the current configuration.

Requirements :

SPEC from AOCS_A1and the former requirements

Tools :

EXCEL

Comments : Try with the STRU team to perfectionate the Worksheet to add the new inertial data more easily.

Actual Design

Workplan

AOCS_A4 : Reaction wheels

Simulation

Conclusion

European Student Moon Orbiter - Phase B workplan

Objective :

Requirements :

Tools :

Comments :

Put forward a partnership with INSA and build our own Wheels.

We need to increase our team, about to be highly capable in different subjects as electronic, software…

SPEC from AOCS_A1and the former requirementsEPS requirements

…

Actual Design

Workplan

AOCS_A4 : Reaction wheels

Simulation

Conclusion

European Student Moon Orbiter - Phase B workplan

Objective :Decide which kind of electronic components we need, which kind of interfaces…Requirements :

Tools :

Comments :

SPEC from AOCS_A1and the former requirementsOBDH and EPS requirements

It’s a major problem that we have to resolve. (for OBDH and EPS team)

…

Actual Design

Workplan

AOCS_A4 : Reaction wheels

Simulation

Conclusion

European Student Moon Orbiter - Phase B workplan

Objective :

Convert our model on Catia file

Requirements :

Tools :

Catia

Comments :

Should we use a specific version of Catia?

Requirements

Validation

AOCS_A4 : Reaction wheels

Conclusion

Actual Design

Performance requirements during Imaging mode :

Nadir pointing mode : countering disturbances while maintaining pointing accuracy

Solar Radiation Pressure Torque : 5.10-7 N.mGravity Gradient Torque : 7.10-7 N.m (worst case)

Max torque available : 3.10-2 N.mMomentum storage capacity allow us to

maintain attitude during 24 hours before using thrusters to off-load the wheels

European Student Moon Orbiter - Phase A review

Actual Design

Workplan

AOCS_A4 : Reaction wheels

Simulation

Conclusion

European Student Moon Orbiter - Phase B workplan

Objective :

Requirements :

Tools :

Comments :

Determine if a software is required or not? To convert inputs in voltage or intensity

OBDH requirements

Requirements

Validation

AOCS_A4 : Reaction wheels

Conclusion

Actual Design

Performance requirements during Imaging mode :

Nadir pointing mode : countering disturbances while maintaining pointing accuracy

Solar Radiation Pressure Torque : 5.10-7 N.mGravity Gradient Torque : 7.10-7 N.m (worst case)

Max torque available : 3.10-2 N.mMomentum storage capacity allow us to

maintain attitude during 24 hours before using thrusters to off-load the wheels

European Student Moon Orbiter - Phase A review

Actual Design

Workplan

AOCS_A4 : Reaction wheels

Simulation

Conclusion

European Student Moon Orbiter - Phase B workplan

Objective :

Requirements :

Tools :

Comments :

Make our simulation.

Simulation team requirements

Matlab, Simulink

We have to talk about the simulation with the team in charge of it.

Requirements

Validation

AOCS_A4 : Reaction wheels

Conclusion

Actual Design

Performance requirements during Imaging mode :

Nadir pointing mode : countering disturbances while maintaining pointing accuracy

Solar Radiation Pressure Torque : 5.10-7 N.mGravity Gradient Torque : 7.10-7 N.m (worst case)

Max torque available : 3.10-2 N.mMomentum storage capacity allow us to

maintain attitude during 24 hours before using thrusters to off-load the wheels

European Student Moon Orbiter - Phase A review

Actual Design

Simulation

AOCS_A4 : Reaction wheels

Workplan

Conclusion

European Student Moon Orbiter - Phase B workplan

Simulation :

Inputs :

• Torques we have to apply for each wheels.• Information from the ground station : unload

Outputs :

• Temperature (so we need a model to simulate the friction).

• The speed of each wheel

• The power consumption ?

Requirements

Validation

AOCS_A4 : Reaction wheels

Conclusion

Actual Design

Performance requirements during Imaging mode :

Nadir pointing mode : countering disturbances while maintaining pointing accuracy

Solar Radiation Pressure Torque : 5.10-7 N.mGravity Gradient Torque : 7.10-7 N.m (worst case)

Max torque available : 3.10-2 N.mMomentum storage capacity allow us to

maintain attitude during 24 hours before using thrusters to off-load the wheels

European Student Moon Orbiter - Phase A review

Actual Design

Simulation

AOCS_A4 : Reaction wheels

Workplan

Conclusion

European Student Moon Orbiter - Phase B workplan

Simulation :

Structure : Nominal Mode Torque

Acceleration required

Rotation speed

Required speed

Power consumptionTemperature

New rotation speed

Intensity required

STEP ?Every minutes? + - ?

Requirements

Validation

AOCS_A4 : Reaction wheels

Conclusion

Actual Design

Performance requirements during Imaging mode :

Nadir pointing mode : countering disturbances while maintaining pointing accuracy

Solar Radiation Pressure Torque : 5.10-7 N.mGravity Gradient Torque : 7.10-7 N.m (worst case)

Max torque available : 3.10-2 N.mMomentum storage capacity allow us to

maintain attitude during 24 hours before using thrusters to off-load the wheels

European Student Moon Orbiter - Phase A review

Actual Design

Simulation

AOCS_A4 : Reaction wheels

Workplan

Conclusion

European Student Moon Orbiter - Phase B workplan

Simulation :

Structure : unload Mode

Order from ground : unload

Rotation speed required.

Intensity required

New rotation speed

Requirements

AOCS_A4 : Reaction wheels

Actual Design

Conclusion

Validations

European Student Moon Orbiter - Phase A review

Answering Questions…

Thank you for your attention