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Actuators

Actuators​

Actuators are used to orient the spacecraft based on the attitude control algorithm or to provide thrust using a thrust control algorithm. Each algorithm is assigned specific actuators by the user. Currently, the available actuators are Reaction Wheels, Magnetorquers, and Thrusters.

Reaction Wheels​

Reaction wheels exert a torque on the spacecraft by changing the angular velocity of the wheel. In addition to providing a name and hardware ratings, you will also provide a body frame vector that the defines the direction of the produced torque. You must also choose a source of power, either a Power Processor or Bus Regulator.

Finally, specify the reaction wheel’s inertia, rated angular momentum (maximum angular momentum storage), rated torque (maximum instantaneous torque), and efficiency (a measure of how much power is lost to heat).

Magnetorquers​

Magnetorquers exert a torque on the spacecraft via an interaction between the magnetorquer's magnetic moment and the Earth's magnetic field.

Specify a name, hardware properties, and a power source, as with a Reaction Wheel. Next, provide the direction of the magnetic moment. The produced torque will always be orthogonal to this vector. Finally, specify the device’s maximum rated magnetic moment and the power draw at the maximum. The control algorithm uses Pulse-Width Modulation (PWM) to drive a variable torque.

Thrusters​

Thrusters exert force and torque on the spacecraft, as determined by the thrust control algorithm and placement of the thrusters.

Start creating a thruster by specifying the minimum and maximum thrust as well as the specific impulse (Isp), given by nozzle exhaust velocity divided by the standard gravitational acceleration.

Specify the location of the thruster by entering its Cartesian coordinates in the body frame and select its orientation using a Body Frame Vector. The orientation is the direction of the exhaust, so the direction of thrust will be anti-parallel to this vector.

Select a Fuel Reservoir from which the thruster will draw propellant and choose a power source which will supply the thruster with any dynamic power requirements (currently not implemented, but please select a power source anyway).