ADCS/GNC Flashcards
What does the ACDS do?
keeps the spacecraft accurately and precisely pointed in the right direction
attitude determination control system
What reference frame is used in relation to the spacecraft in space?
ECI - earth centered inertial frame
z = north pole
x = vernal equinox
What reference frame is used on spacecraft?
LVLH/ORB - local vertical, local horizon / orbiting frame
z axis = towards center of earth
y axis = perpendicular to orbital plane
x axis = tangent to plane / orbit
What is the control system setup?
desired attitude controller actuator dynamics sensors
List some types of sensors
horizon/earth sun sensors star tracker magnetometer gyros GPS accelerometer
What are some common actuators?
magnetotorquers
control gyros
thrusters
reaction wheel
Environment disturbances are caused by?
solar radiation pressure
atmospheric drag
gravity gradient
magnetic field torwue
What are ways of passive stabilization?
gravity gradient
spin stabilizers
dampers
ACDS are often…?
massive and power consuming and often drive overall spacecraft design.
ACDS is the most…?
challenging spacecraft subsystem to design and test
What is the ACDS composed of?
sensors, actuators, attitude control algorithms
What is the difference between control and determination?
determination - how well you know where you are pointed
control - how well you can point in the right direction and get there
