The Canfield joint is a mechanism that allows for full hemispherical motion from whatever connects to it. Invented by Dr. Stephen Canfield of the Tennessee Tech University, this joint was developed specifically for spacecraft thrusters and solar panels. Its gimbal mount simplifies the roll manoeuvre performed when the space shuttle launches and allows for greater overall manoeuvrability from the Reaction control system.Unlike other joints,which can only transmit rotational motion up to a constant 70° (not 0 ° to 70°), this joint can transmit rotary motion from 0° and in increments one 1° to 90°. Also this joint has higher stability due to its unique cage-like design.By making use of appropriate actuators (hydraulic/pneumatic),the joint can be moved with surprising speed and accuracy.
When applied to solar panels, the Canfield joint tracks the Sun more of the time and will not tangle the power cords attached to them. This is especially valuable to space flight when the spacecraft is performing complicated manoeuvres. Its applications will be incorporated into the Constellation Program as a key element.
Advantages Over Fixed Thrusters 
- Fewer parts resulting in fewer mechanical failures and less weight
- Twelve fewer thrusters
- Simplifies movement for roll maneuver
- Allows greater maneuverability