The Canfield joint is a pointing mechanism that allows for full hemispherical motion from whatever connects to it. Essentially it is a 3

degree of freedom In many scientific fields, the degrees of freedom of a system is the number of parameters of the system that may vary independently. For example, a point in the plane has two degrees of freedom for translation: its two coordinates; a non-infinites ...

derivative of the

Stewart platform A Stewart platform is a type of parallel manipulator that has six prismatic joint, prismatic actuators, commonly hydraulic jacks or electric linear actuators, attached in pairs to three positions on the platform's baseplate, crossing over to thr ...

, which has 6 degrees of freedom. Invented by Stephen Canfield of Tennessee Tech University, this joint was developed specifically for spacecraft thrusters and

solar panel A solar panel is a device that converts sunlight into electricity by using photovoltaic (PV) cells. PV cells are made of materials that produce excited electrons when exposed to light. These electrons flow through a circuit and produce direct ...

s. Its

gimbal A gimbal is a pivoted support that permits rotation of an object about an axis. A set of three gimbals, one mounted on the other with orthogonal pivot axes, may be used to allow an object mounted on the innermost gimbal to remain independent of ...

mount simplifies the roll program performed when the

Space Shuttle The Space Shuttle is a retired, partially reusable launch system, reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. ...

launches and allows for greater overall manoeuvrability from the

reaction control system A reaction control system (RCS) is a spacecraft system that uses Thrusters (spacecraft), thrusters to provide Spacecraft attitude control, attitude control and translation (physics), translation. Alternatively, reaction wheels can be used for at ...

. 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°. This joint also has higher stability due to its unique cage-like design. When applied to solar panels, the Canfield joint tracks the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

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 application was expected to be incorporated into the now-defunct

Constellation Program The Constellation program (abbreviated CxP) was a crewed spaceflight program developed by NASA, the space agency of the United States, from 2005 to 2009. The major goals of the program were "completion of the International Space Station" and a " ...

as a key element.Tech Times by Tennessee Tech University “NASA proposes using Canfield invention on latest space craft”

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

References

{{reflist Spacecraft components Mechanisms (engineering)