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- Reaction_wheel abstract "A reaction wheel (RW) is a type of flywheel used primarily by spacecraft for attitude control without using fuel for rockets or other reaction devices. They are particularly useful when the spacecraft must be rotated by very small amounts, such as keeping a telescope pointed at a star. They may also reduce the mass fraction needed for fuel. This is accomplished by equipping the spacecraft with an electric motor attached to a flywheel which, when its rotation speed is changed, causes the spacecraft to begin to counter-rotate proportionately through conservation of angular momentum. Reaction wheels can only rotate a spacecraft around its center of mass (see torque); they are not capable of moving the spacecraft from one place to another (see translational force). Reaction wheels work around a nominal zero rotation speed. However, external torques on the spacecraft may require a gradual buildup of reaction wheel rotation speed to maintain the spacecraft in a fixed orientation.A reaction wheel is sometimes operated as (and referred to as) a momentum wheel, by operating it at a constant (or near-constant) rotation speed, in order to imbue a satellite with a large amount of stored angular momentum. Doing so alters the spacecraft's rotational dynamics so that disturbance torques perpendicular to one axis of the satellite (the axis parallel to the wheel's spin axis) do not result directly in spacecraft angular motion about the same axis as the disturbance torque; instead, they result in (generally smaller) angular motion (precession) of that spacecraft axis about a perpendicular axis. This has the effect of tending to stabilize that spacecraft axis to point in a nearly-fixed direction, allowing for a less-complicated attitude control system. Satellites using this \"momentum-bias\" stabilization approach include SCISAT-1; by orienting the momentum wheel's axis to be parallel to the orbit-normal vector, this satellite is in a \"pitch momentum bias\" configuration.A control moment gyroscope (CMG) is a related but different type of attitude actuator, generally consisting of a momentum wheel mounted in a one-axis or two-axis gimbal. When mounted to a rigid spacecraft, applying a constant torque to the wheel using one of the gimbal motors causes the spacecraft to develop a constant angular velocity about a perpendicular axis, thus allowing control of the spacecraft's pointing direction. CMGs are generally able to produce larger sustained torques than RWs with less motor heating, and are preferentially used in larger and/or more-agile spacecraft, including Skylab and the International Space Station.".
- Reaction_wheel thumbnail Reaction_wheel00.jpg?width=300.
- Reaction_wheel wikiPageExternalLink viewcontent.cgi?filename=0&article=1496&context=smallsat&type=additional.
- Reaction_wheel wikiPageID "89484".
- Reaction_wheel wikiPageLength "11878".
- Reaction_wheel wikiPageOutDegree "39".
- Reaction_wheel wikiPageRevisionID "705166630".
- Reaction_wheel wikiPageWikiLink Angular_momentum.
- Reaction_wheel wikiPageWikiLink Attitude_control.
- Reaction_wheel wikiPageWikiLink Category:Gyroscopes.
- Reaction_wheel wikiPageWikiLink Category:Spacecraft_attitude_control.
- Reaction_wheel wikiPageWikiLink Category:Spacecraft_propulsion.
- Reaction_wheel wikiPageWikiLink Control_moment_gyroscope.
- Reaction_wheel wikiPageWikiLink Electric_motor.
- Reaction_wheel wikiPageWikiLink Exoplanet.
- Reaction_wheel wikiPageWikiLink Flywheel.
- Reaction_wheel wikiPageWikiLink Gimbal.
- Reaction_wheel wikiPageWikiLink Hayabusa.
- Reaction_wheel wikiPageWikiLink Hubble_Space_Telescope.
- Reaction_wheel wikiPageWikiLink International_Space_Station.
- Reaction_wheel wikiPageWikiLink Ion_thruster.
- Reaction_wheel wikiPageWikiLink Kepler_(spacecraft).
- Reaction_wheel wikiPageWikiLink Magnetorquer.
- Reaction_wheel wikiPageWikiLink Materials_for_use_in_vacuum.
- Reaction_wheel wikiPageWikiLink Monopropellant_rocket.
- Reaction_wheel wikiPageWikiLink Payload_fraction.
- Reaction_wheel wikiPageWikiLink Precession.
- Reaction_wheel wikiPageWikiLink ROSAT.
- Reaction_wheel wikiPageWikiLink Reaction_control_system.
- Reaction_wheel wikiPageWikiLink Rocket_engine.
- Reaction_wheel wikiPageWikiLink SCISAT-1.
- Reaction_wheel wikiPageWikiLink STS-109.
- Reaction_wheel wikiPageWikiLink STS-82.
- Reaction_wheel wikiPageWikiLink Skylab.
- Reaction_wheel wikiPageWikiLink Solar_sail.
- Reaction_wheel wikiPageWikiLink Space_Shuttle_Columbia.
- Reaction_wheel wikiPageWikiLink Spacecraft.
- Reaction_wheel wikiPageWikiLink Spacecraft_propulsion.
- Reaction_wheel wikiPageWikiLink Torque.
- Reaction_wheel wikiPageWikiLink Translation_(geometry).
- Reaction_wheel wikiPageWikiLink UTC_Aerospace_Systems.
- Reaction_wheel wikiPageWikiLink Vernier_thruster.
- Reaction_wheel wikiPageWikiLink File:Reaction_wheel00.jpg.
- Reaction_wheel wikiPageWikiLink File:Reaction_wheel02.jpg.
- Reaction_wheel wikiPageWikiLinkText "Momentum-wheel".
- Reaction_wheel wikiPageWikiLinkText "Reaction wheel".
- Reaction_wheel wikiPageWikiLinkText "momentum wheel".
- Reaction_wheel wikiPageWikiLinkText "momentum wheels".
- Reaction_wheel wikiPageWikiLinkText "reaction wheel".
- Reaction_wheel wikiPageWikiLinkText "reaction/momentum wheels".
- Reaction_wheel wikiPageUsesTemplate Template:Citation_needed.
- Reaction_wheel wikiPageUsesTemplate Template:Cite_web.
- Reaction_wheel wikiPageUsesTemplate Template:Commons_category.
- Reaction_wheel wikiPageUsesTemplate Template:Reflist.
- Reaction_wheel wikiPageUsesTemplate Template:s.
- Reaction_wheel subject Category:Gyroscopes.
- Reaction_wheel subject Category:Spacecraft_attitude_control.
- Reaction_wheel subject Category:Spacecraft_propulsion.
- Reaction_wheel hypernym Flywheel.
- Reaction_wheel type Instrument.
- Reaction_wheel type Astrodynamic.
- Reaction_wheel type Concept.
- Reaction_wheel type Gyroscope.
- Reaction_wheel type Instrument.
- Reaction_wheel type Machine.
- Reaction_wheel type Redirect.
- Reaction_wheel type Technology.
- Reaction_wheel comment "A reaction wheel (RW) is a type of flywheel used primarily by spacecraft for attitude control without using fuel for rockets or other reaction devices. They are particularly useful when the spacecraft must be rotated by very small amounts, such as keeping a telescope pointed at a star. They may also reduce the mass fraction needed for fuel.".
- Reaction_wheel label "Reaction wheel".
- Reaction_wheel sameAs Q2457049.
- Reaction_wheel sameAs Reaktionsrad.
- Reaction_wheel sameAs Rueda_de_reacción.
- Reaction_wheel sameAs Roue_de_réaction.
- Reaction_wheel sameAs Roda_reaksi.
- Reaction_wheel sameAs リアクションホイール.
- Reaction_wheel sameAs Koło_reakcyjne.
- Reaction_wheel sameAs m.0m9zd.
- Reaction_wheel sameAs Bánh_đà_phản_lực.
- Reaction_wheel sameAs Q2457049.
- Reaction_wheel wasDerivedFrom Reaction_wheel?oldid=705166630.
- Reaction_wheel depiction Reaction_wheel00.jpg.
- Reaction_wheel isPrimaryTopicOf Reaction_wheel.