
	Where results make sense

Topic: Reaction wheel

Related Topics

Clementine mission

Luna 23

Lunokhod 2

Luna 22

Luna 24

Mass concentration

Luna program

	Spacecraft attitude control system with reaction wheel bearing protection - Patent 5248118 (Site not responding. Last check: 2007-10-09)
		In general, "reaction" wheels provide torques by accelerations which cause the wheel to spin in either direction, passing through zero angular velocity at some times, whereas momentum wheels are "biased" to a relatively high angular velocity, and are accelerated and decelerated, as required, while maintaining rotation in a single direction.
		The momentum wheel has the advantage that the wheel bearings tend to be more reliable than the bearings in a reaction wheel, which is believed to result from maintenance of a continuous film of lubricant on the bearing surfaces by the rapid motion of the bearing.
		The wheel speed signals are applied to a momentum error signal generator 60, which converts the wheel speed into an equivalent momentum by multiplying the wheel speed by the estimated inertia of the wheel.
	www.freepatentsonline.com /5248118.html (4896 words)

	Reaction wheel fricton compensation using dither - Patent 5020745
		Consequently, at the moment when reaction wheel rotation in the opposite direction begins, the error signal tends to be larger than necessary, and as a result the torque command signal is excessive.
		A controllable torquing arrangement is coupled to the wheel for applying torque to the wheel in response to a torque command signal for accelerating or decelerating the reaction wheel and thereby transferring momentum to the spacecraft body.
		If the absolute value of the wheel speed is greater than the threshold, the logic flows from decision block 804 by the NO path, and arrives at a block 806 which disables the dither generator (a part of block 62, not separately illustrated), whether or not it was previously enabled.
	www.freepatentsonline.com /5020745.html (3229 words)

	FUSE Reaction Wheel FAQ Page
		On December 10, 2001, the FUSE satellite suspended science operations temporarily because of problems with the reaction wheels on the spacecraft.
		Reaction wheels, or momentum wheels as they are sometimes called, are devices used on many satellites to hold the satellite steady (when desired) or move the pointing direction from one place to another (a procedure called `slewing').
		A reaction wheel is basically just a spinning flywheel mounted on a central bearing whose rate of rotation can be adjusted as necessary by an electric motor to apply a force and move the spacecraft.
	fuse.pha.jhu.edu /educ/RW_FAQ.html (656 words)

	Search Encyclopedia.com (Site not responding. Last check: 2007-10-09)
		catalyst catalyst, substance that can cause a change in the rate of a chemical reaction without itself being consumed in the reaction; the changing of the reaction rate by use of a catalyst is called catalysis.
		carriage carriage, wheeled vehicle, in modern usage restricted to passenger vehicles that are drawn or pushed, especially by animals.
		neutralization neutralization, chemical reaction, according to the Arrhenius theory of acids and bases, in which a water solution of acid is mixed with a water solution of base to form a salt and water; this reaction is complete only if the resulting solution has neither acidic nor basic properties.
	www.encyclopedia.com /search.asp?target=reaction+wheel&rc=10&fh=6&fr=31 (434 words)

	Encyclopedia: Reaction wheel
		A momentum wheel is a type of flywheel used primarily by spacecraft to change their angular momentum without using fuel for rockets or other reaction devices.
		Typically a spacecraft will have several momentum wheels oriented along orthogonal axes, and when it wishes to change its rotation along those axes it will increase or decrease the spin of the momentum wheels in the opposite direction.
		Since the momentum wheel is a small fraction of the spacecraft's total mass, easily-measurable changes in its speed provide very precise changes in angle.
	www.nationmaster.com /encyclopedia/Reaction-wheel (347 words)

	NASA GODDARD SPACE FLIGHT CENTER OPTIMIZES SATELLITE REACTION WHEEL WITH RANDOM VIBRATION SOFTWARE
		The redesigned reaction wheels were launched successfully on the Transition Region and Coronal Explorer (TRACE, shown left) in April 1998, a satellite mission that is studying the sun's coronal region.
		The new reaction wheels were launched successfully on the Transition Region and Coronal Explorer (TRACE) in April 1998, a satellite mission that is studying the sun's coronal region, and are scheduled to be used on two upcoming space expeditions.
		The redesigned reaction wheels were successfully launched with the TRACE satellite in April 1998 and are scheduled to operate on the Submillimeter Wave Astronomy Satellite (SWAS) leaving Earth in December 1998 and the Wide Field Infrared Explorer (WIRE) satellite launching in April 1999.
	www.algor.com /news_pub/cust_app/goddard/goddard.asp (850 words)

	Information on Reaction wheel
		[1913 Webster] Reaction is always equal and opposite to action, that is to say, the actions of two bodies upon each other are always equal and in opposite directions.
		The reaction may be primarily mental (" a reaction of surprise") but is usually manifested by some activity.
		Reaction wheel (Mech.), a water wheel driven by the reaction of water, usually one in which the water, entering it centrally, escapes at its periphery in a direction opposed to that of its motion by orifices at right angles, or inclined, to its radii.
	www.wkonline.com /d/Reaction_wheel.html (370 words)

	Pre-bias scheme for roll momentum unloads on pitch momentum bias/yaw reaction wheel spacecraft - US Patent 6439509 (Site not responding. Last check: 2007-10-09)
		In dealing with short-term transients due to disturbances such as roll momentum unloads, currently the spacecraft is biased in roll angle, approximately 50% of the magnitude, in the opposite direction of the expected transient.
		Each system involves orientation sensing components and means for adjusting the orientation of the craft including magnetic torquers, momentum wheels, and thrusters, which alter and unload unwanted momentum resulting from imposed forces from solar torque, thruster firing, fuel shift, and such.
		The present invention is directed to such a system for controlling and reducing short-term transients caused by disturbances, such as roll momentum unloads, and utilizes the spacecraft nutation damper, particularly the nutation compensator, in achieving this end.
	www.patentstorm.us /patents/6439509.html (1606 words)

	OSV - Outward-Flow Reaction Wheel (Site not responding. Last check: 2007-10-09)
		The reaction wheel is made of a hollow iron disk with a large hole on one side to allow pressurized water in from a penstock,and six angled holes on the rim to allow water to exit.
		The force of water squirting through these six angled jets causes the wheel to turn in reaction to the force of the exiting water.
		The reaction wheel, in some ways the predecessor of the modern turbine, operates on water pressure.
	www.osv.org /education/WaterPower/Reaction.html (215 words)

	Basics of Space Flight Section II. Space Flight Projects
		Another method for achieving three-axis stabilization is to use electrically-powered reaction wheels, also called momentum wheels.
		Reaction wheels provide a much steadier spacecraft from which to make observations, but they add mass to the spacecraft, they have a limited mechanical lifetime, and they require frequent momentum desaturation maneuvers, which can perturb navigation solutions because of accelerations imparted by their use of thrusters.
		Reaction wheels are fairly massive attitude control devices at the output of AACS computers.
	www2.jpl.nasa.gov /basics/bsf11-2.html (2509 words)

	Livid's Lividict - reaction wheel (Site not responding. Last check: 2007-10-09)
		Reaction is always equal and opposite to action, that is to say, the actions of two bodies upon each other are always equal and in opposite directions.
		The new king had, at the very moment at which his fame and fortune reached the highest point, predicted the coming reaction.
		{Reaction time} (Physiol.), in nerve physiology, the interval between the application of a stimulus to an end organ of sense and the reaction or resulting movement; -- called also {physiological time}.
	livid.3322.org /lookup/reaction%20wheel.html (812 words)

	Re: Dec EMini,Whats a Square reaction/wheel (Site not responding. Last check: 2007-10-09)
		Wheel Study -- Monday, 6 December 2004, at 12:46 p.m.
		Wheel Study -- Monday, 6 December 2004, at 1:16 p.m.
		Wheel Study -- Monday, 6 December 2004, at 1:31 p.m.
	tfc-charts2.w2d.com /forum/index.cgi/noframes/read/317286 (422 words)

	Reaction to Cassini's reaction wheel glitch -- December 26th, 2000
		You need at least three reaction wheels because the spacecraft needs to be maneuvered in three dimensions in space, and each one can only re-orient the space probe along one axis.
		Four is the normal number, which gives the probe one spare reaction wheel which can partially substitute for any of the others, in conjunction with the other two that continue to work.
		Observations were halted Wednesday after one of the spacecraft’s four “reaction wheels” experienced problems, causing Cassini to switch to a different maneuvering system..
	www.animatedsoftware.com /cassini/cass2001/smashca.htm (963 words)

	Mars Global Surveyor Mission Status (Site not responding. Last check: 2007-10-09)
		Engineering data from the spacecraft indicate that an electrical short led to the automatic shutdown of the X-axis reaction wheel on Jan. 18.
		Spacecraft orientation is stabilized by the rotation of three such wheels (X,Y and Z) during normal operations.
		Subsequent attempts to restart the X-axis reaction wheel on Jan. 24 lead mission engineers to believe that a short circuit caused the reaction wheel subsystem's 7 amp fuse to become permanently open, permanently disabling the reaction wheel.
	mars.jpl.nasa.gov /mgs/status/reports/26-jan-2001.html (303 words)

	Reaction/Momentum Wheel
		Being a big wheel in spacecraft lingo may be detrimental if you are trying to stay competitive in the explosive world of small satellite building.
		The wheel is unique in its small size, extremely low residual imbalance, and large, highly controllable torque.
		This wheel is unique in that it features a large, highly controllable torque in a small package with low power and an extremely low residual imbalance.
	www.sti.nasa.gov /tto/spinoff1997/t3.html (568 words)

	ARRLWeb: AO-40 Attitude Control System Appears Functional
		The momentum wheel system in AO-40 is an experimental version developed by Phase 3D Project Leader Karl Meinzer, DJ4ZC, of the University of Marburg, who came up with a system using frictionless magnetic bearings with two active controlled axes and one passive axis.
		Correct operation of the momentum wheels is considered essential to solar panel deployment.
		Earlier this year, Guelzow had said he would "be surprised" if the momentum wheels work okay after what he called "the possible destruction in the inner core of the spacecraft" resulting from an onboard malfunction last December involving the 400-newton propulsion system.
	www.arrl.org /news/stories/2001/08/17/3 (564 words)

	Momentum wheel : Reaction wheel
		terms defined : Momentum wheel : Reaction wheel
		All is still licensed under the GNU FDL.
		Half-past one, The street lamp muttered, "Regard that woman Which opens on her like a grin.
	www.termsdefined.net /re/reaction-wheel.html (570 words)

	reaction wheel
		Typically, three reaction wheels are mounted with their axes pointing in mutually perpendicular directions.
		To rotate the spacecraft in one direction, the appropriate reaction wheel is spun in the opposite direction.
		To rotate the vehicle back, the wheel is slowed down.
	www.daviddarling.info /encyclopedia/R/reaction_wheel.html (136 words)

	Re: GX-3: Reaction Wheel CS (RWCS) (Site not responding. Last check: 2007-10-09)
		However -- what if each of the wheels had the batteries that would act as their primary power source distributed about the circumference of the wheel.
		This seems really really really cool to me. Reaction wheels that contain their own motive power.
		In addition, you would obviously provide the ability to cross-connect the power sources such that the main battery bank could power either or both reaction wheels and the RW batteries could be used to power the main instruments.
	uplink.space.com /printthread.php?Cat=&Board=businesstech&main=208570&type=post (416 words)

	Thin Film with Momentum Wheel (Site not responding. Last check: 2007-10-09)
		This page shows a mockup of satellite, which is thin film with reaction wheel type.
		Middle part panels are removed and you can see a reaction wheel.
		Hanging the satellite by wires and the reaction wheel makes the satellite rotate the opposite way.
	www.space.t.u-tokyo.ac.jp /cansat/design/model.html (62 words)

	Reaction wheel system with vernier control rotor
		A reaction wheel system is рrоvided thаt comprises least twо rotors.
		The vernier control rotor hаs an inertiaI mass thаt is less thаn the inertiaI mass of the main rotor, and rotаtes separately of the main rotor.
		Because the vernier control rotor саn be rоtated separately frоm the main rotor, it саn be used to considerably better the performаnce of the reaction wheel system.
	www.patentalert.com /docs/000/z00097075.shtml (328 words)

	Bibliographie des DLR (LIDO) (Site not responding. Last check: 2007-10-09)
		Reaction wheels (RW) nowadays are broadly used in small satellites’ attitude control systems (ACS).
		The new reaction wheels were jointly developed by DLR and "Astro- und Feinwerktechnik Adlershof GmbH".
		The subject dealt with in this paper is the description of tests done to verify the RW parameters and to derive a model for real time and software in the loop simulations.
	www2.dlr.de /lido/WP/2001/1818372001.html (203 words)

	FUSE Mission Status
		We have had some difficulties earlier with the reaction wheels (see previous Status reports #42, #43, and #36), but have been able to fix these earlier problems with minimal lost time.
		On Monday, Dec. 10th, a second reaction wheel shut down, leaving us with only two operational reaction wheels, and thus no control in one axis of motion on the spacecraft.
		In the event that one of the two errant reaction wheels cannot be restarted, we are already assessing the options for controlling the attitude with other mechanisms on the spacecraft.
	fuse.pha.jhu.edu /facts/miss_rep52.html (517 words)

	Basics of Space Flight Section II. Space Flight Projects
		These may be used to provide the large torques necessary to maintain stability during a solid rocket motor burn, or they may be the only rockets used for orbit insertion.
		The 1-N thrusters were used for momentum wheel desaturation and other small maneuvers.
		The act of ejecting mass at extremely high speed provides the classical action for which the reaction is spacecraft acceleration in the opposite direction.
	www2.jpl.nasa.gov /basics/bsf11-4.html (1989 words)

	Chain Reaction wheels? & MTB wheel wanted
		I now know Chain Reaction's postage is free even for a wheel.
		But their wheel price is less than the sum of the parts so if you're capable of trueing etc.
		But their wheel price is less than the sum of the parts so if you're capable of trueing
	www.cyclingforums.com /t23715.html (1687 words)

	chattr +a -V: Problems on Hayabusa asteroid probe: another reaction wheel fails (Site not responding. Last check: 2007-10-09)
		The probe has three reaction wheels, which function like gyroscopes, that is, maintaining a particular orientation toward the asteroid Itokawa and the Sun.
		Two of the three reaction wheels have failed, one on July 31, the other on October 3.
		Without the reaction wheels, that orientation must be maintained by expending fuel, and of course, there's a finite amount of that on board.
	devmike.com /blog/archives/2005-10-07T15_10_32.html (184 words)

	Reaction wheel desaturation apparatus
		The development рrоvides an attitude manage actuation apparatus and approach to do reaction wheel desaturation.
		Two оr extra reaction wheeIs аre used for every of the three axis.
		The twо reaction wheeIs аre used to do a straightforward соst effectual electric powered desaturation оr slowing of the reaction wheeIs by exchanging momentum with every supplementary.
	www.patentalert.com /docs/000/z00061838.shtml (63 words)

	Integrated Reaction Wheel Assembly for Spacecraft Attitude Control from Goddard Space Flight Center
		Integrated Reaction Wheel Assembly for Spacecraft Attitude Control
		The National Aeronautics and Space Administration (NASA) seeks to transfer the Integrated Reaction Wheel Assembly (IRWA) technology to private industry.
		Developed by Goddard Space Flight Center for science missions, the IRWA offers companies an opportunity to virtually eliminate the technical risk and minimize the financial investment required to introduce a new spacecraft component.
	tco.gsfc.nasa.gov /ft-tech-wheel-assembly.html (444 words)

Try your search on: Qwika (all wikis)