Editing CubeSat (section)

===Attitude control===
[[File:Near Earth Asteroid Scout.jpg|thumb|[[Near-Earth Asteroid Scout]] concept: a controllable [[solar sail]] CubeSat]]
[[Spacecraft attitude control|Attitude control]] (orientation) for CubeSats relies on miniaturizing technology without significant performance degradation. Tumbling typically occurs as soon as a CubeSat is deployed, due to asymmetric deployment forces and bumping with other CubeSats. Some CubeSats operate normally while tumbling, but those that require pointing in a certain direction or cannot operate safely while spinning, must be detumbled. Systems that perform attitude determination and control include [[reaction wheel]]s, [[magnetorquer]]s, thrusters, [[star tracker]]s, [[Sun sensor]]s, Earth sensors, [[angular rate sensor]]s, and [[GPS navigation device|GPS receivers and antennas]]. Combinations of these systems are typically seen in order to take each method's advantages and mitigate their shortcomings. [[Reaction wheels]] are commonly utilized for their ability to impart relatively large [[Moment (physics)|moments]] for any given energy input, but reaction wheel's utility is limited due to saturation, the point at which a wheel cannot spin faster. Examples of CubeSat reaction wheels include the Maryland Aerospace MAI-101<ref>{{Cite web| url = http://maiaero.com/products/s/mai-101/| title = Maryland Aerospace Reaction Wheels| access-date = September 4, 2015| url-status = dead| archive-url = https://web.archive.org/web/20150716161428/http://maiaero.com/products/s/mai-101/| archive-date = July 16, 2015}}</ref> and the Sinclair Interplanetary RW-0.03-4.<ref>{{Cite web| url = http://www.sinclairinterplanetary.com/reactionwheels| title = Sinclair Interplanetary Reaction Wheels| access-date = September 4, 2015| archive-date = September 24, 2015| archive-url = https://web.archive.org/web/20150924101944/http://www.sinclairinterplanetary.com/reactionwheels| url-status = dead}}</ref> Reaction wheels can be desaturated with the use of thrusters or magnetorquers. Thrusters can provide large moments by imparting a [[Couple (mechanics)|couple]] on the spacecraft but inefficiencies in small propulsion systems cause thrusters to run out of fuel rapidly. Commonly found on nearly all CubeSats are magnetorquers which run electricity through a coil to take advantage of Earth's magnetic field to produce a [[Moment (physics)|turning moment]]. Attitude-control modules and solar panels typically feature built-in magnetorquers. For CubeSats that only need to detumble, no attitude determination method beyond an [[angular rate sensor]] or electronic [[gyroscope]] is necessary.

Pointing in a specific direction is necessary for Earth observation, orbital maneuvers, maximizing solar power, and some scientific instruments. Directional pointing accuracy can be achieved by sensing Earth and its horizon, the Sun, or specific stars. Sinclair Interplanetary's SS-411 Sun sensor<ref>{{Cite web| url = http://www.sinclairinterplanetary.com/digitalsunsensors| title = Sinclair Interplanetary Sun Sensors| access-date = September 4, 2015| archive-date = November 17, 2015| archive-url = https://web.archive.org/web/20151117032733/http://www.sinclairinterplanetary.com/digitalsunsensors| url-status = dead}}</ref> and ST-16 star tracker<ref>{{Cite web| url = http://www.sinclairinterplanetary.com/startrackers| title = Sinclair Interplanetary Star Trackers| access-date = September 4, 2015| archive-date = September 24, 2015| archive-url = https://web.archive.org/web/20150924101946/http://www.sinclairinterplanetary.com/startrackers| url-status = dead}}</ref> both have applications for CubeSats and have flight heritage. Pumpkin's Colony I Bus uses an aerodynamic wing for passive attitude stabilization.<ref>{{Cite web| url = http://www.cubesatkit.com/docs/press/Pumpkin_GAINSTAM_2009.pdf| title = Pumkin's Colony I CubeSat Bus| date = 4 Nov 2009| access-date = September 4, 2015| last = Kalman| first = Andrew}}</ref> Determination of a CubeSat's location can be done through the use of on-board GPS, which is relatively expensive for a CubeSat, or by relaying radar tracking data to the craft from Earth-based tracking systems.