Masterson, Development and validation of empirical and analytical
reaction wheel disturbance models, [M.S.
In the second three orbits, three magnetorquers and one
reaction wheel are used for the stable mode.
In low-altitude mapping orbit, Dawn will prolong its hydrazine supply by switching to a "hybrid mode" of pointing, where it will use its two remaining functional
reaction wheels in combination with hydrazine thrusters to point itself.
The redesigned
reaction wheels were successfully launched last year on the Transition Region and Coronal Explorer, a satellite mission that is studying the sun's coronal region with the TRACE satellite in April 1998.
Zhou, "A novel vibration isolation system for
reaction wheel on space telescopes," Acta Astronautica, vol.
Caption: Steadied by Sunlight: Kepler's new mission, K2, uses sunlight to make up for a lost
reaction wheel and keep the telescope balanced.
Yang, "Spacecraft attitude and
reaction wheel desaturation control," IEEE Transactions on Aerospace and Electronic Systems, vol.
Speaking on the debacle Charles Sobeck, deputy project manager at Ames Research Center, told Discovery News, "People are definitely saddened by the loss of another
reaction wheel. It certainly is not good news for the mission, which has been performing so well and had so much promise for doing even better."
After losing an attitude-controlling
reaction wheel in October, HALCA resumed observations in December but lost control of its orientation a second time later that month because of a commanding error.