Steve is President and CEO of the Aerospace Corporation, a critical organization in the history of the space industry that sits at the intersection of public and private aerospace.
Was reading about the new Webb Telescope and was surprised to read about its reaction wheels. Whoa! So it can adjust its position using electrical energy by changing the spin of reaction wheels... Good ol Newton's third law comes in handy. Doesn't need to rely on conventional propellants/gas/etc? In an interview of its chief scientist, however, he said that they periodically need to "reset" the reaction wheels with the help of propellants. Is this something that is unique to a BIG project like the Webb, or do smaller satellites use this approach.
Also, per one of my personal areas of interest (Lagrange Points), I see that Webb will be orbiting L2 (I believe) so it can both be in the Earth's shadow and also in the sun's rays. So much to know.
Thank you for reading! Yes, reaction wheels are awesome tools that allow you to change the orientation of the spacecraft because when they spin, the angular momentum of the whole satellite must be conserved so the rest of the system must rotate to compensate. As you mentioned, if you want to be able to stop using the reaction wheels but maintain the satellites orientation, you have to eject something (in the form of the propellent) while spinning down the wheels. Thats true for any spacecraft!
Nice posting. Great interview.
Was reading about the new Webb Telescope and was surprised to read about its reaction wheels. Whoa! So it can adjust its position using electrical energy by changing the spin of reaction wheels... Good ol Newton's third law comes in handy. Doesn't need to rely on conventional propellants/gas/etc? In an interview of its chief scientist, however, he said that they periodically need to "reset" the reaction wheels with the help of propellants. Is this something that is unique to a BIG project like the Webb, or do smaller satellites use this approach.
Also, per one of my personal areas of interest (Lagrange Points), I see that Webb will be orbiting L2 (I believe) so it can both be in the Earth's shadow and also in the sun's rays. So much to know.
Thank you for reading! Yes, reaction wheels are awesome tools that allow you to change the orientation of the spacecraft because when they spin, the angular momentum of the whole satellite must be conserved so the rest of the system must rotate to compensate. As you mentioned, if you want to be able to stop using the reaction wheels but maintain the satellites orientation, you have to eject something (in the form of the propellent) while spinning down the wheels. Thats true for any spacecraft!