 Alright, you guys asked for it, so today on Fidget Space, we are looking at gyroscopes. First off, gyroscopes should not be confused with reaction wheels, which I talked about in an earlier video, this one right here. Gyroscopes are different. They don't control spacecraft's orientation the way reaction wheels do. Instead, they give the spacecraft an inertial reference point in space, one that the guidance computer can use to activate reaction controls to change the spacecraft's orientation. If you've ever played with a gyroscope, you know that once you get a gyroscope spinning, you can do all kinds of weird things without it tipping over. You can balance it on the end of your finger and it won't wobble. That's because gyroscopes resist motion around their spin axis, but if they are forced to tip, they will tip 90 degrees from the direction from which they were pushed. In a spacecraft, the spinning gyroscope keeps the spacecraft stable. A spinning gyroscope keeps the spacecraft stable. Thrust rockets on the spacecraft fire occasionally to change the gyros' spin rate or rate of the spin-stabilized attitude. So stabilization in a spacecraft comes from getting the gyroscope spinning, and that can be as simple as getting the spacecraft itself spinning. Pioneers 10 and 11 had gyroscopes that spun because the spacecraft spun. But the Jupiter probe from the Galileo mission and the Huygens lander from the Cassini mission had gyroscopes that got their motion from the mothership before they were launched. But it doesn't matter. Once the gyroscope is spinning, it keeps the spacecraft stable. Then, thrust rockets can fire occasionally to change the gyroscope's spin rate or change the spin-stabilized attitude of the spacecraft. But gyroscopes aren't perfect. Mechanical gyroscopes can drift due to inertial friction. To compensate, drift rates are calibrated and work into the attitude control system so that the drift motion doesn't affect the spacecraft's overall mission. In aviation, a gyroscope does essentially the same thing. The X-15, for example, used a gyroscope. The gyroscope in an airplane will give the computer an inertial reference point. All the motion around the aircraft's axes of pitch, yaw, and roll are then calculated and displayed to the pilot in reference to that inertial reference point thanks to the gyroscope. So does that clear gyroscopes up for you guys a little bit? If not, leave your questions below and I will try to answer them as best I can. And if you have other questions or other topics you would like to see covered, leave those in the comments as well. If you want some old-timey space content every single day of the week, including lots of weird pictures dug out of online archives, be sure to follow me on Twitter as AST Vintage Space. And with new episodes going up every single Tuesday and Friday, be sure to subscribe right here so you never miss an episode.