Something hit me this morning when I was still in bed. On the last video the astronaut seems to not understand what happens when you add more that one gyroscope !
What is much more surprising is that nobody in NASA told him!
Perhaps he designed the demonstration without outside vetting and this was broadcasted live so now it lives in youtube and NASA cannot take it back
If you add two gyroscopes at 90 degrees to each other, it is equivalent to a single gyroscope aligned along the middle (bisector, if they are spinning in the "same" sense). The thing would still be able to rotate around this axis and the stabilization would be less than stacking the two CD players on top of each other. The reason is that along the perpendicular axis the rotation of the two CD players cancel each other (like two gyros spinning in opposite directions cancel each other).
When he added the 3 CDs at 90 degrees to each other he just got the equivalent to one aligned with the axis going through the center of the corner angle. But he would get just 1.7 times the angular moment of one CD instead of the 3 times if he had stacked them all together.
By the way, somewhere there must be video of the demonstrations Nasa did with tops and described in this book:
From the
Papyrus section: "Nasa´s Toys in Space program flew several tops in two Shuttle flights. The tops included a pump top, a tippy top, a rattleback, gravitrons and gyroscope. Other spinning toys included a yo-yo and a magnetic wheel. "
