Hub-and-spoke conspiracy involving other actors who are cooperating with the hub in carrying out the scheme. It is controversial, particularly in the antitrust cases, how much knowledge spoke actors must have of the conduct of other spoke actors—which is to say how much of a "rim" must be put around the "wheel" of the hub-and-spoke conspiracy for it to be a single conspiracy rather than many separate "vertical" conspiracies. There is a controversy and some uncertainty over the legal status of the "rimless" conspiracy—one with very limited interaction among the spokes. The leading two Supreme Court cases were "Interstate Circuit" and "Kotteakos".
Reaction wheel temporary changes in its speed result in small changes in angle. The wheels therefore permit very precise changes in a spacecraft's attitude. For this reason, reaction wheels are often used to aim spacecraft carrying cameras or telescopes. Over time, reaction wheels may build up enough stored momentum to exceed the maximum speed of the wheel, called saturation, which will need to be cancelled. Designers therefore supplement reaction wheel systems with other attitude control mechanisms. In the presence of a magnetic field (as in low Earth orbit), a spacecraft can employ magnetorquers (better known as torque rods) to transfer angular momentum