There’s actually several small to medium effects on any spacecraft in orbit around earth. There will be tiny perturbations from the interaction of earths electr

There’s actually several small to medium effects on any spacecraft in orbit around earth. There will be tiny perturbations from the interaction of earths electromagnetic field as it moves through it slowly, there’s atmospheric drag on solar panels and the spacecraft body that can create “aerodynamic” torques related to what the normal orientation is relative to the earth. There’s even smaller perturbation from the solar wind… some spacecraft have a thing (or can fudge one using some part of the electrical subsystems) called a “magneto-torquer” which is basically a solenoid/electromagnet designed to tug on the earth’s magnetic field so they can trade electrical power for physical force. It’s a pretty cool thing that seems to be happening more and more frequently with spacecraft flight dynamics teams developing such a detailed model of all these forces that they can invent new “stable modes” like the one they used in this article, or the Kepler missions K2 mode where they found another useful mode instead of just ending the mission. It’s not as dramatic as something like a solar sailing mission, but I think it’s a pretty awesome technical achievement, like watching a trained stuntman drive a car on two wheels through a slalom course, like a form of highly skilled, kinetic, robot based gymnastics.