I did a thought experiment and I can't figure out what the mistake is.
There is a system of 2 electric motors weighing 1 kg each with batteries in the Earth's orbit.
The motors are rigidly connected by a 1-meter-long bar.
If one motor starts rotating in one direction on a signal, the entire system should start rotating in the opposite direction around(???) the motor's rotation axis.
After a while, we start rotating the motor in the opposite direction to stop the system from rotating.
As a result, we have a system in the same state but shifted 1 meter to the side.
Repeat the same with the second motor.
If this works, then you can make the motors' rotation axes perpendicular and move in any direction without exchanging masses.
There is a system of 2 electric motors weighing 1 kg each with batteries in the Earth's orbit.
The motors are rigidly connected by a 1-meter-long bar.
If one motor starts rotating in one direction on a signal, the entire system should start rotating in the opposite direction around(???) the motor's rotation axis.
After a while, we start rotating the motor in the opposite direction to stop the system from rotating.
As a result, we have a system in the same state but shifted 1 meter to the side.
Repeat the same with the second motor.
If this works, then you can make the motors' rotation axes perpendicular and move in any direction without exchanging masses.