Satellites already use Earth's magnetic field for stabilization and manoeuvring, but we do it using devices which are orders of magnitude simpler and cheaper th

Satellites already use Earth's magnetic field for stabilization and manoeuvring, but we do it using devices which are orders of magnitude simpler and cheaper than the "EMDrive". They also generate more thrust. On the other hand, because they work by the known and proven laws of physics, rather than hand-waving, we already know that they'll only work in orbit of a planet with a magnetic field, and not deep space (or if you prefer, we can calculate just how useless they'll be in deep space, because there is an ambient magnetic field out there, even if it is tiny).