That's a loaded assumption. Orbiting the earth, external forces would still be acting upon the gyroscope. Earth's gravity (inversely proportional to distance but still significant to at least the moon and beyond), Jupiter's gravity, solar wind, solar particles, impact particles, van Allen belt magnetics, etc. Of course, the whole Milky Way galaxy is gravitationally wedded, as is the local galaxy cluster so I'm not sure how one would design an experiment "free from external forces".
You don't have to. That was just put in the article by way of explanation: even if there are no external forces, the axis will precess, because spacetime itself is twisting.
What you need in the real world is an experiment where all external forces have been accurately accounted for.