Is it possible to place a satellite in geostationary orbit over the north pole?
No, a geostationary orbit must be in the plane of the Earth's equator. That way, by matching its orbital speed with the speed of a point on the equator, the moving satellite appears to be stationary over that point. Any other orbit would have the satellite appear to drift above and below the equator during the course of a day.
A geosynchronous orbit matches the Earth's rotational speed, but only allows a satellite to appear over the same spot once per day. Depending on your stretch of that definition, a satellite in a perfect polar orbit would pass over each pole once per day and might be called 'geosynchronous', but like the time of day at the poles the terminology becomes ambiguous.
Paul Walorski, B.A., Part-time Physics/Astronomy Instructor
'The strength and weakness of physicists is that we believe in what we can measure. And if we can't measure it, then we say it probably doesn't exist. And that closes us off to an enormous amount of phenomena that we may not be able to measure because they only happened once. For example, the Big Bang. ... That's one reason why they scoffed at higher dimensions for so many years. Now we realize that there's no alternative... '