Hello rc -
When the calibrate function is either not correcting a problem with spinning or drifting or is correcting it only briefly, there is another step you can try.
As a slight variation on the calibration process, you can intentionally mis-calibrate by holding the device cap away from center for several seconds and pressing the Calibrate button while the cap is off-center. Then, let the cap return to its center position and press Calibrate again while not touching the cap. By causing the distance away from center to become larger before re-zeroing, it can sometimes be more easily corrected.
If this does not correct the problem you should contact Technical Support
. If your Space Navigator is still under warranty they would be able to arrange for replacement.