Thank you very much! It was, in fact, _not_ mounted to "/media/SPAACE".
It was mounted to "/media/SPAACE_". Notice the underscore at the end of the latter.
What was really weird is that Nautilus showed it's path to be "/media/SPAACE"
(there was a "media" button followed by a "SPAACE" buttion. No "SPAACE_" button).
And it showed up as the "SPAACE" drive in the left pane.
In Nautilus ran as root, however, the true colors showed. Root Nautilus showed it as
the "SPAACE_" drive in the left pane and the buttons on top showed "media" and
"SPAACE_".
The "mount" command in terminal was saying the right thing all along, but I just
didn't notice the underscore.
Jake