We saw it over SA on the early morning of the 19th May 2016. It's a NASA high altitude balloon at 100,000ft. It appears that the balloon is currently in the South Pacific, however, on the morning we tracked it over South Australia Airspace.
This is the link for the tracker...
http://l.facebook.com/l.php?u=http%3...NT&h=xAQFxgciG