Expo '70's Mushballoons

I'm fascinated by these structures that were in Expo '70's amusement zone, Expoland. The park lived on for decades after 1970 and I'd love to find out whatever became of these structures... and how well they survived in the elements.



The text accompanying the photos says:

"This is called the Mushballoon because it is shaped like a mushroom. The Mushballoons are the centerpiece of the Space of Planets in Expoland. They are elegant and dynamic in appearance.

The huge cushion of air is suspended by 45 strands of wire. The wires are all brought together and connected through a tube to a winch in the basement. When the winch is wound, the mushroom collapses in 15 minutes. The Mushballoons rest at night and bloom again in the morning. The diameter of one Mushballoon is 30 meters, that of another 20 meters, and that of the three others 15 meters.

Architectural Design: Taneo Oki Architects
Structural Design: Shigeru Aoki Research Office"

I found more information (including some cool diagrams) at:
http://www.tensinet.com/database/viewProject/3839.html