60 mph (since the forces applied during in developing the force-deflection curve were not taken to the point of failure, the wind capability of the prototype is likely to be in excess of this)
While the above gives a very rough estimate of the prototypes wind survival speed, the plan is to test performance in higher winds as soon as Mother Nature provides the winds.
It should also be noted that large inflated structures (e.g. tennis court enclosures) routinely withstand high winds with no damage.
In summary, the heliostat has demonstrated good, stable behavior in winds up to 30 mph. Further testing in higher winds is planned, but a rough analysis indicates that the performance in higher winds will be acceptable. Testing to date has demonstrated that the spherical shape is a good one for stable performance in high winds.
Figure 9d – Force/Deflection Curve for Prototype Heliostat
November 24, 2002