Canada's da Vinci Project has high hopes of flying its private rocket to suborbital altitude next year. To do so, the group had to fabricate what it tags as the world's largest reusable helium balloon.

Balloon details were released by The Golden Palace.com Space Program Powered by the da Vinci Project. Steven Davies, balloon production team leader, said in a press statement that following months of preparation, "we turned out the final flight balloon using production equipment built by the project."

To haul the project's Wild Fire MK VI piloted spacecraft to launch altitude of 70,000 feet (21,340 meters), a 4,014-pound balloon was made from 4.5 mil thick custom extruded polyethylene sheets, measures 152.7 feet in diameter and 200 feet in length fully inflated. The balloon volume is 3,698,167 cubic feet (104,615 cubic meters) with a near record gross lift capability of 15,270 lbs (6,922 kilograms).

According to project team leader, Brian Feeney -- and pilot of the future suborbital attempt -- the private group successfully built and flew to 40,000 feet a smaller balloon scaled to simulate all the flight stresses in the summer. Sections of the final balloon were stress tested in a laboratory to 1,200 pounds per square inch, twice the expected maximum stress loads.

Feeney said in a press statement that the group also constructed a second 100,000 cubic foot test balloon. "This enabled us to perfect the manufacturing process as well as provide an additional large balloon for field launch testing. We even micrometer-tested the thickness of every 400 foot gore, every 12 inches, to be sure the material was within specification," Feeney added.

Several additional elements are engineered into the balloon design and recovery system to achieve the full reusability needed for multiple flights to space.

-- Leonard David