An unknown mechanism in plants may use titanium to stimulate the production of carbohydrates and encourage growth.

This technology, using titanium as the encasing metal, became the standard by the mid-1970s.

"We're not using titanium or magnesium, the kind of materials that are in the real Hubble," he said.

All new metalwork uses titanium, a strong, light, and corrosion resistant material.

"I don't think we'll ever use titanium," he said in a telephone interview from his Los Angeles office.

"I don't think we'll have the money to use titanium, so don't worry about it."

Using titanium rather than steel would have been ideal, but it was expensive and difficult to work.

We were using titanium quite a lot on the DN3, which was quite a new material then.

Other damping materials include products that use wood, titanium or synthetics.

The device uses textured titanium, which becomes coated with blood cells and forms a natural surface, he said.