The tether would be made of existing commercially available materials : mostly Spectra 2000 ( a kind of ultra-high-molecular-weight polyethylene ), except for the outer 20 km which would be made of heat-resistant Zylon PBO . With a nominal payload mass of 14 tonnes, the Spectra / Zylon tether would weigh 1300 tonnes, or 90 times the mass of the payload.
32.
The only feasible way I see to get a good estimate is to take your cannon and carefully experiment with different payload masses and different powder quantities and try to work out a reasonable estimator . ( Also, your type of gunpowder might be different from the gunpowder mentioned in the documentary . ) Eric . talk ) 21 : 36, 22 May 2009 ( UTC)
