Most of the materials and equipment used in the construction of a virtual beanstalk are commonly commercially available and all are relatively well tested under the required operating conditions. There are as few exotic components as possible. However, the virtual beanstalk’s systems will be assembled in untried configurations. Safety requires that they be tested before final deployment. Since only a minimum of materials testing is necessary, the quickest way to perform a testing regimen is to assembly entire working systems for testing rather than proceeding one part at a time.

For example, the elevator can be fully assembled and tested using a kite blimp deployed to two kilometers high. Three kilometers high is the highest safe altitude for a typical tethered aerostat that does not itself employ some of our new techniques. However, aerostats capable of deploying to an altitude of more than one kilometer are commercially available, complete with all necessary support equipment.

Testing of the lift cells and rigging – particularly the proposed inflation schemes – can be conducted adequately using scale models for both the elevator and the platform. Testing of other systems, such as the crew cabins for the elevator and platform, will require the real thing. The platform to be used can also be deployed first as a free balloon for system testing without severe wind stresses.

All pressure tests can be performed adequately on the ground. The crew cabins are small enough to be tested in water pools before final assembly, using the typical water pressure tests used on any other type of tank. The balloon lift cells will be more problematic both to test and to quantify (their maximum pressure limits being about one thousandth that of the crew cabins), requiring testing to proceed for much longer periods.

I suggest we use two full scale platforms during the course of developing a virtual beanstalk. One will be the platform actually deployed to its full altitude. The other, built first, will be used for endurance testing and training. It would likely never exceed five kilometers high, but would be an invaluable test bed for working out kinks in the design. It’s important to note that the majority of the structural support provided to the platform will come from cable and rope rather than fixed struts. This could allow a great deal of flexibility in making adjustments to the final design plan. The entire platform performance can be adjusted with a hitch or a splice, and having a full scale platform to practice on would be invaluable.