[ExI] Obayashi Space Elevator

[Stuart LaForge]

The Obayashi Corporation, one of largest publicly-traded Japanese 
construction companies, has plans to complete a space elevator by the 
year 2050.

https://www.obayashi.co.jp/en/thinking/detail/space_elevator.html

"The space elevator is planned to be built by the year 2050 with a 
capacity to carry 100-ton climbers. It is composed of a 96,000-km carbon 
nanotube cable, a 400-m diameter floating Earth Port and a 12,500-ton 
counter-weight. Other facilities include Martian/Lunar Gravity Centers, 
an Low Earth Orbit Gate, a Geostationary Earth Orbit Station, a Mars 
Gate and a Solar System Exploration Gate.

The construction process consists of deploying the cable and 
constructing the facilities. It is necessary to analyze the cable 
dynamics in order to estimate the characteristics of the cable, 
counter-weight, facilities and climbers, and in order to determine the 
construction procedures. Parameters for the cable dynamics include 
tension, displacement and elongation of the cable due to ascending 
climbers, masses of counter-weight and cable, wind, and fixed loads of 
facilities. With the help of a computer simulation of the equations of 
motion, we designed the system and determined the construction process.

Based on the results, we conclude the following: construction will be 
technically feasible with an assumed cable tensile strength of 150 GPa, 
it will take roughly 20 years to construct the cable, the impacts of 
wind or Coriolis force on cable displacement are small, and it is 
essential to fix one end of the cable to the earth's surface, always 
applying pre-tension at the ground end. According to the plan, a 20-ton 
cable is deployed initially, and is reinforced 510 times by climbers up 
to 7,000 tons, ascending in succession over roughly 18 years. The 
facilities are then transported and constructed within one year."

By my estimation, this is so far the largest, most serious attempt at 
building such a structure. Keith, it looks like the years of advocacy by 
you and the others might be paying off.

Stuart LaForge