The Scale of 1980’s SBSP Proposals
In 1980, NASA - National Aeronautics and Space Administration and U.S. Department of Energy (DOE) jointly proposed space based solar power (SBSP) as the next step for the space program. It would be a solution to the energy crisis that followed oil embargos [1] in the 1970's and could provide a perpetually source of energy going forward. Eventually, the proposal was shelved under the belief that coal and nuclear would be sufficient in coming decades. [2]
The proposed scale was huge. "The reference SPS, when completed at the end of a 30-year construction period, would produce 300 GW of electrical generating capacity." [3] That would be about 25% of the generation capacity in the US today. [4] The success of the Apollo program gave the team the confidence to propose this audacious upgrade to the US energy system.
The 300 GW was to come from 60 solar power satellites in geosynchronous orbit. Each satellite would consist of a solar array 5km by 10km with an antenna 1 km across to beam 5GW of clean, firm, renewable power to earth.
The scale of this endeavor is hard to visualize. The animation below shows the size of the satellite constellation compared to Manhattan and Long Island.
Even using 1970's technology, it would still have used less resources, minerals, and land than generating the same amount of energy with solar on the ground. This works because the sunlight in orbit is 5 to 50 times better than on the ground. Advances in electronics, materials, solar cells, and robotics mean that modern versions of space based solar power can be even smaller and more resource efficient.
References
[1] https://en.wikipedia.org/wiki/1970s_energy_crisis
[2] https://nss.org/wp-content/uploads/2017/07/1981-NRC-Electric-Power-From-Orbit-1-Report.pdf , pg 47
[3] https://www.eia.gov/energyexplained/electricity/electricity-in-the-us-generation-capacity-and-sales.php
More reading
· https://www.nrel.gov/docs/fy04osti/35097.pdf
