The Planetary Sunshade Institute advances the world’s understanding of space based sunlight reflection by working to answer the question ‘how could the world build a planetary sunshade?’ To do this, we:
- Organize world experts, including aerospace engineers, climate scientists, and governance leaders.
- Participate in governance development by engaging with the forums developing climate and space policy.
- Develop research funding, working with donors to advance priority areas.
- Design a sunshade system, constantly improving our understanding of the likely technical pathway
The concept:
‘Planetary sunshade’ refers to space based sunlight reflection for the purpose of global climate stabilization. This is one of two known methods to reflect sunlight at a global scale, the other being stratospheric aerosls. A planetary sunshade is not a substitute for reducing greenhouse gas emissions and removing carbon from the atmosphere, but instead compliments those efforts by offering tools for medium-term climate stabilization.
Size and location:
A planetary sunshade would be located near the Sun-Earth Lagrange 1 point, about 2 million km from earth, or about 6 times further than the moon. At this location, reflecting 1% of sunlight would require a total area of roughly 3 million km2. This would be achieved with a constellation of thousands of spacecraft, built mostly from huge reflective sheets of aluminum, all together weighing between 50 and 100 million metric tons.
Operation:
These craft could maintain position using solar radiation pressure as thrust – essentially, using the momentum of photons from the sun to have the sheets act as maneuverable sails. The shading on earth would be evenly distributed, and the sunshade would be invisible from earth.
Construction:
While initial components would be launched from Earth, the scale required would strongly incentivize the development of lunar resources to provide the vast majority of simple materials, notably aluminim sails and silicon cables.
Governance:
A sunshade is only possible with legitimate governance. Only governments can authorize and fund geoengineering deployment.
Status & Funding:
The planetary sunshade is in the early research stages of development, with engineering studies and climate models being used to evaluate feasibility and benefits. The Planetary Sunshade Institute is funded by the UK’s Advanced Research and Invention Agency. All results from this work are published and open-source, for the global public’s benefit.
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