For now the concept exists only in engineering studies and climate models. According to the institute, only governments can authorize and fund a deployment.<\/p>\n\n\n\n
Blades 6 miles long<\/h2>\n\n\n\n
The institute’s favored design uses heliogyros, a type of solar sail with long, thin blades around a central hub. Its engineering page<\/a> lists each craft at 25 miles (40 kilometers) across and 13,000 metric tons. The aluminum blades and silicon cables each run about 6 miles (10 kilometers).<\/p>\n\n\n\n Under this plan, factories on Earth would make only the hubs. Those would hold the computer, batteries, sensors and motors.<\/p>\n\n\n\n The fleet would gather about 1.47 million miles (2.36 million kilometers) from Earth, near the Sun-Earth Lagrange 1 point. Objects in that region circle the sun in step with Earth, so they can shade it around the clock.<\/p>\n\n\n\n The spot is not perfectly stable, the institute’s climate science page<\/a> explains. Each craft would keep correcting its position by tilting its surfaces and using sunlight as thrust.<\/p>\n\n\n\n Together, the craft would provide about 1.16 million square miles (3 million square kilometers) of shade. The institute says the dimming would be even and invisible from the ground.<\/p>\n\n\n\n Multiplying 5,000 craft by 13,000 metric tons gives 65 million metric tons. The institute’s press page gives a range of 50 million to 100 million.<\/p>\n\n\n\n An earlier literature review by the institute put everything humanity had launched to orbit at 15,000 tons. By that older tally, the fleet would weigh more than 4,000 times as much.<\/p>\n\n\n\n Launching it all from the ground would carry a climate bill of its own, including greenhouse effects and ozone damage, the institute warns. Rockets also bring other risks, such as the falling debris that concerns airlines<\/a>.<\/p>\n\n\n\n An older benchmark aimed for more shade. A 2015 paper in PLOS ONE<\/a> noted that most scenarios target a 1.7 percent cut in sunlight, enough to offset doubled carbon dioxide. Its authors, Joan-Pau S\u00e1nchez and Colin McInnes, calculated a disk of about 2.5 million square miles (6.5 million square kilometers).<\/p>\n\n\n\n According to the survey, two factors will set the schedule. One is how often heavy-lift rockets can fly, and the other is how fast large-scale lunar mining develops.<\/p>\n\n\n\n Early demonstrations would almost certainly leave from Earth. Even so, the institute considers it very likely that the Moon would end up supplying the vast majority of the mass.<\/p>\n\n\n\n By the institute’s figures, lifting material from the lunar surface to the sunshade’s position takes about 1\/35th of the fuel needed from Earth. Space mining has its own rivals, and China has set long-range goals of its own<\/a>.<\/p>\n\n\n\n In 1989, James Early of Lawrence Livermore National Laboratory proposed “a thin glass shield built from lunar materials” near the first Lagrange point.<\/p>\n\n\n\n Earth orbit fares badly in a September report by the institute’s executive director, Morgan Goodwin. A cut of just 0.1 percent from there would take 464,000 craft. Each satellite in that shell would be struck three to four times a year.<\/p>\n\n\n\n Shading the planet would leave carbon dioxide in the air, and the institute says a sunshade cannot replace emissions cuts. Oceans absorb about 25 to 30 percent of human carbon dioxide emissions, so acidification would keep threatening corals.<\/p>\n\n\n\n Global precipitation would also fall if shade cooled the world while carbon dioxide stayed high, the climate page says. A uniform dimming would cool the tropics more than higher latitudes.<\/p>\n\n\n\n Similar worries surround solar geoengineering with sulfur balloons<\/a>, the other known global method. The survey says a sunshade could be adjusted within days. It adds that blocking only certain wavelengths might ease the rainfall problem, although that result is very preliminary.<\/p>\n\n\n\n Among the alternatives in the survey, a controlled cloud of dust offers a 600-fold mass advantage over sails. The institute cautions that work to verify control of such a cloud is at an early stage.<\/p>\n\n\n\n A roadmap for the sail-based route, by Catello Leonardo Matonti and nine co-authors in Advances in Space Research, targets initial operations by 2040 and full capability by 2080.<\/p>\n\n\n\n Chantal Cappelletti, one of those co-authors, works with the NottSpace team at the University of Nottingham. She helped organize a meeting of about 20 participants at the International Astronautical Congress in Antalya, T\u00fcrkiye.<\/p>\n\n\n\n Afterward she wrote that “many of the technological building blocks required for a Planetary Sunshade system are already under active development.”<\/p>\n\n\n\n Construction cost is the largest blank on the institute’s public pages, which give no price for the fleet. Several papers behind the survey are also still going through peer review.<\/p>\n\n\n\n No body currently exists to decide whether a sunshade gets built, the institute acknowledges. It also accepts that the project could tempt governments to ease off on decarbonization.<\/p>\n\n\n\n Its home page warns that “the capability to build a planetary sunshade is arriving faster than the governance to oversee it.” The governance page names SpaceX as the only private company for which such a project is conceivable.<\/p>\n\n\n\n The main source is the institute’s 2026 Space Reflector Baseline Survey summary<\/a>, together with its technical pages.<\/p>\n\n\n\n Image: Planetary Sunshade Institute<\/p>\n","protected":false},"excerpt":{"rendered":" A planetary sunshade made of about 5,000 spacecraft would block 1 percent of incoming sunlight and cool Earth by about … <\/p>\n![\"Diagram](\"https:\/\/www.ecoticias.com\/en\/wp-content\/uploads\/2026\/11\/sun-earth-lagrange-diagram.jpg\")
65 million metric tons of hardware<\/h2>\n\n\n\n
Aluminum and silicon from the Moon<\/h2>\n\n\n\n
Rain, oceans and uneven cooling<\/h2>\n\n\n\n
A dust cloud 600 times lighter<\/h2>\n\n\n\n
![\"Participants](\"https:\/\/www.ecoticias.com\/en\/wp-content\/uploads\/2026\/11\/iac-sunshade-study-group.jpg\")
Who pays and who decides<\/h2>\n\n\n\n