Sun Umbrella Tied to an Asteroid Could Help Fight Climate Change, Study Reveals

Our planet is rapidly warming, and we are already experiencing the harmful effects of climate change. Scientists try to develop various approaches focusing on human activities that contribute to carbon emissions. An astronomer proposed a different method where the amount of sunlight that hits the Earth will be reduced.

Tethering a Huge Space Shield

Astronomer István Szapudi proposed the novel approach from the University of Hawai'i Institute for Astronomy. It involves using a solar shield and a captured asteroid to serve as a counterweight. The researcher hopes it can help create a workable design for mitigating climate change within decades.

One of the most straightforward solutions to reduce the global temperature is to protect the Earth from a fraction of the Sun's rays. This idea, known as a solar shield, has been proposed before. Still, the vast amount of weight required to make a guard massive enough to balance gravitational forces and avoid being blown away by solar radiation pressure has been a major concern.

The solution proposed by Szapudi involves two innovations. First, a tethered counterweight will be used instead of a massive shield, making the total mass over 100 times less. Second, a captured asteroid will be used as the counterweight, so most of the mass will not be obtained from Earth.

Szapudi aims to reduce solar radiation by 1.7%, as this is the estimated amount required to prevent the rise in global temperatures. He discovered that placing a tethered counterbalance toward the Sun can lessen the shield's weight and counterweight to an estimated 3.5 million tons, almost a hundred times lighter than previous approximations for an untethered guard.

This number is still far from current launch capabilities since only 1% of the weight would be the shield itself and the only part launched from the Earth. However, new and lighter materials can be used to reduce the shield's mass further. The other 99% of the total mass would come from the asteroids or lunar dust to be used as a counterweight. This tethered structure is a faster and cheaper approach to building and deploying other shield designs.

Our current technology only allows the enormous rockets to lift only 50 tons of objects to low Earth orbit, making this approach in solar radiation management challenging. Szapudi's proposal makes this idea possible even in the current technology, where previous concepts used to be unachievable. Developing a lightweight but strong graphene rope that connects the shield with the counterweight is also crucial.

Technology for Asteroid Capture

Astronomers can have different reasons for capturing and placing an asteroid into Earth's orbit. First, asteroid capture allows scientists to gain access to its resources. Second, doing so enables the experts to explore potential space habitats that can provide water, food, oxygen, and fuel. Lastly, placing an asteroid into Earth's orbit eliminates the possible collision threat.

Even a tiny asteroid weighs millions of tons, and we currently do not have available technologies to handle these chunks of rocks and place them wherever we want. Fortunately, we do not have to do it independently since it can be done using gravitational slingshots.

In this technology, one or more significant slingshots are used to adjust the asteroid's orbit to match Earth's. This can be done using the gravity of Earth, Moon, Mars, or Venus. The last step involves a final slingshot where the Moon is used to position the asteroid into a stable, highly eccentric Earth orbit (HEEO).