Weathering the Solar Storms

West Virginia University engineer Piyush Mehta is currently engaging in several projects confronting space weather, which deals with the conditions within the Earth’s magnetosphere, ionosphere and thermosphere. Driven by the sun and solar wind, the impacts of space weather can influence technological systems in space and on ground and endanger human life and health, affecting power delivery, grid security, communications, satellite operations, collision avoidance and even radiation exposure for astronauts and commercial airlines passengers and crews.

In addition to the influx of satellites, millions of pieces of debris in orbit can threaten the Earth. Mehta explained that a debris particle the size of a paint flake can travel with enough speed and energy to cause critical, mission- ending damage to a functional satellite. Populating this region of space to a point of no return will result in a self-propagating chain of collisions, further endangering systems in orbit that control essential aspects of our daily lives — GPS, communication and internet connectivity.

A Storm Brewing

The danger of space weather is significantly amplified during solar and geomagnetic storms. According to Mehta, tackling space weather starts with better understanding the sun. It goes like this — at any given time, the sun releases a steady amount of charged particles into space. This is called solar wind. On occasion, these bursts of particles can be unusually strong and can create a geomagnetic storm.

“When space weather reaches Earth, it triggers many complicated processes that can cause a lot of trouble for anything that’s in orbit and in some cases on ground,” Mehta said.

As our dependency on technology increases, so does our vulnerability to space weather. Examples of major space weather events include the 1989 power blackout in Canada. The storm resulted in the North American Aerospace Defense Command losing track of hundreds of satellites and having to re-identify new orbits.

“In some instances, space weather can be strong enough that it can impact our power lines,” Mehta said. “Generally, our infrastructure can be fixed in a few hours or a day or two, but in the case of a Canadian winter, that can be very significant and dangerous and lead to casualties.”

The importance of more extensive space weather research was brought back into focus when a geomagnetic storm caused Elon Musk’s launch of 49 satellites slated to join SpaceX’s Starlink internet project to fail in February 2022. Each satellite burned up in the atmosphere, resulting in a $50 million loss.

What A Drag

The recent SpaceX loss has shown the challenge that we face with drag,” Mehta said. “We are trying to improve our models and our ability to forecast how a storm, even a small storm in this case of SpaceX, can change the state of the atmosphere and how it interacts with a satellite through drag, which can cause significant losses and direct damage.

“Higher density means more drag, which can be a problem for satellites. If you have ever put your hand out of a moving car window, you have experienced drag. The force of the wind pushing against your hand is similar to what a satellite endures while in orbit.”

Currently, there are about 2,000 active satellites in space. As more satellites are launched in the next 10 years, researchers will need to be able to predict drag more accurately to determine how much density, and subsequently, drag will change especially during active space weather conditions.

At this point, it’s impossible to accurately predict where a satellite is in space under changing weather conditions.

“Why that becomes important is that we need to be able to model the drag force well so that we can predict where the satellite is,” Mehta said. “As thousands of satellites are launched, space becomes crowded, and we have to think about how to keep these objects from colliding with each other.”

The Sunny Side

In a perfect world, satellite mega-constellations could hang out in low Earth orbit and let us enjoy the modern pleasures of the 21st century, like internet access in every remote corner of the Earth without interference. But the erratic and largely unpredictable nature of the sun, coupled with inadequate modeling and forecasting, spells disaster.

Mehta is optimistic, though, noting that Congress has recently passed a law that tasks federal agencies including NASA, the National Oceanic and Atmospheric Administration, National Science Foundation and Department of Defense, to address the threat of space weather.

Funded by NASA, NSF and the DoD, Mehta leads and is part of several space weather research projects including studies to achieve probabilistic modeling and forecasting of drag via AI and machine-learning.