Even small solar outbursts can have massive consequences for the environment around Earth, space weather experts learned after SpaceX lost 40 brand-new satellites in February after launching them into a “mild” geomagnetic storm. In a new study, a team of researchers explain how to correct space weather forecasts in the future, in order to prevent companies from sending their craft into such “dangerous waters”.
At the end of January this year, an eruption of hot magnetized plasma erupted from the Sun towards Earthprompting space weather forecasters at the U.S. National Oceanic and Atmospheric Administration’s (NOAA) Space Weather Prediction Center (SWPC) to issue a mild geomagnetic storm warning.
At a time, SpaceX engineers were preparing a batch of 50 Stellar Link Internet satellites to be launched on the Falcon 9 rocket. They saw the space weather alert and ran the data through a model of Earth’s upper atmosphere, where they were about to place their spacecraft. Analysis suggested the environment was safe, but when the rocket discharged the payload at an altitude of 217 miles (350 kilometers), all hell broke loose. The thin air around the spacecraft behaved differently than ground controllers expected, and 38 of the new satellites quickly returned to Earth instead of climbing into their operational 340-mile (550 km) orbit. above the planet.
Related: NASA’s Planned ‘Ignorosphere’ Mission Could Improve Space Weather Predictions
The geomagnetic storm was quickly identified as the culprit behind the crash, and a new study by SpaceX and NOAA experts has now found that if SpaceX had tracked additional NOAA resources, the company might have changed his mind about that fateful launch.
Last year, NOAA released what it calls the Whole Atmosphere Model (WAM), which models processes in earth’s atmosphere up to the altitude of 370 miles (600 km), well above the troposphere where Earth weather occurs. The model includes the thermosphere, the second-highest layer of Earth’s atmosphere, where fine, diffuse gases cause drag that slows satellites.
When space weather hits, the thermosphere swells, the density of its thin air temporarily increasing. The study showed that during this geomagnetic storm, air density at altitudes between 125 and 250 miles (200 and 400 km) increased by 50% to 125%. For satellites orbiting the Earth at speeds of nearly 20,000 mph (28,000 km/h), such an increase in density would feel like suddenly racing against a very strong wind.
Since the accident, SpaceX has been working with NOAA to help improve space weather forecasting for satellite operators, Tzu-Wei Fang, space scientist at SPWC and lead author of the new study, told Space.com in a previous interview.
The company has even started providing data from its low Earth orbit satellites to the agency to improve the model, as NOAA is currently struggling with a lack of measurements of the critical region, according to Fang.
“This study demonstrates the benefits that can come from working collaboratively between government and industry,” Fang said in a statement. statement (opens in a new tab). “The free exchange of model and satellite data and the close interaction between SWPC and the Starlink team has allowed us to identify the quantitative impact of space weather events on these satellites, which helps us quickly prioritize our tasks. to improve our space weather models and design operational products that will better meet the needs of modern space commerce.”
SpaceX is not the only satellite operator to have encountered problems due to space weather. Earlier this year, the European Space Agency said its Swarm satellites, which monitor the Earth’s magnetic field, had been sinks 10 times faster since December 2021 than other years since their launch in 2013. The reason for this is the increase in solar activity as the sun moves towards the peak of its current solar cyclethe 11-year cycle of ebb and flow in the generation of sunspots and eruptions. Moreover, the current solar cycle turns out to be much more active than space weather forecasters had predictedand it comes after a prolonged quiet period.
Experts warn that the current period of disrupted space weather comes at a time when many more small satellites are being launched into low Earth orbit than during previous peaks in the solar cycle. Many of these new satellites are simple cubesats without onboard propulsion. The increase in atmospheric drag due to space weather can therefore significantly reduce the time the spacecraft can remain in orbit to carry out its missions.
The study concluded that it is “crucial for SWPC to establish appropriate alerts and warnings based on [air] density predictions to provide users with guidance to prevent satellite losses due to drag and to aid in collision avoidance calculations.
Other teams have warned that in the event of very severe solar storms, the changes in drag could be so large that the speeds and altitudes of orbiting satellites would change so much that computer algorithms that generate warnings when two objects, satellites or space debris, get too close to each other would become completely inaccurate.
It would take several weeks to trace all garbage and cubesats and synchronize the catalog with reality. During this time, operators would not receive accurate collision avoidance advisories and the chances of devastating collisions in orbit would increase dramatically.
Severe solar storms can also wreak havoc on Earth, causing power outages and disrupting GPS and radio signals. Although such powerful solar storms are not common, they can sometimes appear without warning.
The study (opens in a new tab)published in the AGU’s Space Weather journal, was published on November 2.
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