Here’s Why Starlink Lost 40 Satellites

Here’s Why Starlink Lost 40 Satellites

Better space weather forecast could have saved SpaceX Starlink satellites from solar storm.


In February, SpaceX lost 40 brand-new satellites after they were launched into a "mild" geomagnetic storm, demonstrating that even small solar outbursts can have massive consequences. An international team of researchers has outlined how to fix space weather forecasts in the future so that companies will not have to send their craft into such "treacherous waters."

An eruption of hot magnetised plasma erupted from the sun in late January of this year, causing space weather forecasters at the US National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center (SWPC) to warn of a mild geomagnetic storm.


SpaceX engineers were preparing 50 Starlink satellites to be launched on the company's Falcon 9 rocket at the same time. A model of Earth's upper atmosphere, into which their spacecraft was going to be placed, was used to run the data through the space weather alert. In spite of the analysis suggesting the environment was safe, all hell broke loose when the rocket discharged the payload at an altitude of 350 kilometres. It took the ground controllers longer than expected for 38 new satellites to reach their operational orbit of 550 km above the Earth because thin air around the spacecraft behaved differently than expected.


Starlink Satellites Become Victim Of Sun Particles Traveling At 662 Km/s


An investigation by SpaceX and NOAA experts has revealed that SpaceX might have changed its mind about that fateful launch had it followed NOAA's additional resources. 

NOAA launched its Whole Atmosphere Model (WAM) last year, which models processes in Earth's atmosphere up to 600 kilometres above the troposphere where terrestrial weather occurs. The model includes the thermosphere, the second-highest layer of Earth's atmosphere, where thin, diffuse gases cause drag that slows satellites down. 

There is a temporary increase in the density of thin air in the thermosphere when space weather occurs. At altitudes between 200 and 400 km, the density of the air increased by 50% to 125% during that geomagnetic storm. Such an increase in density would be like suddenly running against a very strong wind for satellites orbiting Earth at nearly 28,000 kph. 


Since the mishap, SpaceX has been working with NOAA to help improve space weather forecasts for satellite operators, Tzu-Wei Fang, a space scientist at the SPWC and lead author of the new study.

Currently, NOAA struggles with a lack of measurements from the critical region, which is why the company has started sharing data from its low-Earth orbiting satellites with them.

"This study demonstrates the benefits that can come from collaborative work between government and industry," Fang said in a statement. "The free exchange of model and satellite data and close interaction between SWPC and the Starlink team have enabled us to identify the quantitative impact of space weather events on these satellites, which help us to quickly prioritize our tasks to improve our space weather models and design the operational products that will better meet the needs of modern space commerce."


It is uncertain at this stage if Musk will confront the sun on twitter.


The space weather has caused problems for more than just SpaceX. Swarm satellites, which monitor Earth's magnetic field, have been sinking 10 times faster since December 2021 than in other years since their 2013 launch, the European Space Agency reported earlier this year. Due to the sun's current solar cycle, the 11-year cycle of ebbs and flows in the generation of sunspots and eruptions, there is an increase in solar activity. Furthermore, the current solar cycle has been much more active than space weather forecasters expected, and it follows a long period of quiet. 

A lot more small satellites are being launched into low Earth orbit during this period of disturbed space weather than during previous solar cycle peaks, experts warn. In many cases, these new satellites are simple CubeSats without onboard propulsion. Consequently, spacecraft may be unable to stay in orbit as long as they would like due to increased atmospheric drag caused by space weather.

The study concluded that it is "crucial for SWPC to establish suitable alerts and warnings based on [air] density predictions to provide users guidance for preventing satellite losses due to drag and to aid in collision avoidance calculations."


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