C H A P T E R
N ° 20
The May 2024 Space Weather Event
Solar physicists often refer to historical space weather events that have occurred decades ago. On SR Hoplon’s Blog we have introduced and discussed some of these to provide examples of why space weather awareness and the implementation of mitigation measures are important.
In today’s article, we will look closer at a historic space weather event that occurred not too long ago. We are going to take a short jump back in time to spring 2024 and explore the May space weather event. We will discuss the cause and impact of the event, and how this storm highlights some of the vulnerabilities within critical space and terrestrial (ground-based) infrastructures. Moreover, we will discuss why this event highlights the need for better space weather forecasting and warning capabilities, and the vulnerabilities within the modern-day agricultural sector.
Image Credit: NASA/SDO: NASA’s Solar Dynamics Observatory captured this image of a solar flare on 10 May 2024.
What happened?
On the 07’th of May 2024, a series of solar flares started to erupt from the Sun and continued until the 15’th of May. The responsible region on the Sun was AR3664, later renamed 3697. It started out with two strong Earth-directed solar flares on the 07’th of May. These were quickly followed by multiple strong solar flares and seven Coronal Mass Ejections (CMEs) that bursted out from the Sun towards the Earth between the 07’th and 11’th of May.
During this period, eight of the flares were within the highest category (X-class), with the strongest peaking at an intensity rating of X5.8. However, these events were later followed by many other larger flares, including an X8.7-class flare, which later revealed to be the most powerful flare of this current solar cycle (Solar Cycle 25).
The Coronal Mass Ejections (CMEs) were traveling at speeds of up to 3 million miles per hour (mph), and reached Earth more or less at the same time, starting on the 10’th of May. These created a long-lasting geomagnetic storm at an intensity level of G4 (i.e., severe) on the Geomagnetic Storm Scale published by the American meteorological governmental agency National Oceanic Atmospheric Administration (NOAA) Space Weather Prediction Center (the scales are currently under revision). On two occasions, the storm did, however, temporarily reach the conditions of a G5 (i.e., extreme), which is the highest level on the geomagnetic storm scale. A geomagnetic storm at these intensity levels (G4-G5) has not been seen since 2003.
* To learn more about solar flares and Coronal Mass Ejections (CMEs), please read: C H A P T E R N ° 1 Space Weather Basics. *
Image Credit: Behyar Bakhshandeh: Image showing sunspots 3664 (now 3697) and 3668, captured on 9 May 2024. The sunspots that caused the May 2024 space weather event.
The impact from the May 2024 space weather event
During the May 2024 geomagnetic storm, bright aurora was seen around the world, visible even at low altitudes such as the southern U.S. and northern India. The strongest and brightest auroras were seen at night on the 10’th of May and continued throughout the weekend. According to NASA, this event caused the most intense aurora seen for 500 years (i.e., half a millennium).
Image Credit: Christian Harris: Aurora looking west in Utica, OH the night of the 10’th.
In the days before the storm, the National Oceanic and Atmospheric Administration’s (NOAA) Space Weather Prediction Center, which is responsible for forecasts and warnings of space weather and impact, had sent out notifications to power grid and commercial satellite operators to help them prepare for potential effects caused by the space weather event. The American Space Weather Prediction Center even called in for a conference call with the North American power grid reliability coordinators to ensure that they were aware and prepared for what was potentially going to happen.
In the event, observers sent out warnings as soon as they detected the storms heading towards the planet. Events of this size generally take approximately three days to arrive. This provided satellite operators time to prepare a little in advance. However, although the warnings were made, it was not enough. Physicists have long known that space weather can disrupt circuits, interrupt communication, and change the trajectories of objects in Low Earth Orbit (LEO). This means, that although the warnings help operators to be aware and understand the potential experienced effects that can occur during the time of a space weather event, it does not eliminate the risk of disasters from occurring.
Furthermore, after the initial warning for the May event, the forecasts got poor. This was due to a significantly underprediction of the geomagnetic intensity leading up to the storm, and an overprediction in the days following afterwards, which highlighted the need for better capabilities within space weather forecasting and warning systems.
* To learn more about the different orbital classes, please read: C H A P T E R N ° 6 Space Weather and Low Earth Orbit (LEO); C H A P T E R N ° 7 Space Weather and Medium Earth Orbit (MEO); and C H A P T E R N ° 8 Space Weather and Geosynchronous Earth Orbit (GEO). *
Critical space infrastructure:
When solar physicists attempted to measure the changes in the Earth’s upper atmosphere caused by the geomagnetic storm at the time of the event occurring, they found that the density of the upper atmosphere at an altitude of 400 km (a part of Low Earth Orbit (LEO)) increased by a factor of 6, compared to 12 hours earlier.
The Earth’s atmospheric density decreases with increasing altitudes. The air, thus, gets thinner and provides less resistance the further up we get from the Earth’s mean surface level. When the atmosphere increases in density it slows down objects moving through it more, as these objects have to push aside more or ‘heavier’ molecules. The air resistance, thus, increases and causes what is called ‘atmospheric drag’. This significant change in the atmospheric density, therefore, caused an increase in the atmospheric drag on satellites at Low Earth Orbit (LEO). This was experienced by satellites like the Russian Kanopus-V3 Earth Observation (EO) satellite. Before the storm, the satellite had a decaying rate of 38 meters per day. However, during the storm it increased by a factor of four.
Furthermore, the geomagnetic storm, additionally, caused serious disruption to satellite operation capabilities for several days. This significantly increased the risk for all operating satellites located in Low Earth Orbit (LEO) to hazards such as atmospheric drag and, thus, re-entry of satellites, and satellites colliding with other satellites, space debris, or other objects in the near-Earth space environment.
Many modern satellites operate automatic station-keeping systems that maintain their orbit in real time. An example of this type of satellite is the Starlink satellites, which is an internet constellation with thousands of satellites. During the space weather event, this whole constellation had to perform maneuvers due to the increased atmospheric drag. However, the Starlink satellites are far from the only ones. The NASA ICESat-2 satellite that studies polar ice sheets automatically entered safe mode at the time of the event, most likely due to the increased drag caused by the solar storm, consequently making it highly difficult to operate.
* ‘Safe mode’ is an operating mode of a modern uncrewed spacecraft where all non-essential systems are shut down and only essential functions such as thermal management, radio reception, and attitude control are active. *
Besides the implementation of engineering shielding properties, it can be very difficult to protect satellites during space weather events. However, an example of a non-engineered based mitigation measure could be to deliberately shut down instruments aboard the satellites for a period of time. This means, that satellite operators would have to deliberately make their satellites go into safe mode. This was, for example, done by the American company Planet Labs during the May 2024 event. They paused imaging for their SkySat and SuperDove Earth Observation (EO) constellations for 24 hours from the 10-11’th of May to mitigate potential risks. Yet, as mentioned, this would increase the risk of re-entry and collisions, consequently making this a less ideal mitigation measure.
The energy sector:
Since the late 1970’s, research on the relation between space weather and the energy sector have shown that extreme space weather has the capability to disrupt normal power delivery. Many historical space weather events and the modelling of impact from severe and extreme events on the energy sector have proven that it is possible. During the May 2024 event this was again highlighted, as the American power transmission systems got significantly affected.
Although the power systems stayed intact and, thus, did not collapse, stresses were felt on the system. This caused the need of numerous grid operation procedures to be enforced. Without the understanding of space weather as a phenomenon, awareness through forecasts and alerts, and preparedness, the impact may have looked different.
The high stresses on the power grid system were due to incoming high Geomagnetically Induced Currents (GICs) that were starting to interact with the grid. As the Geomagnetically Induced Currents (GICs) infiltrated the system, transformer tripping reports started to come in, followed by a reduction of operations on the transformers. This was followed by several top oil temperature alarms going off, tripping of harmonic filters on a 345 kV transmission line, capacitor bank tripping, transmission line tripping, and High-Voltage Direct Current (HVDC) link Tripping. Additionally, solar inverters (photovoltaic (PV) inverter) started exhibiting unusual oscillations, and the voltage dropped noticeably during the peak of the space weather event.
* Solar inverter/photovoltaic (PV) inverter is a type of power inverter which converts the variable direct current (DC) output of a photovoltaic solar panel. *
* To learn more about the different orbital classes, please read: C H A P T E R N ° 14 Space Weather and The Energy Sector; C H A P T E R N ° 15 Space Weather and Power Grids; and C H A P T E R N ° 16 Space Weather, Power Grid Systems, and Mitigation Measures. *
The agricultural sector:
A sector that often gets neglected when discussing space weather impact is the agricultural sector. The May 2024 space weather event was, however, a testimony to the fact that not even this sector is immune to the effects of this natural hazard. The space weather event occurred at a time that is known to be the most crucial planting timeframe for American farmers. It was the time of year when planting and seeding was happening across the United States. The timing for the event is extremely important for farmers in order for their crops to be ready for later in the year. Thus, if the storm had happened in the beginning of the year, the American agricultural sector would not have experienced any significant issues.
During the 2024 event, the storm caused a Global Positioning System (GPS) outage that lasted a least four hours, and had lingering effects. Given that approximately 70% of the American farmers rely on the Global Positioning System (GPS) to guide them when planting and seeding, it was felt across the country and had significant effects.
With the use of tractors and the Global Positioning System (GPS) providing visual markers, a farmer can expect to overlap rows by approximately 10% with each pass. This means, that with a 40-foot cultivator that would give 36 feet of work. With certain types of positioning systems, such as Real Time Kinematic positioning (RTK) that helps correct common errors in the current systems within the Global Navigation Satellite System (GNSS), farmers can minimize the overlapping to approximately 1 cm. Using modern agricultural equipment, thus, dramatically reduces the overlap of seeds and helps farm a lot more acres in less amount of time.
Things that the space weather event, therefore, highlighted, were questions such as: ‘what would happen if the Global Positioning System (GPS) was taken away for half a day like what happened during the May 2024 space weather event, or more?’ and, ‘how much would the farmers schedule be pushed back, and what would the consequences be of such a disruption?’.
The May 2024 space weather event was followed by weeks of rain, which exacerbated its impact, as the American farmers were already running late due to the solar storm. When comparing the situation to May during the previous year, 2023, farmers had planted approximately 60% of corn crops around the 12’th of May. This number significantly decreased to approximately 49% in 2024 by that same date. Similarly, the planting of 45% of soybean crops were finished by May 12, 2023, whereas only 35% were planted the year of the space weather event.
According to Professor Emerson Dale Nafziger at University of Illinois Urbana-Champaign, corn planted in mid-April produces the maximum yield possible. The harvest of corn planted in mid-May is approximately 95%, whereas it decreases to 85% by June. The May 2024 space weather event pushed the planting timeline, consequently causing a marginal acre to be pushed back to the end of the season (i.e., the least ideal planting window). According to Professor Terry Griffin from Kansas State University, the yield penalty could be approximately 20-80% of maximum harvest. The May 2024 space weather event, thus, highlighted the significant yield penalties possible to face farmers due to the agricultural sector’ dependency on space infrastructure.
The financial loss for the agricultural sector does, however, depend on multiple factors, such as; 1) when farmers were able to resume planting; 2) the type of equipment used. For example, farmers using mechanical row markers showed to have experienced no affects by the space weather event; 3) how inefficient or imprecise their machines became if they chose to plant through the Global Positioning System (GPS) disruption; and 4) how well they were able to make up ground after the delay.
Professor Terry Griffin describes the financial loss from the 2024 event to be insignificant to some farmers when looking at it per acre as it would be a loss of approximately 1-2%. However, the yield penalties for farmers delayed more significantly is argued to be more severe and significant at a national level. Professor Terry Griffin estimated that affected farms would lose approximately 1 USD per acre, which nationally would equate to a lost earning potential of 500 million USD. This is without considering cascading and downstream effects.
The total effects of the May 2024 space weather event on the American agricultural sector could not be estimated with certainty in 2024. During the space weather event, the Global Positioning Systems (GPS) dependent machines used by farmers did not collect accurate data due to the outage. Additionally, guess rows were skewed, which could have had an effect on the efficiency and data-collection capabilities of machines during spraying and harvesting activities. Data could, thus, be missing.
Furthermore, the data collected through space infrastructure services is not only important to farmers. Seed representatives, retailers, and universities are, likewise, dependent on the field data to support their own programmes and businesses. Without knowing what actually went into the field, the on-farm experiments are inadequate, consequently affecting the farmer’s ability to compare hybrids and varieties. This would have a significant ripple effect after 2024, as agricultural studies rely on multiple years of research and investigations. The real impact from the May 2024 space weather event will, thus, potentially first be known in the upcoming years.
Image Credit: Tiffany Graham: A tractor on the O'Connor Family Farm in Blooming Prairie under the northern lights.
The May 2024 space weather event later got the name ‘Gannon Storm’ in memory of the space weather physicists Jennifer Gannon.
Source
ESA (2024): “The May 2024 solar storm: your questions answered”. https://www.esa.int/Space_Safety/Space_weather/The_May_2024_solar_storm_your_questions_answered.
NASA; Young, Lacey (2024): ”Continuing Strong Solar Flares: May 15-16, 2024”. https://svs.gsfc.nasa.gov/14593/.
NASA; Johnson-Groh, Mara (2024): ”How NASA Tracked in the Most Intense Solar Storm in Decades”. https://science.nasa.gov/science-research/heliophysics/how-nasa-tracked-the-most-intense-solar-storm-in-decades/.
Werner, Debra (2004): “What the biggest solar storm in decades revealed about space system resilience”. https://spacenews.com/what-the-biggest-solar-storm-in-decades-revealed-about-space-system-resilience/.
Tood, Iain (2024): “That sunspot that caused the 10 May aurora display? It’s back, firing off strong solar flares and is not alone”. https://www.skyatnightmagazine.com/news/solar-flare-ar-3697-geomagnetic-storm.
Science That Matters; The Physics arXib Blog (2024): “Satellite Collision Prediction Lost During Recent Solar Storm”.https://www.discovermagazine.com/technology/satellite-collision-prediction-lost-during-recent-solar-storm.
LiveScience; Baker, Harry (2024): “Recent auroras may have been the strongest in 500 years, NASA says”. https://www.livescience.com/space/the-sun/well-be-studying-this-event-for-years-recent-auroras-may-have-been-the-strongest-in-500-years-nasa-says.
