Study warns extreme space weather may disrupt flights, expose passengers to radiation

Extreme space weather could soon become an operational problem for commercial aviation, forcing airlines to reroute aircraft, restrict polar services or even ground flights, according to research led by the University of Surrey. The study, published in the Journal of Space Weather and Space Climate, presents one of the most detailed assessments yet of how powerful solar storms can affect both human health and the electronic systems on which modern aircraft depend. Its authors argue that aviation has traditionally treated radiation as a background environmental hazard, but the most severe events can transform it into a rapidly escalating safety issue at cruising altitude.

Researchers at the Surrey Space Centre found that radiation exposure can rise sharply at the altitudes used by most commercial aircraft, typically between 8 and 14 kilometres above the ground. At these heights, the atmosphere is thinner and provides less shielding from energetic particles arriving from space. Under ordinary conditions, aircraft occupants already receive more radiation than people at ground level, because cosmic rays collide with atmospheric molecules and generate secondary particles, including neutrons, that can penetrate aircraft cabins. During an extreme solar particle event or geomagnetic storm, however, the radiation environment can change within minutes or hours.

The most immediate biological concern is increased exposure to ionising radiation, which has enough energy to remove electrons from atoms and damage living tissue. A single severe event would not necessarily produce an acute radiation sickness risk for passengers, but it could substantially increase the dose received by flight crews, frequent travellers and aircraft operating repeatedly through affected regions. Measurements associated with a major solar storm in November 2025 showed radiation levels at high altitude briefly approaching ten times normal flight conditions. The researchers also compared present-day aviation conditions with the historic solar storm of February 1956, the strongest event in the modern record, concluding that passengers exposed during such an episode could receive a dose comparable to a year of routine flight-related cosmic radiation in a single journey.

For airlines, the threat may be even more serious inside the aircraft’s computers than inside its cabin. High-energy particles can pass through semiconductor devices and deposit electrical charge in sensitive circuits. This can produce a phenomenon known as a Single Event Upset, or SEU, in which a stored bit changes from zero to one or from one to zero, potentially altering a calculation, a command or a piece of data. Many SEUs are corrected automatically through redundancy, error-detecting codes or system resets. Yet during an intense particle event, the number of errors can rise from a few per hour to thousands, increasing pilot workload and creating the possibility that several supposedly independent systems could experience faults at the same time.

The vulnerability is growing as aircraft become more dependent on digital flight controls, networked computers and lightweight electronic components. Modern avionics are designed to withstand routine radiation environments, but extreme space weather can push systems beyond the conditions used in conventional certification and reliability testing. The issue became especially visible after Airbus temporarily grounded about 6,000 A320 aircraft after identifying a vulnerability to intense solar radiation in a flight-control computer. The weakness came to light following an incident in October 2025, when a JetBlue flight travelling from Cancún to Newark made an emergency landing in Florida. Although individual events do not prove that a solar storm caused a particular aircraft malfunction, the episode highlighted how radiation-induced errors can move from an invisible space-weather process to an operational aviation emergency.

The highest routine exposure occurs on polar routes, including services linking London Heathrow with Vancouver International Airport. Earth’s magnetic field normally deflects many charged particles away from the atmosphere, but its protective effect is weaker near the poles. Solar particles can therefore penetrate more deeply over high-latitude flight paths, where aircraft may already be operating in an environment with elevated radiation and reduced options for diversion. Severe geomagnetic storms can expand the affected region towards lower latitudes, however, meaning that the risk is not confined to polar aviation. During sufficiently powerful events, routes over the United Kingdom and other mid-latitude regions could also experience significant increases in radiation and electronic upset rates.

The research identifies a weakness in current aviation safety frameworks: existing procedures generally address normal occupational exposure and some known solar-particle alerts, but do not provide a consistent system for judging the combined effects of radiation dose and avionics disruption during an extreme event. An alert based only on low-energy protons can produce many warnings without a meaningful increase in the radiation environment at flight level. Professor Clive Dyer, a co-author of the study, said that current alerts generate at least ten false alarms for every true alert because they do not adequately represent the high-energy particles most relevant to aviation.

To improve decision-making, the Surrey team has proposed a new atmospheric radiation scale designed specifically for aircraft operations. Rather than relying on a single measurement, the scale combines high-energy proton observations from space with data from ground-level neutron monitors, including instruments at Surrey, Lerwick and Camborne. It is intended to connect the physical conditions in space with practical aviation consequences, including estimated human dose and the likelihood of SEUs in flight electronics. The researchers say that a graded system could allow airlines and regulators to move proportionately from increased monitoring to changes in altitude, route alterations, flight restrictions or temporary grounding, instead of reacting either too late or unnecessarily to ambiguous warnings.

The proposed framework is also intended to work with existing modelling and monitoring technologies. The team points to MAIRE, a radiation modelling system used to estimate aviation exposure, and SAIRA, an aircraft-based monitoring capability designed to measure the radiation environment during flight. Together with real-time space-weather observations, these tools could help operators determine whether a storm is likely to affect a particular route, how long the disruption may last and whether avoiding the affected region would be safer and more economical than continuing normally. The researchers emphasise that this kind of information must be integrated into flight planning systems rather than delivered as a specialist warning that arrives after an aircraft has already departed.

Dr Fan Lei, lead author of the study and a senior research fellow at the Surrey Space Centre, said the recent A320 grounding demonstrated that space weather is no longer a theoretical risk for aviation. As aircraft systems become more sophisticated and increasingly reliant on electronics, he argued, understanding the interaction between energetic particles, flight computers and human exposure will be essential to maintaining safety. Professor Keith Ryden, who co-authored the study, said the new scale could give operators a clearer basis for rapid decisions during extreme events. The researchers now hope their approach will support common international guidance, allowing airlines, aircraft manufacturers and regulators to respond to the next major solar storm with a shared understanding of when a warning should become an operational action.

News Publication Date:
11 August 2026

Web References:
https://doi.org/10.1051/swsc/2026025

References:
Lei, F., Dyer, C., Ryden, K. et al., “Assessment of impacts to aviation radiation by extreme space weather events and new atmospheric radiation scales,” Journal of Space Weather and Space Climate, DOI: 10.1051/swsc/2026025.

Keywords

Space weather, solar storms, aviation safety, cosmic radiation, atmospheric radiation, aircraft electronics, Single Event Upsets, avionics, polar flight routes, geomagnetic storms, aerospace engineering.