As the number of satellites in orbit continues to climb, so does the risk of their remnants falling back to Earth, and into the path of commercial airliners. A 2025 study conducted by the University of British Columbia estimates a 26% probability that, within a year, uncontrolled space debris will re-enter Earth\u2019s atmosphere over heavily trafficked airspace. And by 2030, the probability of an individual commercial aircraft encountering a piece of debris could reach 1 in 1,000, based on earlier modeling.<\/p>\n
Why Small Debris Poses Big Danger At Flight Altitude<\/p>\n
The primary threat doesn\u2019t come from large rocket bodies or defunct satellites, but from small fragments that survive atmospheric re-entry. These can range from dust-sized particles to fuel tanks, many of which descend rapidly through the same altitude at which commercial aircraft operate, around 30,000 to 40,000 feet.<\/p>\n
\u201cAircraft can be affected by much smaller pieces of debris. For example, airplanes flying through the ash of a volcano is risky because of the small particles,\u201d explained Benjamin Virgili Bastida, a space debris system engineer at the European Space Agency (ESA). \u201cKind of a similar thing could happen with re-entering debris.\u201d<\/p>\n
These particles pose a unique risk to jet engines, navigation systems, and fuselage integrity. While atmospheric entry typically burns up most of a spacecraft, some elements, particularly metallic and composite structures, can endure, retaining enough mass and velocity to inflict damage.<\/p>\n
Virgili Bastida and his team recently published their findings in the Journal of Space Safety Engineering. Their work focuses on the challenges of determining when and where airspace should be closed due to potential re-entry threats, an issue that becomes increasingly complex as launch frequency rises.<\/p>\n
Lessons From The Long March And The Need For Coordination<\/p>\n
In November 2022, Spain was forced to close a significant portion of its airspace when the core stage of China\u2019s Long March 5B rocket made an uncontrolled re-entry. Over 300 flights were delayed, rerouted, or canceled, as air traffic controllers attempted to mitigate the unknown trajectory of a 20-ton object, one of the largest uncontrolled re-entries in recent years.<\/p>\n
This incident highlighted the current lack of global coordination and limited predictive accuracy regarding space debris paths. As reported by Space.com<\/a>, experts say these kinds of shutdowns may become more frequent, unless more precise forecasting systems and international standards are put in place.<\/p>\n \u201cWhat we are trying to investigate in the studies we are running is to see what is really the threshold for risk for an aircraft,\u201d said Virgili Bastida. \u201cAt what risk should we react?\u201d<\/p>\n The dilemma lies in finding the balance between overreaction and inaction. React too frequently, and commercial aviation could suffer unnecessary disruption; wait too long, and the consequences could be catastrophic.<\/p>\n \u201cIf we react at every risk, half of the world will be impacted every now and then, so it\u2019s not feasible,\u201d Virgili Bastida warned. \u201cDo we react for everything which has a chance to reach the ground? Or do we react only for the very large objects, as we did for the Long March?\u201d<\/p>\n Uncertainty And Delays: The Cost Of Wide Margins Of Error<\/p>\n