The sky is shared; the law is not: Space Debris and Aviation Safety

By Ishita Mishra (IInd Year Student, Gujarat National Law University)

The airspace above Earth should remain unobstructed for commercial aviation. It should not need to share space with the remains of human space exploration. We have spent decades building a detailed international legal structure around space without once seriously asking what happens when that space comes crashing down to the air that planes fly through.

This question no longer remains abstract. In October 2025, United Airlines Flight 1093, a Boeing 737 MAX departing Denver for Los Angeles, was struck mid-air by an object that impacted the cockpit windshield and caused injuries to a pilot’s arm, forcing an emergency diversion to Salt Lake City. A warning that results in no casualties is simply a close call that the history of flight tells us not to ignore. This is one of those warnings. The question is whether the legal system is capable of treating it as such. The law, it turns out, has not caught up with gravity. What follows is an argument that it needs to, and that the longer the gap between space activity and legal accountability remains unaddressed, the more the question shifts from whether something will go wrong to who will be left holding the cost when it does.

Uncontrolled re-entries

The Earth’s orbit is a crowded highway, with thousands of active satellites competing with the inactive, the spent rockets, and the debris from previous collisions. But most of this debris is not in orbit forever. Eventually, gravity wins. 

And the frequency with which it is winning is increasing. Recent studies have found that the number of uncontrolled re-entries is rising in direct proportion to launch volumes. Given the advent of mega constellations, which are becoming the norm rather than the exception, the skies over commercial air routes are certainly not statistically empty. 

Scientists analysing re-entry trajectories have determined that the debris is increasingly likely to enter heavily trafficked airspace. There is a calculated 26% annual probability of uncontrolled re-entry traversing highly trafficked airspace, and a 75% probability in moderately trafficked airspace.

The probability of debris actually striking an aircraft remains low. Researchers say this consistently, and it is true. But aviation safety has never been about playing probability games. It is about preventing the one scenario that cannot be undone.

Why aviation law cares about low probability events 

The discipline of worst-case thinking serves as the foundation for aviation law. The aviation industry has established commercial flight as its safest transportation method because regulators treat even remote danger situations with intense scrutiny when they involve serious potential outcomes. The system is designed to protect against potential disasters that would occur through failure to follow established protocols. That principle has a legal home. ICAO’s Safety Management Standards (“SMS”), which are consolidated in Annex 19 to the Convention on International Civil Aviation (“Chicago Convention”), require the States to implement SMS because anticipated risks demand structural responses before incidents occur. It does not ask how likely harm is, but rather whether the harm is foreseeable.

Space debris in the air at cruising height is a rare but critical risk. The size and velocity of the object determine the extent of damage, rapid decompression, and engine failure. This risk cannot be addressed through pilots' training and design modifications because it is not similar to birds and turbulence. A falling object with little warning leaves little time for reaction, making it dangerous. To address safety risks, one must take direct actions because it is not possible through operational skills and design modifications.

Airspace authorities acknowledge this implicitly. They respond to this uncertainty by closing sections of airspace during predicted re-entries. The European region experienced a similar incident in 2022 when a re-entry of a Chinese rocket body disrupted hundreds of flights. Such closures are only preventative but prove to be costly and inefficient as their occurrence becomes more frequent. 

The question is not whether this approach is prudent. It is whether this approach is sustainable. And if the answer is no, then what is the legal framework that should exist in its place?

The legal blind spot between air and space

The issue clearly is with the law and not the technology itself. International space law has never addressed the risk associated with commercial aviation, and the Outer Space Treaty (“OST”) of 1967 and the Liability Convention of 1972 codify state responsibility for space objects. But neither defines space debris as a legal category nor provides for economic loss resulting from the adoption of precautions such as closing airspace triggered by uncontrolled re-entries. Under Article VIII of OST, the launching state retains the ownership of its debris, but once that debris becomes uncontrolled, no operative legal rule determines what responsibilities that ownership carries in practice. Article II of the Liability Convention imposes absolute liability on launching states for damage caused on Earth’s surface and damage to aircraft in flight, but airspace closure costs are economic loss, not physical damage. This gap cannot be corrected by creative interpretation; it needs to be structurally addressed.

According to Joshua Tallis, a research scientist at the Centre for Naval Analyses whose work focuses on space governance and strategic competition, the area of space debris is currently in a kind of legal ‘grey zone.’  It is owned indefinitely by the launching state, yet once it becomes uncontrolled, no clear rules govern who bears responsibility for its consequences.  Hence, the choice of uncontrolled re-entry over safer disposal methods disrupts air travel, and the cost of space disarray is borne on Earth.

Soft law, hard consequences

A dedicated body of soft-law instruments addresses space sustainability, yet none carry binding legal force. International bodies have developed non-binding norms like the Inter-Agency Space Debris Coordination Committee (“IADC”) guidelines, the UNCOPUOS, 2019 Guidelines for the Long-Term Sustainability of Outer Space Activities of 2019 (“UNCOPUOS Guidelines”), etc., encouraging debris mitigation, responsible disposal, and better tracking. Many states have ratified and implemented these standards domestically.  

These are based on voluntary compliance, have no enforcement, and lacked input from the aviation sector during negotiations. It is seen as a technical issue in space governance, but as an operational issue in flight regulators, thus the disconnect. Space law looks up, while aviation law looks ahead, and the risk falls through the gap.

What separates this issue from most emerging risks is that it is avoidable at source. Studies show that controlled re-entry into remote ocean areas is technically feasible and already practiced by some space actors. In many cases, the decision not to do so is often driven by cost, convenience, or lack of regulatory pressure rather than technical constraint. In other words, falling debris is not an unavoidable byproduct of space exploration. It is the result of policy choices. 

Toward a more coherent legal response

The way forward does not require new treaties. It does not require new treaties quickly. It does not require new treaties at all. What it does require is a more pragmatic relationship between aviation safety principles and space activity regulation.

First, controlled re-entry should not be a choice but a requirement. If an operator is capable of a safe re-entry, then that operator should not have a choice. As urged in the IADC guidelines and the UNCOPUOS Guidelines, a new treaty is not necessary. What is necessary is a revision of national space licenses to require controlled re-entry.

Second, airspace risk should be a consideration in launch licenses. Airspace risk should be a consideration in launch licenses, not a response to airspace risk after the launch. The way forward is a joint ICAO/UNOOSA working group with a clear mandate to develop re-entry risk standards for launch licenses.

Finally, but certainly not least, the cost factor. In the event that airspace closure is necessary because of the predicted re-entries, it should not all fall on the shoulders of the airlines and their passengers. This can be achieved through the setting up of an industry-wide compensation fund, similar to the International Oil Pollution Compensation Fund, where airlines can make a claim for closure costs directly from the operator's proportionate contribution, rather than through diplomatic action.

Conclusion

Space debris is an environmental and orbital problem, and its effects will soon extend into civil airspace, requiring strict standards for safety. Unless legal principles governing controlled re-entry, cost allocation, and cooperation between space and aviation authorities are developed, the proposed prevention strategies are not likely to succeed. As space activities increase, the challenge is no longer limiting the damage but making legal responsibility and risk coincide. Aviation law has progressed due to foresight or disaster. Space law can afford foresight. Once space debris enters civil airspace, it becomes everyone’s problem.

The sky is shared. The risk is shared. The responsibility should also be shared. Waiting for a fatal accident to prove this would be the most expensive lesson in space exploration.