The concept of ‘safety zones’ and the possible application thereof to celestial bodies has recently attracted considerable debate, mainly because it constituted one of the elements in the Artemis Accords. Most notably, concerns were raised that the establishment of any such zones would violate the foundational principle of absence of territorial occupation and sovereignty in outer space stemming from Article II of the Outer Space Treaty. The present paper will, first, look into the general approach taken by the Artemis Accords on the issue in the light of the Outer Space Treaty. Second, it will briefly assess more broadly how in other domains concepts of ‘safety zones’ or similar constructs have been developed. This should allow, third, at least for a preliminary assessment of how to ensure that the conditions under which any establishment of ‘safety zones’ on celestial bodies would take place could and/or should be considered legal.

This article studies necessarily conditions to establish reasonable safety zones in outer space. Studies, proposals, an international agreement and precedents in other fields of international law are considered for that purpose. The conclusions include: safety zones should be established for the safety and sustainability of space and restrictions pertaining to safety zones should be equally imposed to all stakeholders; safety zones could be lawfully established when they constitute an essential part of a certain space activity which is in accordance with international law. Elements for a reasonable safety zone also seem to include the implementation of TCBM and the operation in a restricted manner by a State having established one. Appropriateness test should be met in addition to the legality test.

Call it like you want but humanity will soon witness an incredible flurry of activities on the Moon. From governmental plans like the ARTEMIS Program or the International Lunar Research Station (ILRS) to several commercial missions laying the foundations for the development of a lunar economy, more and more actors are targeting our celestial neighbour for future human and robotic exploration. Buzz Aldrin once defined the Moon as a “magnificent desolation”. While this was certainly the case until now, we can be relatively sure that the next individuals to walk on the lunar surface will witness a rather different scenario.
Differently from the past, these new missions will not be finished with planting a flag as they seek to establish an unprecedented network of lunar assets and infrastructures. Due to the physics of the lunar environment, the level of interdependence among actors operating on its surface will grow exponentially with the progressive increase of their number. Most likely, none of them will have the luxury of operating in the “magnificent desolation” witnessed by the Apollo 11 astronauts. In fact, it is becoming more and more apparent that lunar actors will face an unprecedented risk of potentially harmful interference. Even nominal operations such as landing and taking off hold a disruptive potential that might seriously damage or disable assets located in a wide range within the lunar surface. In recognition of this issue, the international community has recently started to debate the concrete usefulness and potential legality of area-based measures to prevent and manage the risk of potentially harmful interference among lunar operations, commonly referred to as “safety zones”.
This paper discusses the practical and legal aspects of safety zones through a dynamic dialogue between an aerospace engineer and a space lawyer. Moving from the current situation for lunar activities, the paper discusses the risks of potentially harmful interference that might be faced by a lunar habitat operator, and consequently assesses the concrete usefulness of safety zones in neutralising them. Building upon these operational considerations, the paper considers fundamental legal aspects of safety zones including their boundary conditions, procedural aspects and substantive legal effects. Merging practical and legal considerations, the paper draws some preliminary conclusions on the potential of safety zones as a policy tool to meet the safety needs of lunar operators in accordance with international law.

The Liability Convention, which establishes the rules for international liability for damage caused by space objects, provides for fault on the side of the damage causer as a condition for compensation for accidents in space. In the absence of the “rules of the road” in space, or at least a common understanding of the standard of care and due diligence, proving fault may become a challenge on the way to obtaining compensation and adequately protecting high-value space assets. In this regard, it can be argued that safety zones established around the locations of space activities can reduce the risks of accidents, while space actors’ conduct in such zones can be an indicator of the presence or absence of any degree of fault. This article analyses the current liability regime applicable to accidents in space and examines whether controversial safety zones can close legal gaps and contribute to the development of space activities.

There is no doubt that the concept of safety zones in outer space embraces the safety of activities in space but discourages any notion of space hegemony. This idea has already found application in providing clear space or separation for safety in aviation, safe distance at launch pads, and safety bubbles for conjunction assessment around spacecraft. Another analogy is the no-fly zone or Air Defense Identification Zone (ADIZ), sometimes established unilaterally. The differences among the analogies lie in their operational nature. An object-centric safety zone, such as separation or a bubble, can be seen as an extension of the current operation of spacecraft where established practices exist. The other is an area-centric zone, no-fly zone, or ADIZ, a novel concept applied in outer space; it requires deep scrutiny. This paper discusses the legality of the two types of safety zones under the UN Space Treaties, inter aria, regarding the rights and obligations specified in Article IX of the Outer Space Treaty (OST). Establishing a safety zone can be interpreted as a declaration of hazardous activities by the establishing State. In theory, the state establishing the safety zone acts as the area controller of the ADIZ and deny entry to the zone. This may be unacceptable under OST Article 2. Even in an area-centric safety zone, the innocent passage of another state’s vehicle through a zone should be granted. In other words, a safety zone needs to be an area without a general coercive authority. Consequently, Article IX is the only requirement imposed on a State to establish a safety zone. This Article imposes the obligation of consultation of the state conducting space activities potentially harmfully interfering with another state’s activities. The Article also acknowledges the right of the affected state to request a consultation with the conducting state. Through a conceptual analysis of the legality of acts of those players, this paper describes the burden of risks of the state establishing the safety zone and the state passing through them. The final goal of this paper is to identify legally desirable conditions for establishing and operating safety zones in outer space.

This contribution proposes a taxonomy of restrictive properties of safety zones in outer space. Based on similar phenomena mainly in the regulation of airspace and the high sea, and with consideration of existing discourse with respect to safety zones in outer space, six main aspects of safety zones that determine its constraining effect on other space actors are identified. Consequently, this paper proposes a dynamic minimality principle when considering how to scope and size a safety zone along the axes of restrictions outlined in the taxonomy.