Few topics in the field of space law have been as widely debated in the recent past as those of space property rights. The interest is understandable, given that talk of commercial lunar development has been going on for years. Of the several companies with plans to land on the Moon within the next year or two, some intend to eventually set up mining operations. Other companies are raising investment for asteroid mining. A number of countries, including the United States, have set up favorable legal regimes for the extraction and ownership of physical resources derived from space. The United States’ apparent pivot back to the Moon has renewed interest in establishing a long-term human presence on the lunar surface.

Despite the body of work analyzing issues such as space property rights and the notion of territorial appropriation, several outstanding questions may require practical experience to be answered, suggesting the fallibility of regulating too far in advance. The answers to others, however, can be teased out in proposals and ideas that might have future applicability. One such question is of interference in surface activities on other worlds. Can a mining activity on an asteroid or a habitat on the Moon, for example, be protected from interruption or intrusion by a competitor? How might a company ensure that it will have unfettered access to the surface location upon which it has placed hardware, or the resources which may lie within? These are critical concerns for business certainty and investor confidence, as well as continued safety of operations.It may be that many, if not all, of these plans fail to come to fruition in the timelines currently envisioned. Challenging technical, economic, and business hurdles will need to be overcome before commercial space mining or Moon bases begin in earnest. Nonetheless, these proposals are effective catalysts for the establishment of an enabling legal and regulatory environment. Indeed, it seems that policy and regulation for commercial operations on other worlds are outpacing the technologies and activities they intend to oversee.

Established space law does not help the issue. Article II of the Outer Space Treaty prohibits territorial appropriation in outer space by claims of sovereignty or means of occupation. A country cannot simply declare that a plot of land on the Moon or an asteroid is theirs in order to keep others out. By the treaty, a company has no legal right to a location in space, even if it has stationed permanent equipment there. Without a current legal foundation for non-interference in space operations, a solution to emergent issues will need to evolve through state practice and norms of behavior.

One such possible practice may be the concept of a “non-interference zone,” an area around a spacecraft or surface facility in which others may not enter or conduct their own activities. It’s an idea that’s been floated in the United States before, as a part of licensing requirements for operating a non-governmental spacecraft. Nothing about it, as proposed, overtly violates the Outer Space Treaty. Now, with commercial surface activities on the Moon seemingly imminent and the government close to reforming the regulatory regime to enable it, the non-interference zone is a concept that will likely come up again.

This brief essay explores the non-interference zone idea to frame continuing discussions on the topic. As background, it looks at the history of the concept and offers considerations for its implementation—if it is to be implemented. To that, the essay examines whether current proposals to resolve the regulatory gap for “authorization and continuing supervision” of on-orbit space activities are conducive to these zones and offers thoughts on possible developments in the future.


In late 2013, Bigelow Aerospace submitted a request for a payload review of a proposed lunar habitat by the Federal Aviation Administration’s Office of Commercial Space Transportation (AST). Though the company had no immediate plans for a lunar base, it sought to identify any issues that could hinder private development of the Moon. Bigelow asked AST to confirm that no future licenses would be issued that would interfere with the operations of the lunar habitat, seeking the creation of a zone of operation in which other US entities would not be able to enter.

A year after Bigelow’s request, AST issued a reply largely affirming Bigelow’s non-interference zone idea. The letter to Bigelow stated thatThe concept of this non-interference zone has parallels. AST’s licenses already stipulate that payloads not destined for rendezvous with the International Space Station may not enter a 200 kilometer “safety zone” that surrounds the station. The International Telecommunication Union (ITU) allocates orbital slots in geostationary orbit to minimize frequency interference by satellites. While operators of space objects are not, by the Outer Space Treaty, required to abide by ITU’s slot allocations, or foreign governments with the space station’s safety zone, they do so in good faith to minimize risks of collision, frequency interference, and diplomatic incidents. Licensing regimes for non-governmental spacecraft have codified adherence to these non-interference zones as requirements, establishing what amounts to de facto rights to locations in space.

[w]e recognize the private sector’s need to protect its assets and personnel on the Moon or on other celestial bodies. Supporting non-interference for private sector operations will enhance safety and only add to the long history of preserving ownership interests in hardware and equipment. Per Congressional guidance, we intend to leverage the FAA’s existing launch licensing authority to encourage private sector investments in space systems by ensuring that commercial activities can be conducted on a non-interference basis.

In its fiscal year 2016 transportation, housing, and urban development appropriations bill, the House of Representatives’ Committee on Appropriations also endorsed the idea, writing in page 21 of its report that,

[t]he Committee applauds actions taken by the FAA Office of Commercial Space Transportation confirming the FAA’s willingness to leverage its existing launch licensing authority to encourage private sector investment in lunar systems that will work in tandem with SLS and Orion, by ensuring that commercial activities can be conducted on a non-interference basis. The Committee urges the FAA to continue to add details, such as specified zones of exclusive operation on the lunar surface.

Issues of implementation

While straightforward as a concept, the non-interference zone becomes more far more complicated in implementation. The wide variety of objects and possible operations in space suggests that non-interference zones would require significant flexibility instead of being a “one-size-fits-all” standard. The proper scope of non-interference, both in physical space and acceptable activities, would likely differ from space resource to space resource and based on potential conflicting uses and users of a location. The characteristics of a zone—its size and protections offered—would be shaped by several environmental and operational factors that would need to be taken into consideration when issuing a license.

For example, the horizon on the Moon is less than 2.5 kilometers away, while the horizon on a small asteroid may be merely dozens of meters. The likelihood that an activity would interfere with another operation beyond a horizon would be small, suggesting that a non-interference zone surrounding an object would be relative to the size of the body on which its located.

However, depending on the characteristics of the location and the activities taking place on it, interference beyond the horizon may be possible. Dust and debris kicked up from the lunar regolith during excavation may fall a considerable distance from the mining activity, perhaps past the horizon. Perturbances to a small asteroid during mining on one side may affect activities on the other. There is no simple way to reconcile these challenges. Moreover, certain locations are more “valuable” than others; the lunar south pole, for example, contains significant and concentrated water-ice deposits. It will be difficult to protect an object at the pole without establishing de facto claim of rights for its operator on the entirety of the location’s vital resources.

As thought experiments alone, these are complicated issues; as questions that require answers if non-interference zones are to be realized as part of the regulatory regime, they become even more important and troublesome. There are, of course, methods by which they may begin to be tackled. For example, in its endorsement of the non-interference zone concept, AST’s advisory committee, the Commercial Space Transportation Advisory Committee, suggested that a variety of tools, such as probabilistic risk analysis, could be used as a dynamic approach for establishing reasonable zones of non-interference. However, it is likely that these zones would need to be determined on a case-by-case basis, at least in the early years.

Meanwhile, the scope and scale of missions would need to come into consideration. Early missions to the Moon or asteroids are likely to be conducted with small, simple robotic landers or rovers. Space mining or lunar development plans will unfold slowly, with years between the identification of targets, in-situ prospecting, and actual operations. Likewise, creation of a lunar base will take place over a significant span of time, probably beginning with robotic site planning, excavation, and construction before any direct human involvement. While it is surely possible that some level of “interference” could occur between operators during these early stages, it is difficult to qualify all interference as “harmful.” For example, would the operation of two resource-prospecting lunar rovers scouting mining sites at the same location really risk meaningful damage or interruptions in all but the most extreme circumstances, such as a collision? Would the transit of a rover through a static lunar base’s non-interference zone pose a real threat to that base’s operation, except in instances of gross negligence? What “phase” of an activity demarcates its need for more stringent protection in the form of a larger or more restrictive non-interference zone?

This poses its own challenges. Writing at length about how agencies such as FAA establish new regulatory and licensing mechanisms, Laura Montgomery, former manager of the Space Law Branch in the FAA’s Office of the Chief Council, noted that the regime “will evolve over time, but each phase will possess its own burdens.”

When regulating on a case-by-case basis, an agency that seeks to provide the industry some flexibility will try to avoid imposing the same requirements on everyone regardless of their circumstances. However, fairness and the law require that they treat operators doing similar things in the same way. They also require transparency in the administration of a regulatory regime, so operators will need and want to know what precedents have been created by an agency’s treatment of other operators like them. All these good, well-intentioned concerns slow the review process down.

Over time, the regime would mature. As operations evolve and the agency gains experience with activities involved in non-interference zones, it could,

issue regulations that it could apply generally. At the same time, however, they would set those requirements into regulations that would take years to change through rulemaking. If a private operator wanted to do something other than what a regulation required, the operator would have to prove that it qualified for a waiver. This is also a time-consuming process.

As Montgomery argues, regulating new activities in space on a case-to-case basis is a burdensome and time-consuming process, which is itself unconducive to business certainty. However, “[i]f the agency attempted to set standards for activities that had not yet happened, those standards would likely fail to account for lots of variables and unduly constrict what an operator could do.”

The broader context

The non-interference zone idea and its issues of implementation are threads in two larger stories of the United States’ evolving commercial space regulatory regime. The first is expanding that regime to encompass “non-traditional” space activities that fall outside the scope of launch and reentry, remote sensing, and telecommunications licensing. (See: “Seeking regulatory certainty for new space applications,” The Space Review, December 4, 2017.)

While AST’s letter to Bigelow endorsed the non-interference zone, it also noted that the agency did not have the necessary authority to implement it. In particular, the letter highlighted the Department of State’s concern that the commercial space regulatory regime was not equipped to enable the United States’ government to fulfill its Outer Space Treaty obligation of “authorization and continuing supervision” for activities on the Moon and other celestial bodies. To that, AST noted that it was,

committed to working within the federal government to put in place the necessary framework to support such activities and provide Bigelow with the security it seeks to conduct peaceful commercial operations on the lunar surface without fear of harmful interference by other AST licensees.

In the time since Bigelow’s payload review, policymakers have taken steps toward providing a regulatory agency the authority to authorize and supervise non-traditional space activities. One proposal, the “Mission Authorization/enhanced payload review” process offered by the Obama administration and written into legislative language in Rep. James Bridenstine’s “American Space Renaissance Act,” expands AST’s payload review to include licensing commercial on-orbit activities. The other, written into the “American Space Commerce Free Enterprise Act,”(ASCFEA) gives the authority to license on-orbit activities to the Department of Commerce’s Office of Space Commerce (OSC).

These two bills take starkly different approaches on how streamlined and permissive the regulatory environment for commercial spaceflight should be—the other story into which the non-interference zone fits. The ASCFEA is designed as a distinctly and deliberately “lighter” regulatory regime than that in the American Space Renaissance Act, which in turn is modeled off existing practices. ASCFEA’s model seeks to minimize government regulation and oversight of commercial space activities, so as to lessen the burden on commercial operators. Considering Montgomery’s review of burden and challenges posed by the rulemaking process, the impact of these different approaches on the future of the non-interference concept could be significant.

Enabling legislation(?)

To that, what do these pieces of legislation do?

Bridenstine’s bill implicitly endorses the non-interference zone. In the Mission Authorization/enhanced payload review process, approval of a license can be conditioned on a payload’s deployment not resulting “in harmful interference with approved and operating payloads and associated activities.” Presumably, if this regime is instituted, AST would proceed through the aforementioned rulemaking process to define the scope and characteristics of what “harmful interference” entails, effectively establishing non-interference zones around “operating payloads” and their “associated activities.”

Conversely, the authorization and supervision regime in ASCFEA presumes approval of a certificate application without condition. This is unless the Secretary of Commerce, determines, with clear and convincing evidence, that the proposed operation of a space object under an application for certification under this chapter is a violation of an international obligation of the United States pertaining to a nongovernmental entity of the United States under the Outer Space Treaty.

If the Secretary does make this determination, they may “condition the proposed operation covered by the certification only to the extent necessary to prevent a violation of such international obligation.” However, the bill stipulates that the

“Federal Government shall interpret and fulfill its international obligations under the Outer Space Treaty in a manner that minimizes regulations and limitations on the freedom of United States nongovernmental entities to explore and use space.” Moreover, the Secretary of Commerce may not “deny an application for a certification under this section in order to protect an existing certification holder from competition.”

Toward the future

As evidenced by its language, the ASCFEA is not nearly as receptive to the notion of non-interference zones as the American Space Renaissance Act. Indeed, at face value, it appears to prohibit or at least significantly curtail their establishment. Consider that a non-interference zone would likely be a condition placed on an approved certificate: for example, “you may carry out this operation, so long as you remain X meters away from operator Y” or “you may carry out this operation, but you may not carry it out at location X.” The language of the ASCFEA is relatively clear in minimizing limitations such as this, as well as sharply restricting when conditions may be placed. Of course, implementation will come down to how the Department of Commerce interprets and executes the language in statute. It is conceivable—indeed, probable—that a regulatory or legal expert more astute than this author will find a justifiable argument for how a non-interference zone, or something similar, would be possible within the bounds of ASCFEA’s provisions.

As of today, only ASCFEA is up for consideration and potential adoption, as the American Space Renaissance Act has not been reintroduced in the current Congress. ASCFEA passed favorably out of the House of Representative’s space subcommittee in June of 2017, though it has not yet been taken up for a vote on the House floor nor does it have a companion Senate bill.

And so, the idea of a non-interference zone remains simply that, with several outstanding questions still to be answered. Yet, as noted by Mike Gold, who at the time of Bigelow’s proposal was working as the company’s head of DC affairs, “[t]his is the beginning of a process, not the end… this response represents a first step by the AST to use what authority it has to create a safe and attractive environment for commercial lunar development. The first step is always the most challenging…”

As seen, the future of the non-interference zone will depend on the regulatory regime that is ultimately instituted in the United States. It will be informed and shaped by the practice of operating on the surface of other worlds. Its many outstanding questions simply reflect the challenge of regulating—or thinking about regulating—too far in advance. However, as noted at the beginning of this piece, proposals and ideas such as the non-interference zone may have future applicability and can shape thought and discussion for when the time is right to reconsider them.

To that, though this essay focused particularly on issues and context of implementation, there is much more to be said of the non-interference zone idea. For example, it could, if implemented, serve as a framework to minimize interference between international operations on other worlds. It is premature at this stage to delve deeper into the idea, though others have lent their thoughts.

Whatever the future may hold for the idea, it will surely come up again in discussions of how to protect business and investment on other worlds. Considering the progress being made in the development of ever-more ambitious commercial capabilities and plans, those discussions may not be too far away.