Space Sustainability in Earth Orbits: A Multidisciplinary Approach to Identify and Mitigate Economic,Operational,and Technological Risks of Active Debris Removal Solutions

Abstract

The surge in launch traffic to low Earth orbit (LEO) is driven by its role as a critical infrastructure for the space economy. As commercial use of LEO expands, concerns about space environment sustainability and space debris are growing among policymakers, private companies, and public institutions. Solutions to address orbit overcrowding, such as active debris removal (ADR) technologies, have been explored, but there is no legal framework assigning responsibility for debris removal. The adoption of these technologies raises concerns about accidents, instability, and mistrust, with potential national security implications, especially since some ADR methods could be repurposed for anti-satellite operations to harm space assets. This article applies a technology assessment methodology to evaluate the risks and attractiveness of these technologies. It analyzes current and emerging solutions for debris removal and monitoring, assessing the associated economic, political, and security risks. It also provides public recommendations to promote the safe, secure, and sustainable use of these technologies while addressing the identified risks.

Keywords

space sustainability active space debris removal dual-use technology space policy and regulation technology assessment

INTRODUCTION

The exploration and utilization of space have undergone rapid expansion in recent years, leading to an exponential increase in the number of objects orbiting the Earth,¹ including space debris. In low Earth orbit (LEO), countless defunct satellites, exhausted rocket stages, and fragments derived from in-space collisions pose a significant threat to spacecraft operation. As the space environment around the Earth becomes increasingly congested, the risks associated with debris’ occupancy become a subject of concern for policymakers, public actors, and private companies.

Recognizing the urgency of the situation, numerous solutions are being developed such as active debris removal (ADR) systems, in-orbit servicing (IOS) technologies, and monitoring systems.

However, space is also a strategic domain for countries worldwide, and it is becoming increasingly contested. The importance of space can be framed along three main dimensions: commercial benefits, national security applications, and scientific or civil contributions. While this work focuses on the commercial and security implications of dual-use ADR technologies, we acknowledge that space also provides substantial scientific and civil benefits, including research, exploration, climate monitoring, and disaster response.

Additionally, in this regard, some countries have also started to study and perform more aggressive activities, such as anti-satellite tests (ASAT). Such activity is undertaken to render nonfunctional enemy satellites in space or even to destroy them. Prominent examples include China’s testing of the FY-1C weather satellite in 2007,² India’s PDV MK-II mission in 2019,³ and Russia’s testing of the DA-ASAT system in 2021.⁴ Until now, this kind of activity has always been performed on its own satellites, thus having a capability demonstration goal only. Still, it remains one of the most notable instances of space technology that could potentially be employed for hostile purposes and so with a dual use. In December 2022, the UN General Assembly passed a resolution calling on states to refrain from conducting debris-producing direct-ascent ASAT weapon tests, a measure intended to mitigate the most harmful demonstrations without imposing a categorical ban on all ASAT activities.⁵

Moreover, policymakers are interested in this matter. The Guidelines for the Long-term Sustainability (LTS) of Outer Space Activities⁶ represent an effort to align all interested stakeholders on a series of best practices that can help in maintaining the orbital environment usable, available, and sustainable in the short, medium, and long term. In contrast, while the LTS guidelines provide an overarching governance structure, other initiatives, such as the Consortium for Execution of Rendezvous and Servicing Operations (CONFERS), have more directly addressed policy-relevant aspects of on-orbit servicing and debris removal by promoting technical and operational standards for safe and transparent rendezvous activities. In general, this refers to policy frameworks, safety of operations, international cooperation, and scientific development; regrettably, they do not make direct reference to dual-use solutions for in-orbit debris removal, hence ending up being less relevant to ADR or IOS activities and potential actors.

Indeed, while their primary objective is to ensure the safety and sustainability of the space environment, and they possess the knowledge associated with the design, development, and operativity of specific technologies, dual-use aspects have remained unexplored, including the overall assessment of different methodologies of ADR. The main objective of the present article was to contribute to filling this knowledge gap and to support discussion on how to guarantee the safety, security, and sustainability of the space environment, addressing the needs of both the commercial sector and national defense interests. In particular, the main original contributions of the present article are: -

Provide an assessment of the risks and key vulnerabilities associated with ADR technologies for which sufficient data exist, establishing clear traceability between policy-level risks and the technical characteristics of each technology.

Advance the state of the art in technology assessment (TA) by adapting a validated weighted star-plot framework, previously applied in ADR studies,^7,8 and extending it to potential ASAT misuse scenarios, thereby prioritizing technology characteristics relevant to operational and policy concerns.

Establish a framework for public recommendations on how to implement the identified technologies while mitigating associated risks.

The “TA and Research Context” section introduces the TA and the research context. The “Survey and Evaluation of ADR Technology” section discusses the ADR technologies. The “Star-Plot Model Definition” section shows the methodology adopted for technology evaluation. The “Results” section shows the results, and finally, the “Discussion and Recommendations” and “Conclusions” sections contain some conclusive considerations.

TA AND RESEARCH CONTEXT

Currently, there are more than 30,000 orbital debris objects, orbiting the Earth, encompassing a cumulative mass exceeding 10,000 tons, and pertaining to a variety of categories¹ as shown in Figure 1. The escalating proliferation of these objects in space raises the ominous menace of a chain of space collisions (Kessler Ssndrome)⁹ and poses a substantial hindrance to the future deployment of satellites. Figure 2 shows the number of conjunction events that a typical satellite at different attitudes can expect in 1 year, showing a clear peak in satellite concentration between altitudes of 500 and 600 km, where indeed two-thirds of all active satellites are currently located.¹ While this region illustrates the extent of orbital congestion, ADR activities are generally expected to focus even more on higher orbital regimes, where debris lifetimes are longer and the consequences of fragmentation events more enduring.

Fig. 1.

Evolution of the number of objects in geocentric orbit by object class. Source: (3).

Fig. 2.

Number of conjunction events that a typical satellite at different attitudes can expect in 1 year. Source: (3).

In this context, ADR technologies emerge as necessary solutions, and the understanding of their dual-use nature demands a structured evaluation framework for TA.

Indeed, over the last few decades, TA has emerged as a growing area of research within many fields, including management and business. This section outlines the approach adopted for TA and shows how it can be utilized to inform policy recommendations, including the research context in which it is applied.

TA Scope as a Tool for Policy Recommendation

TA refers to the proactive identification and evaluation of potential impacts stemming from technological advancements and their applications, but in the full development of its process, TA serves as a valuable resource for policymakers and decision-makers by offering insights that extend beyond specific contexts. Moreover, TA encompasses both efforts to anticipate future developments in technology, including its interactions with markets and society, and the integration of these anticipations into decision-making processes.¹⁰

TA research topic underwent its establishment process following the rapid development in scientific and high-tech sectors around the 1960s,¹⁰ and by the 1980s, it had already been established as an academic area of research.¹¹ In particular, TA embodies a dual role, serving both as a scientific endeavor and as a tool for policy making.¹² Based on the different angles of impact analyses, multiple methodologies and approaches can be used to assess the consequences of technological advancements in various contexts, hence providing scholars and policymakers with tools to approach the analysis of a technology’s development, design, and practical implementation.¹¹

Among the variety of approaches that pertain to TA techniques, a specific strand precisely regards the analysis of technologies inside a given sector. In this strand, TA is a tool for evaluating the appropriateness of a new project, product, or technological capability, with the main goal to connect the analysis to public interests and sector-related policies.

While sharing this perspective, the present work has a dual goal: on the one hand, it aims at contributing to the stream that oversees TA as a method to inform policymakers and is then focused on the public recommendations’ field; on the other hand, it wants to enrich the discussion around appropriate and effective methodologies to conduct a TA activity for policy advice. In particular, the latter concept will be explored, thanks to the development of a model for the assessment of in-orbit dual-use technologies like the ones employed to perform ADR or IOS activities. Even if the application sector is very specific, and insofar minorly explored, this work can anyway count on some contributions that suggest directions for further development.

Research Context

Existing contributions on TA for dual-use scope focus around three main topics.

First and foremost, it has been focused on the technical evaluation of dual-use technologies and on the resulting considerations on whether such technologies may be able to procure harm to other space assets, and with which degree of easiness. The potential risks of ADR technologies have been measured,¹³ including their potential role as ASAT tools. Furthermore, the article provides suggestions to the policymakers on how to ensure a peaceful context for the execution of in-orbit clearing operations.

Our present work is well aligned with this contribution,¹³ and it aims at further expanding the scope of this research stream by proposing the establishment of a model for risks and technologies’ analysis. A further investigation of the potential misuses of ADR, IOS, and rendezvous and proximity operations (RPOs) technologies has been presented.¹⁴ Differently from previous contribution¹³ but in line with the research scope of our work, the authors propose recommendations to mitigate identified risks, at a public and at a private level. The article’s strength stands into a first conceptualization of an economically, legally, and politically viable ADR option, hence expanding the scope to nontechnical factors.

The second most developed topic in literature regards legal approaches, gaps, and regulation needs on the issue. A legal approach to the dilemma around ADR may consider several items, such as cooperation possibilities, theories for disputes resolution, regulatory gaps, and international agreement proposals.¹⁵ Exploring the legal framework surrounding ADR technologies and the potential risks they pose in terms of weaponization, the existing international laws and treaties offer insights into the legal discussion on how to balance the peaceful use and potential weaponization of ADR systems. In a similar fashion, it is shown how a link between regulation needs and governance mechanisms at the public–private level can be created to ensure the safe and effective implementation of debris removal technologies.¹⁶

Regulation alone may be unable to solve the ADR dual-use issue in this regard,¹⁶ and in conclusion, it might be desirable to establish a new international regulatory framework coupled with an organization responsible for the correct management of ADR and IOS operations.

Third and last, a part of the literature focuses on policy interventions aimed at preserving the space environment for the benefit of humankind. On the side of policy tools, a set of approaches, including regulatory measures, cooperation mechanisms, incentivization strategies, international treaties, and practices, are considered effective.¹⁷ Strengthening international agreements and norms to prevent misuse of already active dual-use technologies is proposed as the most important tool at the disposal of the policymaker.¹⁸ In proposing measures to enhance the security and accountability of ADR, IOS, and RPO missions, the recurrent suggestion is to improve monitoring systems, information sharing mechanisms, and protocol standardization.¹⁸

While these contributions provide valuable insights into evaluating and mitigating risks, they do not go deeper into the analysis of technical factors or into risk assessment for a specific scenario. We address also these gaps and fragmentation by providing an interdisciplinary approach to the ADR/ASAT context. In particular, the evaluation and comparison of ADR technologies as potential dual-use ones are conducted using a weighted multicriteria decision-making approach through a star-plot model. Several axes are radiating from an origin, where each axis represents a specific evaluation metric. By connecting the weighted value along each metric axis with straight lines, a star-like figure is obtained, and its area is evaluated.

This procedure is inspired by previous works^7,8 with proper differences. First, the scope of their work is limited to ADR technologies for pure debris removal while we include the potential of their dual-use characteristics. Indeed, in these previous works,^7,8 there is a predefined set of physical characteristics without accounting for this implication or for broader policy tools. Moreover, in one work, just five ADR technologies are analyzed,⁷ while in the other one, a weighted approach is missing, and each metric is considered of the same importance.⁸

Building upon these approaches, our methodology expands the state of the art by considering a broader set of ADR technologies and a larger number of mission-level criteria, incorporating for the first time both physical characteristics and policy tools into the evaluation framework. Traditional metrics such as cost and performance are combined with dual-use factors, such as the contact method. Our methodology improves upon established approaches by ensuring objective and tailored decision-making by employing weights on each category value that dynamically adapt to mission-specific use cases. Finally, another main contribution stands in the discussion on the results in terms of public recommendations for ADR technologies, considering also its evolving nature, to foster awareness and discussions on this delicate topic.

SURVEY AND EVALUATION OF ADR TECHNOLOGY

The core objective of ADR is to enable the de-orbiting of orbital debris, ultimately guiding them toward re-entry into Earth’s atmosphere for controlled destruction. Based on the context of ADR for de-orbiting, in this section, we provide an ADR strategy classification for subsequent evaluation.

First, when referring to space debris, it is common to distinguish between cooperative and noncooperative client objects, although a universal consensus on definitions has not yet been reached. In general terms, cooperative ADR involves situations where the client operator consents to or participates in the mission, for instance, by providing control authority, telemetry, or technical documentation of the spacecraft. Noncooperative ADR instead occurs when such participation is absent. By contrast, the hardware configuration of the target, such as the presence of docking plates, grappling fixtures, or visual fiducials, is often described as prepared versus unprepared. This distinction, also emphasized in European Space Agency’s technical framing of ADR, highlights the fact that both operator involvement and spacecraft design must be considered when classifying targets. Ambiguous middle cases still exist, such as derelict satellites whose operators can no longer control them but are able to provide historical schematics or imagery, showing that the lexicon in this field is still evolving.

In addition, ADR strategies are often described as active or passive; this binary distinction should be treated with caution. The operational concern does not lie strictly in whether a system relies on an active mechanism or a passive augmentation, but rather in the fact that once deployed, many technologies could in practice be adapted to operate across this spectrum. This active–passive framing remains analytically useful but is insufficient on its own to capture the dual-use risks that emerge from technologies capable of flexible engagement profiles once on orbit.

From a dual-use perspective, our analytical focus centers on active ADR approaches. Within this context, a servicing satellite possesses the potential to engage with various space objects, including both operational satellites and debris, throughout contact or contactless phases. It is noteworthy that our analysis exclusively examines individual technologies rather than combinations thereof. This choice was made to ensure analytical clarity and comparability across different ADR concepts. Evaluating each technology in isolation allows for a first-order assessment of its intrinsic characteristics and associated risks, without introducing the additional variability that arises from operational synergies or combined architectures. While this approach simplifies the representation of complex operational scenarios, it provides a consistent and transparent basis for comparison, which can later be refined through more integrated assessments.

Active ADR with a contact phase may encompass a capture phase, which can adopt either a rigid or flexible approach. The former involves the utilization of single or multiarm manipulators, tentacles, or tethered nets, while the latter incorporates methods such as harpoons and tethered space manipulators. The servicing satellite becomes a single complex with space debris, moving it toward the atmosphere. Other technologies with a contact phase may not require direct capture, such as the expanding foam, behaving as a drag-augmentation strategy. In this way, space debris would have a larger effective area, increasing the aerodynamic drag and so speeding up the de-orbit.

In contrast, contactless ADR methods do not involve physical contact with the target objects. These methods encompass the utilization of space-based technologies such as lasers, ion beams, electrostatic forces, and geomagnetic propulsion. This methodology transfers momentum onto the debris, shifting its orbit into a de-orbiting one.

In addition to these categorizations, a useful tool for visualizing ADR strategies concerning their energetic interactions between servicing satellites and targets is the Energy Transfer Class (ET-Class)¹⁹ classification, which can be broken down as follows: -

ET1—Potential Energy Dissipation.

ET2—Impact Energy Dissipation.

ET3—Neutral Energy Balance.

ET4—Destructive Energy Absorption.

Figure 3 shows the classification of the ADR technologies that are considered in this analysis according to a previous work,⁸ which classifies each technology by its main strategy, being capturing removal, propulsion, or drag-augmentation de-orbit. Not all ADR technologies surveyed in the literature have been included in our comparison. We deliberately excluded certain concepts that do not raise clear dual-use concerns or that remain too undeveloped to support a structured analysis. Within the propulsion de-orbit class, we did not consider solar radiation pressure concepts, as these rely on passive environmental forces without an external action. Within the drag-augmentation de-orbit class, we excluded inflatable de-orbit devices, electrodynamic tethers, drag sails, and artificial atmospheric techniques, since these are mounted on the spacecraft itself and require implementation at launch. Moreover, inflatable devices and drag sails could, in principle, operate as externally attachable de-orbit kits. Nevertheless, they are currently integrated into the satellite, and they are designed primarily for self-deployment. Since our scope is to investigate how existing ADR methodologies could be repurposed for ASAT applications, we do not include this option here. However, we note this as a potential avenue for future work, should further data and technological developments allow a more informed assessment of this option.

Fig. 3.

Active debris removal methods subdivided into three main categories.

Indeed, our focus remains on those ADR methods that combine sufficient technical maturity with the possibility of being adapted to deliberately harmful applications. Finally, Table 1 synthesizes the technologies shown in Figure 3, presenting their classification and ET-C, while Figure 4 shows schematically the working principle of each described technology.

Table 1.

Description of the Active Debris Removal Methodologies Considered with Indication of Active Debris Removal Class and Energy Transfer Class

Technology	TRL	ET-Class	ADR Class	Description (Source)
Single-arm grab capture	4	2	I	A single-robotic manipulator arm grabs debris with a grasper end effector.^20–23
Multiarm grab capture	4	2	I	The concept is the same as a single-arm grab capture, with the advantage of multiarm coordination.^24–26
Magnetic arm capture	6	3	I	A robotic manipulator arm adheres to debris with a magnetic end effector.²⁷
Tentacle-arm capture	6	2	I	Multi-robotic manipulator tentacles that surround the debris.^28,29
Tethered nets capture	6	2	I	A flexible net is shot onto the debris with a large deployment area.^30–32
Harpoon capture	6	2	I	A harpoon device is shot into the debris.^32–34
Tethered space manipulator capture	5	2	I	A space tether is used as a flexible arm to get the debris.^35–37
Laser propulsion	4	4	II	A system sprays a laser beam onto the debris.^38,39
Ion beam propulsion	4	1	II	A system sprays an electrically neutral high-speed ion beam onto the debris.^40–42
Electrostatic forces propulsion	2	1	II	A system decelerates the debris through charge in space plasma.^43–45
Geomagnetic propulsion	1	1	II	A system generates a geomagnetic torque on the debris.^46–48
Expanding foam drag-augmentation	4	1	III	A foam is sprayed onto the debris.^49–51

ADR, active debris removal; ET-Class, Energy Transfer Class; TRL, Technology Readiness Level.

Fig. 4.

Capture: (a) single-arm grab, (b) multiarm grab, (c) magnetic grab, (d) tentacle-arm grab, (e) tethered nets, (f) harpoon, (g) tethered space manipulator. Propulsion: (h) laser, (i) ion beam, (j) electrostatic forces, (k) geomagnetic. Drag-augmentation: (l) expanding foam.

STAR-PLOT MODEL DEFINITION

The star-plot model employs several axes radiating from an origin, with each axis representing a specific evaluation metric. The number of axes represents the key indicators that have been selected as the evaluation items. Then, it involves comparing the indicator criteria between themselves to determine their relative importance values and, so, assigning a certain weight between 0 and 1, according to the comparison scenario chosen. To determine the composite scores for each ADR method, the following scoring formula is employed:

C S_{i} = \frac{E A_{i}}{E A_{\max}},

where

C S_{i}

represents the composite score for a given technology,

E A_{i}

is the envelope area derived from the reference star-plot for that technology, and

E A_{\max}

corresponds to the maximum achievable envelope area attainable when one technology achieves the maximum score in each parameter considered.

This formula allows for the quantification of the performance of each ADR method within the context of the defined evaluation items and criteria. It provides a valuable means of comparing and ranking the ADR methods based on their overall effectiveness and suitability for specific space debris scenarios.

Indicator Criteria

Specific indicator criteria are defined, including both physical and dual-use factors, which are subject to weighting based on the applicability of the technology to the selected use case. The core variables are outlined as follows, with each variable assigned a range between 1 and 3, which reflects the level of awareness required: 1.

Readiness: It gauges the developmental stage of one technology and its proximity to adoption. It can be effectively summarized by using the Technology Readiness Level (TRL) indicator or its derived elaboration.

1. 1–2; 2. 3–4; 3. 5–9.

Proficiency: It qualitatively describes the operational efficiency of a technology in terms of the potential debris generation during the removal operation. It can be associated with the ET-Class of one technology.

1. ET-1 and ET-3; 2. ET-2; 3. ET-4.

Technical Simplicity: It assesses the complexity of a technology in terms of the adoption of passive or active mechanisms, which may or may not require control before the de-orbiting phase.

1. Active; 2. Partial passive; 3. Passive.

Development Costs: It represents qualitatively the cost of the level of financial resources required for the advancement of a technology.

1. High; 2. Medium; 3. Low.

Orbital Operational Range: It characterizes the orbital environment within which the technology is designed to operate or the maximum altitude to which it is engineered to function.

1. Up to 2,000 km; 2. Up to 11,000 km; 3. Up to 36,000 km.

Debris Size Range: It defines the maximum size of debris that technology can capture or manage.

1. ≪ 1 m; 2. ≈1 m; 3. ≫ 1 m.

Physical Approach Mode: It elucidates the nature of the contact relationship existing between a given technology and the target debris.

1. Rigid; 2. Flexible; 3. Contactless.

This methodological structure aligns with best practices identified in recent literature on TA,⁵² which highlights the value of employing multiple indicators, real data, and simple scoring systems to enhance robustness and interpretability. Furthermore, its generalized formulation ensures applicability to a broad range of ADR technologies, thereby contributing to the overall strength of the assessment.

The characteristics considered can provide the basis to evaluate how each technology may impact broader outcomes in space operations. In the context of ADR technologies, these features can be directly associated with four primary categories of concern defined as operational, technological, political, and economical risks. Together, they capture the main dimensions through which ADR systems may influence space safety, security, and governance. Specifically:

Operational Risk: captures the direct functional impact on space assets, such as accidental collisions, failed capture attempts, or the generation of new debris that could compromise the safety of the orbital environment.

Technological Risk: arises from failures, design flaws, or unforeseen technical interactions, such as loss of control, software or guidance errors, or structural malfunctions, that could produce cascading effects or undermine confidence in ADR technologies.

Political Risk: emerges when the deployment or use of a technology, whether deliberate or perceived, could escalate diplomatic tensions, provoke arms-race dynamics, or trigger international responses, particularly in cases where the system’s dual-use potential is unclear.

Economical Risk: concerns the direct and indirect financial costs associated with the development, deployment, and operation, including potential mission failures, loss of investment, increased insurance premiums, or the creation of market barriers that could disadvantage smaller or emerging space actors.

Hereafter, in Table 2, the key points of the selected indicator criteria are highlighted and the rationale for the risk associated with each of them.

Table 2.

Key Points of the Selected Indicator Criteria and the Rationale for the Risk Link

Characteristic	Key Point	Rationale for Risk Link
Readiness	Reliability	A higher TRL means that the technology is fully proven and easily deployable, making its successful use or misuse more probable and its consequences more far-reaching.
Proficiency	Potential damage	Higher proficiency is directly correlated with the potential damage the technology can cause to nearby satellites, increasing operational disruption, economic losses, and the likelihood of political tensions.
Technical simplicity	Operability	Increasing simplicity lowers the technical barriers to operation, enabling a wider range of actors to employ the system and reducing safeguards against misuse.
Development costs	Accessibility	Lower costs make the technology affordable to more developers and operators, multiplying the chances of uncontrolled deployments or poorly regulated applications.
Orbital operational range	Reach coverage	Wider operational reach exposes a broader set of orbital regimes and satellites, expanding both the number and diversity of targets that could be affected.
Debris size range	Capacity	Technologies able to handle large debris could be repurposed to threaten large satellites, increasing potential economic damage.
Physical approach mode	Intrusiveness	Contactless methods cause higher technical and strategic risks, as they can operate remotely without physical attachment, potentially influencing multiple objects within range.

The metrics selected for this evaluation are not arbitrary but reflect the dimensions that directly influence whether an ADR technology could realistically be repurposed in line with the two ASAT use cases. For instance, readiness (via TRL) is critical to determine whether a system could be deployed rapidly in a crisis. By contrast, orbital operational range and debris size range are more relevant when the mission is engineered against a known target with specific orbital parameters. Larger debris often indicates intact satellites, which, under dual-use conditions, could involve the deliberate disabling of operational assets. A wider orbital operational range consequently broadens the set of satellites that may be targeted.

Similarly, proficiency and physical approach mode capture the extent to which a technology can inflict disruption either diffusely or selectively. These indicators have also been emphasized in prior technical assessments of ADR and proximity operations as key factors in determining operational viability and potential misuse.

In general, the indicator criteria should also consider other aspects, for example, operational challenges (such as fuel consumption, communication, and power), duration, deployment complexity, maintenance requirements, and cybersecurity risks, which can, in principle, be modeled with established astrodynamics and engineering methods. However, doing so would require moving beyond a technology-level comparison and instead constructing candidate multitechnology mission concepts, selecting propulsion systems, transfer strategies, and operational profiles. Such an approach would result in a fundamentally different type of analysis, more technical in nature and less directly aligned with our objective of evaluating dual-use risks and policy-level implications. Moreover, there are also still insufficient data for all ADR technologies to address a comparison in this sense, leaving this an evolving evaluation, which will go deeper once the level of maturity, integration, qualification, verification, and testing reaches a higher step.

Use Cases Description

In this study, we define two complementary ASAT use cases that illustrate how technologies originally designed for ADR can be repurposed for hostile or dual-use activities. These scenarios are grounded in real developments in military space capabilities and mirror the way actual decision-makers could frame strategic goals of space denial or control.

ASAT Use Case 1: The objective is to induce diffuse damage without a specific predefined target and at minimal time.

ASAT Use Case 2: The objective is to induce damage upon a specific predefined target in space, without any temporal constraints.

The first case refers to a situation in which the goal is to generate diffuse damage in orbit without selecting a specific satellite in advance. The reference to “minimal time” should be understood as minimal development and deployment time, that is, the speed with which a technology can be readied for use, rather than the in-orbit duration of a mission or the time required to reach or engage a target. The intention is not to destroy a single object but to degrade the stability, safety, or usability of an orbital region as a whole. This can take the form of increasing collision risks, forcing constellations into repeated avoidance maneuvers, or undermining the operational reliability of space services. A concrete example would be interfering with large-scale commercial constellations that provide global communications, so as to disrupt civilian and military networks during wartime. Another example would be targeting Earth observation operators, deliberately creating operational hazards that reduce the quality and availability of data in a crisis. In this use case, the emphasis is on acting quickly with readily available means, minimizing attribution, and maximizing environmental and operational uncertainty. Readiness and deployability are central, while the duration of the orbital presence is secondary.

The second case addresses a more deliberate and targeted approach in which a specific satellite is identified in advance as the sole focus of the mission. The aim is to disable, degrade, or capture that asset for clear military or intelligence purposes. This may include striking an early warning satellite, neutralizing a secure communication node, or removing from service a high-resolution imaging platform. A relevant example is the targeting of a military command and control satellite in geostationary orbit or the removal of a single element of a strategic constellation, which can undermine the adversary’s ability to coordinate operations. In this case, the mission may be prepared over months or years, with time not being a constraint. What matters most are reliability, mission success, and stealth.

These two cases were not selected to be exhaustive, but because they reflect the two principal choices an actor repurposing ADR technology would realistically face, either acting against a group of targets or acting against a single predefined one. Time then becomes a second, critical dimension that can reshape either option. For example, inducing diffuse damage as quickly as possible may require sacrificing target specificity, while disabling a predefined asset may call for a more deliberate approach to ensure the intended effect. Other combinations are clearly possible, such as diffuse damage without temporal constraint or the rapid neutralization of a single target, and the framework can accommodate them.

Indeed, the use cases are intended as illustrative examples, and they do not cover the full range of possible ASAT strategies. Other scenarios could emerge depending on political aims, technological maturity, or operational context. However, the framework itself is adaptable since it uses different weights to test and evaluate a wide range of tailored use cases, including specifically those developed in direct consultation with specific stakeholders to reflect their operational or policy concerns.

Weights and Scores Assignment

The weights assigned for each parameter are defined in Table 3 and come from the consideration of each use case statement. Use Case 1 requires a functioning technology with limited economic and operational constraints to be ready in a brief time. This suggests that readiness, development costs, and technology simplicity have high priority. Then, since the objective is to create as much damage as possible, the way of creating diffuse damage is preferred, especially in a contactless approach. This is not because contactless approaches are intrinsically more destructive but because the operational objectives and incentives of this scenario favor methods that enable operations while avoiding being involved and maximizing the effect.

Table 3.

Assigned Weights for the Two Use Case with Indication of the Relative Parameter ID

Weight	Use Case 1	Use Case 2
Weight	Parameter ID	Parameter ID
1/7	6	2
2/7	5	7
3/7	7	3
4/7	2	4
5/7	3	1
6/7	4	6
1	1	5

In this way, proficiency and physical approach mode has a medium priority. Finally, since there is no predefined target, the damage can be to any subsystems and with a variable level of success. Furthermore, the debris can be in any orbital regime and of any size. Indeed, the operational risk, debris size range, and orbital operational range have low priority.

Instead, for Use Case 2, the target is defined and so its orbit and dimensions. This sets the debris size range and orbital operational range with high priority. Then, since it is not required that the technology is currently operating, it leaves time for further development, also in terms of cost, simplicity, and level of success. Indeed, readiness, development costs, technology simplicity, and operational risk have medium priority. Finally, during the operation, the damage can be induced with any methodology, given that physical approach mode and proficiency have low priority.

The weights in Table 3 are expressed in a rank-ordered form to illustrate relative prioritization across criteria for each use case. This was chosen as a simplifying assumption to maintain comparability and transparency across technologies. We acknowledge that in practice, different parameters could carry equal weight, or some might be deemed irrelevant depending on the actor’s intent and mission concept. While exploring such refinements lies beyond the scope of this work, this framework is flexible and could accommodate them in future extensions.

To fulfill all the prerequisites essential for the analysis, the final step entails the assignment of scores for each technology. The values have been evaluated and quantified by the authors based on analyzing models provided in the references pertaining to each technology reported in Table 1 and on the current ADR technologies comparison state of the art.^7,8 Then, they will undergo normalization to a total sum of 1, thereby ensuring that 1 represents the maximum attainable score for each respective category, before the application of weighting factors. The unweighted scores are reported in Table 4.

Table 4.

Unweighted Scores Assigned to Each Technology for Each Parameter

Technology	ID 1	ID 2	ID 3	ID 4	ID 5	ID 6	ID 7
Single-arm grab capture	2	2	1	1	3	2	1
Multiarm grab capture	2	2	1	1	3	2	1
Arm magnetic capture	3	1	1	1	3	2	1
Tentacle-arm capture	3	2	1	1	3	2	1
Tethered nets capture	3	2	1	3	3	2	2
Harpoon capture	3	2	1	3	3	2	1
Tethered space manipulator capture	3	3	1	1	3	2	2
Laser propulsion	2	1	2	1	3	1	3
Ion beam propulsion	2	1	2	3	3	3	3
Electrostatic forces propulsion	1	1	2	2	1	1	3
Geomagnetic propulsion	1	1	2	2	1	3	2
Expanding foam drag-augmentation	2	1	3	3	1	3	2

RESULTS

In this subsection, we present the star-plot results. The graphical representations in Figure 5 illustrate, for each technology, three star-plot for, respectively, no use case (unweighted), Use Case 1, and Use Case 2.

Fig. 5.

ADR technologies star-plot for unweighted and use cases. Capture: (a) single-arm grab, (b) multiarm grab, (c) magnetic grab, (d) tentacle-arm grab, (e) tethered nets, (f) harpoon, (g) tethered space manipulator. Propulsion: (h) laser, (i) ion beam, (j) electrostatic forces, (k) geomagnetic. Drag-augmentation: (l) expanding foam. ADR, active debris removal.

It is shown how the applied weights influence the shape of each star-plot, thereby offering an assessment of each technology’s suitability for the specified use case. As previously mentioned, a more comprehensive evaluation is derived from the final composite scores $C S_{i}$ of each technology, shown with bar diagrams in Figures 6 and 7. This provides an initial hierarchical ranking, facilitating regulatory evaluation considerations.

Fig. 6.

Comprehensive scores for Use Case 1.

Fig. 7.

Comprehensive scores for Use Case 2.

DISCUSSION AND RECOMMENDATIONS

Captured technologies, with a specific focus on tethered net system and harpoon, consistently exhibit high scores in our evaluation for both use cases, then expanding foam especially suits Use Case 1 while ion beam propulsion stands out for Use Case 2 because its operational principle allows for contactless, continuous force application over time, making it especially suitable for acting on intact satellites in known orbits, while it would be less practical for creating diffuse damage across multiple targets.

It is essential to emphasize that the prevalence of technologies characterized by a high TRL that do not attain notably high scores in the results serves as a conspicuous indicator that, presently, these technologies are not predominantly aligned with the concept of dual use. Also, some technologies may not perform optimally in either use case and that is mainly because they may not be mature.

Both the technical aspects of the examined technologies and the methodology adopted offer a wide spectrum of perspectives from which the ADR systems can be examined, and consequently, a range of options for judgment.

A first notable consideration emerging from the results regards the set of technologies that employ a capture method, namely the tethered space manipulator, the tentacle, and multi- and single-robotic arms.

These technologies undergo radical embitterment when changing the viewpoint from Use Case 1 to Use Case 2. They are positioned in a middle area in Use Case 1, with relatively medium-low composite scores; however, they spring up to higher-than-average composite scores in Use Case 2, proving very resilient in their characteristic to operate in wide areas (operational range variable) and across all kinds of objects (debris size range variable). In other words, one could argue that when the intentions underlying the utilization of a specific technology are changed from Use Case 1 to Use Case 2, the most important feature is that capture-based technologies perform better, relative to other technologies. Therefore, the first recommendation implied by our analysis is the following:

Recommendation 1: Normative bodies should design, beyond general norms on the matter, a specific regulatory framework dedicated to ADR technologies that employ a physical capture method. This framework should be at least to some degree stricter than other, more general sets of norms.

As noted, this recommendation arises from the fact that capture-based ADR systems can raise greater concerns when directed at specific targets. While a full regulatory analysis is beyond the scope of this article, it is still possible to outline a few general options for shaping an appropriate framework. These could include clearer technical and operational standards, stronger transparency and notification practices for proximity operations, and the gradual inclusion of ADR-related guidance within existing space governance instruments. The aim is not to propose the creation of a new international authority but simply to highlight the types of regulatory measures that may become relevant if capture-based ADR technologies see dual-use application.

Moreover, a fully centralized institution with licensing powers would indeed be politically unrealistic under current international conditions, and our analysis does not claim this as a practical recommendation. Instead, our point is that existing voluntary, polycentric governance mechanisms could benefit from incorporating clearer authorization protocols and safety norms specifically tailored to ADR capture missions. Such measures would preserve the advantages of a decentralized system while ensuring that technologies with higher dual-use potential are subject to enhanced transparency and oversight.

A second consideration connects to the fact that all technologies appear heterogeneous in their risk assessment. Even if it is possible to group ADR systems by methods (capture-based systems, etc.), it is noteworthy that technologies included in the same group sometimes produce different results in our analysis. This means that possibly the best approach to the study of this matter is to consider ADR technologies as single-standing and avoid broad categorizations that may hinder differences between the systems. This is not to say that, for instance, a normative entity should create single sets of norms for each technology, but it also implies that the way to assure a correct management of risks may suggest a more granular approach than previously thought. Hence, a second recommendation is:

Recommendation 2: Actions regarding the development of ADR technologies may take a more focused, granular approach, avoiding the application of rules and best practices adopted for other similar technologies.

Here, the word actions is used to maintain a general tone. It may apply to regulation procedures as well as to private industrial investments, as well as to efforts by research institutions, etc.

There is a third consideration. The final scores shown in the graphs above may suggest a misleading conclusion, namely that there are in fact “safer” technologies in each use case. This is a wrong consideration for at least three reasons. First, the diversity reigning in the composite scores in the two use cases is a signal that, by changing the approach and the basic assumptions, the corresponding technology’s ranking might change radically. In other words, this way of thinking is not robust to a change of model. Second, this article presents a state-of-the-art analysis, hence all conclusions are based on the current state of technology. Note that elements impacting ADR technologies’ development can be very volatile in time; the most important instances are research streams, market opportunities, level of investments, country-level priorities in space, and defense programs. Therefore, it is of paramount importance to stress the necessity of periodic reevaluations and updates to this classification, given the dynamic nature of the space research landscape. Third, the results presented are very sensitive to the methodology employed and to the opinion of the evaluators. A methodological change could impact the technologies’ assessment and therefore imply different conclusions.

CONCLUSIONS

As space becomes increasingly congested, the risks associated with debris pose significant concerns for stakeholders, including policymakers, public actors, and private companies. The article has highlighted the dual-use nature of advanced technologies for ADR. As space becomes increasingly contested, this dual-use characteristic necessitates a thorough assessment of associated risks to ensure responsible utilization.

The primary goal of this work has been to systematically analyze the risks of several ADR technologies, potentially dual-use ones, through a weighted multicriteria model that includes both physical and dual-use factors. This provides insights into ADR solutions, and a framework for public recommendations is presented. Such kind of analysis is among the first ones in this field in terms of goals, structure, and methodology. The authors hope for a future, further expansion of the present work, in multiple interdisciplinary collaborative forms. Moreover, they hope that the public recommendations presented here will aid in the responsible implementation of these dual-use space technologies. Ultimately, the aim is to contribute to the ongoing discussions and decisions surrounding the safety, security, and sustainability of the space environment, addressing the needs of both the commercial sector and the public institutions.

AUTHORS’ CONTRIBUTIONS

C.L.M. and A.V.A.: Conceptualization, formal analysis, investigation, methodology, validation, visualization, writing—original draft, and writing—review and editing. M.R. and S.P.: Conceptualization, investigation, methodology, supervision, visualization, and writing—review and editing.

Footnotes

ACKNOWLEDGMENTS

The authors would like to thank Dr. Clelia Iacomino and Dr. Andrea Conconi for providing valuable consultancy on space policy matters during their time with the SEELab research group in the first version of this work, which was presented at the International Astronautical Congress 2023, held in Baku, Azerbaijan, from October 2–6, 2023. Copyright by IAF.

AUTHOR DISCLOSURE STATEMENT

The authors declare that there are no conflicts of interest related to this article.

FUNDING INFORMATION

This research received no external funding.

DATA AVAILABILITY

All data analyzed in this article are publicly available through the references cited.

ETHICS STATEMENT

This study did not involve human participants or animal subjects and therefore did not require ethical approval.

References

European Space Agency. ESA’s Annual Space Environment Report. European Space Agency; 2024.

Weeden

. Chinese ASAT Fact Sheet. 2010. Available from: https://www.thecipherbrief.com/files/74832/chinese_asat_fact_sheet_updated_2012.pdf

Carnegie Endowment for International Peace. India’s ASAT Test: An Incomplete Success. 2019. Available from: https://carnegieendowment.org/research/2019/04/indias-asat-test-an-incomplete-success?lang=en

International Institute for Strategic Studies. Russia conducts direct-ascent anti-satellite test. 2021. Available from: https://www.iiss.org/online-analysis/online-analysis/2021/11/russia-conducts-direct-ascent-anti-satellite-test/

Foust

. UN General Assembly Approves ASAT Test Ban Resolution. 2022. Available from: https://spacenews.com/united-nations-general-assembly-approves-asat-test-ban-resolution/

United Nations. Long-Term Sustainability of Outer Space Activities. 2023. Available from: https://www.unoosa.org/oosa/en/ourwork/topics/long-term-sustainability-of-outer-space-activities.html

Hakima

, Emami

. Assessment of active methods for removal of LEO debris. Acta Astronaut, 2018; 144:225–243; doi: 10.1016/j.actaastro.2017.12.036

Zhao

, Liu

, Wu

. Survey on research and development of on-orbit active debris removal methods. Sci China Technol Sci, 2020; 63(11):2188–2210; doi: 10.1007/s11431-020-1661-7

Kessler

, Johnson

, Liou

, et al. The Kessler syndrome: Implications for future operations. Adv Astronaut Sci, 2010:137.

10.

Rip

. Technology assessment. In: International Encyclopedia of the Social & Behavioral Sciences. Elsevier; 2015.

11.

Porter

, Rossini

, Carpenter

, et al. Guidebook for technology assessment and impact analysis. J Gen Philos Sci, 1984; 369–371.

12.

Dylander

. Technology assessment: As science and as a tool for policy. Acta Sociol, 1980; 23:217–237.

13.

Dobos

, Prazak

. To clear or to eliminate? Active debris removal systems as antisatellite weapons. Space Policy, 2019; 47:217–223; doi: 10.1016/j.spacepol.2019.01.007

14.

Emanuelli

, Federico

, Loughman

, et al. Conceptualizing an economically, legally, and politically viable active debris removal option. Acta Astronaut, 2014; 104(1):197–205; doi: 10.1016/j.actaastro.2014.07.035

15.

Froehlich

. A Fresh View on the Outer Space Treaty. Springer; 2018.

16.

Jakhu

, Pelton

, Nyampong

. Space Mining and Its Regulation. Springer; 2017.

17.

Migaud

. Protecting Earth’s orbital environment: Policy tools for combating space debris. Space Policy, 2020; 52:101361; doi: 10.1016/j.spacepol.2020.101361

18.

Alver

, Garza

, May

. An analysis of the potential misuse of active debris removal, on-orbit servicing, and rendezvous & proximity operations technologies. The George Washington University; 2019.

19.

Yalçın

, Martinez

, Delisle

, et al. ET-class: An energy transfer-based classification of space debris removal methods and missions. Front Space Technol, 2022; 3; doi: 10.3389/frspt.2022.792944

20.

Flores-Abad

, Ma

, Pham

, et al. Review of space robotics technologies for on-orbit servicing. Prog Aerosp Sci, 2014; 68:1–26; doi: 10.1016/j.paerosci.2014.03.002

21.

Kwok-Choon

, Romano

, Hudson

. Orbital hopping maneuvers with astrobee on-board the international space station. Acta Astronaut, 2023; 207:62–76; doi: 10.1016/j.actaastro.2023.02.034

22.

Virgili-Llop

, Zagaris

, Romano

, et al. A convex programming based guidance algorithm to capture a tumbling object on orbit using a spacecraft equipped with a robotic manipulator. Int J Robot Res, 2019; 38(1):40–72; doi: 10.1177/0278364918804660

23.

Shan

, Guo

, Gill

. Review and comparison of active space debris capturing and removal methods. Prog Aerosp Sci, 2016; 80:18–32; doi: 10.1016/j.paerosci.2015.11.001

24.

Yoshida

. Achievements in space robotics. IEEE Robot Automat Mag, 2009; 16(4):20–28; doi: 10.1109/MRA.2009.934818

25.

Raina

, Gora

, Maheshwari

, et al. Impact modeling and reactionless control for post-capturing and maneuvering of orbiting objects using a multi-arm space robot. Acta Astronaut, 2021; 182:21–36; doi: 10.1016/j.actaastro.2021.01.034

26.

Yoshida

, Kurazume

, Umetani

. Dual arm coordination in space. In: IEEE International Conference on Robotics and Automation 1991; IEEE; 1991; pp. 2516–2521.

27.

Blackerby

, Okamoto

, Iizuka

, et al. The ELSA-d End-of-Life debris removal mission: Preparing for launch. In: International Astronautical Congress. AIAA; 2019.

28.

Wilde

, Choon

, Walker

, et al. Using tentacle robots for capturing non-cooperative space debris. In: AIAA SPACE Forum. AIAA; 2017.

29.

Le Letty

, Meyer

, Scheper

. Clamping mechanism—A tentacles-based capture mechanism for active debris removal. In: International Astronautical Congress. AIAA; 2014.

30.

Botta

, Sharf

, Misra

, et al. On the simulation of tether-nets for space debris capture with vortex dynamics. Acta Astronaut, 2016; 123:91–102; doi: 10.1016/j.actaastro.2016.02.012

31.

Botta

, Sharf

, Misra

. Simulation of tether-nets for capture of space debris and small asteroids. Acta Astronaut, 2019; 155:448–461; doi: 10.1016/j.actaastro.2018.07.046

32.

Forshaw

, Aglietti

, Navarathinam

, et al. Remove debris: An in-orbit active debris removal demonstration mission. Acta Astronaut, 2016; 127:448–463; doi: 10.1016/j.actaastro.2016.06.018

33.

Campbell

, Hughes

, Vignjevic

, et al. Development of modelling design tool for harpoon for active space debris removal. Int J Impact Eng, 2022; 166:104236; doi: 10.1016/j.ijimpeng.2022.104236

34.

Sizov

, Aslanov

. Space debris removal with harpoon assistance: Choice of parameters and optimization. J Guid Control Dyn, 2021; 44(4):767–778; doi: 10.2514/1.G005484

35.

Huang

, Wang

, Zhang

, et al. Postcapture robust nonlinear control for tethered space robot with constraints on actuator and velocity of space theter. Intl J Robust & Nonlinear, 2017; 27(16):2824–2841; doi: 10.1002/rnc.3712

36.

Meng

, Huang

, Wang

. Attitude control of towed space debris using only tether. Acta Astronaut, 2017; 138; doi: 10.1016/j.actaastro.2017.05.012

37.

, Zhong

, Lu

. Optimal control scheme of space tethered system for space debris deorbit. Acta Astronaut, 2019; 165:355–364; doi: 10.1016/j.actaastro.2019.09.031

38.

Calabro

, Perrot

. Laser orbital debris removal and collision avoidance. Acta Astronaut, 2019; 158:220–230; doi: 10.1016/j.actaastro.2018.07.009

39.

Fang

, Pan

, Luo

, et al. Effects of deorbit evolution on space-based pulse laser irradiating debris. Acta Astronaut, 2019; 165:184–190; doi: 10.1016/j.actaastro.2019.09.010

40.

Bombardelli

, Pelaez

. Ion beam shepherd for asteroid deflection. J Guid Control Dyn, 2011; 34(4):1270–1272; doi: 10.2514/1.51640

41.

Urrutxua

, Bombardelli

, Hedo

. Preliminary design procedure for an ion-beam shepherd mission. Aerosp Sci Technol, 2019; 88:421–435; doi: 10.1016/j.ast.2019.03.038

42.

Cichocki

, Merino

, Ahedo

, et al. Electric propulsion subsystem optimization for ion beam shepherd missions. J Propulsion Power, 2017; 370–378; doi: 10.2514/1.B36105

43.

Toyoda

, Cho

, Masui

, et al. Preliminary investigation of space debris removal using electrostatic force. In: AIAA Aerospace Sciences Meeting. AIAA; 2009.

44.

Toyoda

, Reiso

, Cho

. Experimental investigation of space debris removal using electrostatic force. In: AIAA Aerospace Sciences Meeting. AIAA; 2012.

45.

Aslanov

, Yudintsev

. Motion control of space tug during debris removal by coulomb force. J Guid Control Dyn, 2018; doi: 10.2514/1.G003251

46.

Feng

, Li

, Zhang

. Geomagnetic energy approach to space debris deorbiting. Int J Aerosp Eng, 2019; 2019:1–18; doi: 10.1155/2019/5876861

47.

Feng

, Zhang

, et al. Theoretical and experimental investigation of geomagnetic energy effect for LEO Debris deorbiting. Aerospace, 2022; 9(9):511; doi: 10.3390/aerospace9090511

48.

Atashgah

MAA

, Gazerpour

, Lavaei

, et al. An active time-optimal control for space debris deorbiting via geomagnetic field. Celest Mech Dyn Astron, 2017; 343–360; doi: 10.1007/s10569-017-9755-y

49.

Mella

, Pergola

, Ruggiero

, et al. Foam-based method for active space debris removal. In: IAASS Conference. IAASS; 2012.

50.

Andrenucci

, Pergola

, Ruggiero

. Active removal of space debris: Expanding foam application. 2011. Available from: https://www.esa.int/gsp/ACT/doc/ARI/ARI%20Study%20Report/ACT-RPT-MAD-ARI-10-6411-Pisa-Active_Removal_of_Space_Debris-Foam.pdf

51.

Pergola

, Ruggiero

, Andrenucci

, et al. Low-thrust missions for expanding foam space debris removal. In: International Electric Propulsion Conference. IEPC; 2011.

52.

Parolin

, McAloone

, Pigosso

DCA

. How can technology assessment tools support sustainable innovation? A systematic literature review and synthesis. Technovation, 2024; 129:102881; doi: 10.1016/j.technovation.2023.102881