Clelia Iacomino, SDA Bocconi School of Management, Italy
Alessandro Rossi, National Research Council, Italy
Aristea Saputo, SDA Bocconi School of Management, Italy
Clelia Iacomino, SDA Bocconi School of Management, Italy
Alessandro Rossi, National Research Council, Italy
Aristea Saputo, SDA Bocconi School of Management, Italy
The stability of the space environment is a growing source of discussion among policy makers. This chapter first estimates the growth in the number of objects in low-earth orbit in the next decades under various mitigation scenarios, and then qualitatively assesses satellite operators’ economic incentives to adopt mitigation measures. The chapter concludes with a discussion of whether effective solutions to space debris challenges can emerge from a free-market setting or if public institutions need to intervene.
The increasing number of space objects in Earth’s low orbit poses a threat to the space environment’s long-term sustainability, increasing the risk of collision between active satellites and space debris. This problem is now on the agenda on international tables, especially since the latest episode regarding the Russian anti-satellite (ASAT) test in November 2021, when a Russian anti-satellite device destroyed a Russian satellite and created thousands of fragments, which are now travelling at high speed in Earth’s orbits and may cause future accidents (adding to the multitude of existing space debris). The Russian Federation and other countries such as the People’s Republic of China (hereafter “China”), India and the United States have conducted ASAT tests before, turning space objects into debris. Other potential sources of debris may be accidental collisions between active satellites (as proven by the first-ever unintentional impact, in 2009, which involved Iridium-33 and Cosmos-2251 and caused the dispersion of approximately 2 300 fragments), explosions or collisions, anomalous break-ups, and break-ups with unknown causes. To date, according to the European Space Agency’s estimates, in the Earth’s orbits there are around 36 500 debris greater than 10 cm, 1 million between 1 cm and 10 cm, and 330 million from 1 mm to 1 cm.
Number of launches since the start of the space age in 1957 |
About 5 253 |
Number of satellites placed in Earth’s orbit |
About 7 500 |
Number of satellites in Earth’s orbit |
About 4 300 |
Number of operational satellites |
About 1 200 |
Number of debris objects regularly tracked by the US Space Surveillance Network and maintained in its catalogue |
About 23 000 |
Estimated number of break-ups, explosions and collision events resulting in fragmentation |
More than 290 |
Total mass of all space objects in Earth’s orbit |
About 7 500 tonnes |
Number of debris objects estimated by statistical models to be in orbit |
29 000 objects >10 cm 750 000 objects from 1 cm to 10 cm 166 million objects from 1 mm to 1 cm |
Source: Data from the European Space Agency, cited in OECD (2019[1]), The Space Economy in Figures: How Space Contributes to the Global Economy, https://doi.org/10.1787/c5996201-en.
Moreover, over the last two years, the launch of mega-constellations in low-earth orbit (LEO) by private companies has significantly increased the space traffic in the LEO, potentially exacerbating future debris scenarios. Indeed, the number of active and defunct satellites in the LEO has grown by over 50%, to about 5 000. Communication satellite deployments in 2020 grew by 477% with respect to 2019’s record-high deployment of 175 communications satellites. Such an increase comes primarily from the deployment of 955 Starlink satellites from SpaceX and the deployment of 358 satellites from OneWeb. As regards earth observation, following a January 2021 launch of 48 SuperDoves, Planet now operates a global constellation of more than 437 active satellites.
Despite these threats, there is still no global binding regulation about satellites’ end-of-life to reduce the issue of space debris, as public institutions have provided mostly only voluntary guidelines about deorbiting activities. The United States, with the National Aeronautics and Space Administration’s Orbital Debris Mitigation Guidelines, originally introduced such voluntary norms in 1995 and with the US government’s Orbital Debris Mitigation Standard Practices in 2001 (updated in 2019). Similar mitigation guidelines were developed by the United Nations Office for Outer Space Affairs’ Committee on the Peaceful uses of Outer Space (UN COPUOS), with inputs from the Inter-Agency Space Debris Coordination Committee, and were adopted in 2007. Together with the 21 guidelines for the long-term sustainability of outer space activities, they form a set of measures that COPUOS member states and international organisations can voluntarily follow.
Despite the progress made by the international community in space debris mitigation over the last ten years (at the national and international levels) and despite the rapid increase in space debris, it is also becoming of primary importance for private companies (threatening future orbit operations and the terrestrial activities that rely on them, as well as space-related scientific research) to solve the technical and policy challenges hindering the potential solutions. The most important ones concern (Undseth, Jolly and Olivari, 2020[2]):
Compliance with the international guidelines and national provisions: Current compliance by public and commercial actors is insufficient, especially in the LEO. As reported in Figure 6.1, there has been a slight increase in compliance with such voluntary guidelines in recent years, both by active deorbit and natural decay, but the share of non-compliance is still high for all types of missions: defence, commercial and civil.
Third-party liability: While the development of active debris removal (ADR), meaning the removal of obsolete spacecraft or fragments through an external disposal method, is still under development, the unresolved legal questions of satellites’ ownership and liability pose several uncertainties as to whether a third party can remove the satellite owned by another country or company. Indeed, many countries consider interference with their space assets or capabilities as serious national threats and many of the technologies and techniques that are candidates for ADR operations could also be used to damage or destroy a spacecraft.
In recent times, there has also been a long international debate on mitigation measures regarding the feasibility of the so-called 25-year rule, which invites satellite operators to dispose of any satellite in the LEO to an orbit with at most 25 years of residual lifetime after the end of life. The discussion has arisen mainly with the increase of the mega-constellations in the LEO composed of short-lived satellites. Many actors in the space community criticised that the 25-year deadline is too long to allow dead satellites, which are ultimately dangerous space debris, to linger in orbit. They called for reducing the period in which satellites should be deorbited to as little as five to ten years, although there is little consensus about what that revised time frame should be. The major complaint with the hypothetical five-year rule is that it would incur additional costs for satellite operators (i.e. increased propellant costs). However, this rule may prove to be economically convenient if it demonstrates that in the long term it can help to avoid collision-related costs. It is worth stressing that the currently deployed mega-constellations (e.g. Starlink and OneWeb) are aiming at a much shorter residual lifetime with respect to the aforementioned 25-year rule, also thanks to their electric propulsion systems on board.
Earth’s natural ecosystems and orbits have several similarities. Most importantly for our analysis, both can be defined as common-pool resources, as anyone can access them, and the current overuse may hinder future generations’ possibility to enjoy them. Indeed, they are threatened by the irresponsible behaviour of individual operators who opt for personally beneficial strategies that do not correspond with the social optimum.
Orbits can be labelled as common-pool resources since it is difficult to prevent someone from occupying a place in an orbit, but overuse can reduce the benefits that all derive from it. Usually, those who benefit from common-pool resources have no incentive to preserve them, unless a shared organising principle imposes it. Indeed, as none of the users has a property right on the common-pool resource, and as the resource degradation occurs gradually as a response to its over-consumption, users are not stimulated to internalise the costs of their misconduct. This corresponds to the phenomenon of free-riding, meaning that some individuals do not contribute to the maintenance of the resource, waiting for others to do it and benefiting from their initiative. Currently, only a limited portion of the actors that benefit from orbits are taking care of their preservation, meaning that some players are adopting a free-rider strategy. Moreover, as risk related to satellite collisions, which is the main indicator of orbits’ degradation, is not yet perceived to be urgent and there are no laws requiring the management of space debris, orbit users do not have any incentive to take charge of expensive clean-up services.
Nonetheless, the number of space debris endangering orbits is projected to grow exponentially if no mitigation action is undertaken, the same way it is already happening to environmental stressors on Earth (e.g. carbon dioxide concentration, forest loss, ocean acidification) (Maury et al., 2019[4]). In the case of the Earth, the degradation of ecosystems has been attributed to the so-called “tyranny of small decisions”: “a situation in which a series of small, individually rational decisions, cumulatively results in a larger and significant outcome which is neither optimal nor desired and can negatively change the context of subsequent choices, even to the point where desired alternatives are irreversibly destroyed” (Kahn, 1966[5]). This dynamic now applies to the space debris issue as well. Even though this threatens future space activities, responses are still too piecemeal.
Given the many similarities, what differentiates terrestrial ecosystems and orbits is that while the cumulative impacts of pollutants that occur on Earth are derived from complex and still partially unknown ecological interactions (think about how little has been understood to date on how marine ecosystems interact with industrial activities pollutants), the probability of satellites colliding is at least partially predictable, as is the related generation of fragments, which result in an increased probability of further collisions. Such predictability leaves no room for interpretation concerning the relevance of the issue and it could help stakeholders to intervene in time to preserve the orbits’ integrity for current and future generations.
The question this analysis seeks to address is: can satellite operators within a free market solve the problem of space debris? Namely, is there an economic incentive for them to apply and finance mitigation technologies or binding regulations and is financial support needed from public institutions to overcome space debris challenges? To answer these questions, the Space Economy Evolution (SEE) Lab of SDA Bocconi School of Management, in collaboration with the Italian National Research Council (CNR), has explored the economic perspective of private satellite operators on the adoption of mitigation measures to reduce the risk of collision. Indeed, research-based evidence on private players’ economic incentive to act unilaterally may help to better understand mitigation practices and the potential of technology diffusion and, eventually, encourage private-public partnerships to accelerate the process and enhance compliance with international guidelines on space debris.
To answer this question, we divided the study into two parts: 1) the development of scenarios to assess the probability of a collision between active satellites and space debris, and the effectiveness of selected technologies in reducing the collision risk; and 2) an economic analysis based on a level of attractiveness model of the selected technology and a qualitative decision analysis.
In the first part, the CNR uses the SDM 5.0 (Rossi, Petit and McKnight, 2020[6]; Rossi et al., 2009[7]) evolutionary model to assess the collision probabilities and the effectiveness of mitigation measures. The first step of the analysis is to estimate the growth of the space objects in the LEO in the coming decades (up to 150 years from now). A more realistic reference scenario takes into consideration, on top of the traditional launch traffic, the presence of three mega-constellations and introduces post-mission disposal (PMD) according to the 25-year rule which fall into the category of relocation activities with a compliance rate similar to the one observed in recent years, collision avoidance for active spacecraft, refuelling and ADR measures, projecting their current level of adoption in the coming decades. The remaining scenarios test different increased adoption levels of mitigation and remediation measures to investigate their efficacy in reducing the number of foreseen collisions.
Then, starting from the results of the SDM 5.0 evolutionary model, we use a qualitative decision analysis model to evaluate the economic incentives of satellite operators to adopt selected mitigation measures (namely, those whose economic incentives are more ambiguous from a private satellite operator’s point of view). To develop this model, the first step was evaluating the attractiveness of the technologies of interest, looking at regulatory and technology risks, competition, and customer value to investigate how internal and external factors influence a company’s choice to adopt a technology. The selected technologies are the PMD and the ADR, which fall into the category of relocation activities.1 Table 6.A.7 The criteria adopted for the choice of these two technologies are based on their effectiveness to mitigate the risk of collision (if these technologies are used together) and the objective to understand if there is an economic convenience to adopt these technologies with a first qualitative analysis. PMD and ADR technologies can prevent further debris (deorbiting space objects) or reduce the number of pieces of debris (removing already existing debris) in space. More specifically, PMD solutions are used when satellites that have terminated their mission should be manoeuvred away from the LEO so as not to cause interference with other satellites. In this case, the satellite operator must choose whether to justify the cost of the fuel needed to deorbit its satellite within 25 years after the end of its useful life or to retain the same fuel for other mission objectives and simply accept the higher mission risks. ADR solutions involve the rendezvous and docking with, and ultimately removal of, an item of space debris. If satellite operators did not apply PMD solutions in the short term, there would be a need to develop a substantial number of ADR solutions in the medium and long term that are more expensive than post-mission solutions.
Second, we develop the qualitative decision model, which focuses more specifically on the economic incentive, taking into consideration the:
1. different scenarios characterised by varying collision risks, based on the actions of other companies (which determine the overall adoption level of mitigation measures and, as shown by the SDM, the corresponding number of collisions and space debris)
2. costs incurred by a single satellites operator for each potential choice (i.e. adoption or non‑adoption) of mitigation measures.
The qualitative model is the first stage of a future quantitative analysis that will calculate the expected values of the outcomes of alternative choices and outline the optimal decision (i.e. adoption or non‑adoption) for satellite operators.
Our analysis focused on the LEO (where the number of objects is rapidly increasing and where most collisions are expected), considering space objects bigger than 5 cm and looking ahead to 150 years from now. The CNR used the SDM 5.0 Evolutionary Model to assess collision probabilities and the effectiveness of mitigation measures in reducing them. The SDM estimated the growth of the space objects, as determined by future launches from Earth and by in-orbit collisions (Rossi et al., 2009[7]; Rossi, Petit and McKnight, 2020[6]). To explore the future potential collision risk (i.e. probability), the CNR developed different scenarios representing the possible evolutions of the space debris population as determined by different levels of adoption of selected mitigation technologies: collision avoidance, PMD and ADR.
Among these, we decided to focus on PMD and ADR, as the economic incentives for adopting them are ambiguous. In the case of PMD, satellites operators need to devote part of their satellites’ fuel to deorbiting manoeuvres, potentially renouncing some mission objective; in the case of ADR, the technology development or purchase still implies high investments. Moreover, in both cases, the adoption of these measures by a single operator does not imply a reduction of the overall collision probability. On the other hand, refuelling and collision avoidance adoption provide an intuitive economic return, as refuelling allows extending satellites’ useful life, and collision avoidance helps to avoid a collision when it is going to occur.
For the current work, five different scenarios were considered: a reference scenario (REF), against which to compare all the others, represents a “business-as-usual” projection, while the remaining four mitigated scenarios (C1, C2, C1_ADR, C2_ADR) simulate additional mitigation and remediation measures.
REF encompasses a standard launch traffic derived from past activities (i.e. not including mega‑constellations) and currently observable levels of compliance with mitigation measures. On top of this, as SDM allows for the inclusion in the launch traffic of large constellations with their own specific traffic and maintenance procedures, three large constellation launches are simulated. The three constellations are respectively similar to the Starlink, Oneweb and Kuiper constellations, featured with a 150-year lifetime and adding 1 594, 720 and 1 156 satellites to the standard satellites (non-constellation) population.
In REF, the 25-year rule is supposed to be applied only to 50% of the satellites (in the following, we refer to this behaviour as “50% compliance to the 25-year rule”). All the active satellites not belonging to a constellation perform collision avoidance with an efficiency of 60%; while those that are part of a constellation perform it with a 95% efficiency against objects not belonging to the constellation itself (no impacts between operational satellites of a given constellation are allowed). It is important to highlight that only objects larger than 10 cm can be avoided. Indeed, no objects between 5 cm and 10 cm can be avoided because of the assumed limits in space surveillance systems. Refuelling is performed for two standard (non-constellation) satellites larger than 500 kg per year (starting from the year 2030), implying that two less satellites are launched.
In C1, all the measures described for REF apply, with the following differences: the 25-year rule is applied with a compliance rate of 80% (compared to 50% in REF) and the efficiency for the collision avoidance of standard satellites is 70% (compared to 60% in REF). In C2, the only differences from REF are that the residual lifetime in the PMD is changed from 25 years to 5 years, and the compliance to this 5-year rule is assumed to be 60%. This allows investigating whether it is better to “impose” fast deorbit, with the risk that many operators will not follow the rule (due to increased costs in propellant) or if it is better to deorbit over a longer timeframe (less propellant required), but with higher compliance. Finally, 70% efficiency for the collision avoidance of standard satellites is simulated (compared to 60% of the REF case). In C1_ADR, the same setting as scenario C1 applies, with the addition of four ADR per year, starting in the year 2028 (i.e. every year the four abandoned objects with the highest product – mass x collision probability – are removed from the simulation). In C2_ADR, the same setting as Scenario C2 applies, with the addition of four ADR per year, starting in the year 2028.
Figure 6.2 shows the number of objects larger than 5 cm (panel A) and the overall number of collisions against objects larger than 5 cm (panel B) in the REF, C1 and C2 scenarios. To start, it is worth saying that active satellites represent about 0.5-0.6% of the total population of objects at the final epochs of the simulations. Abandoned spacecraft and fragments compose the vast majority of the population.
When comparing REF with C1, increasing the compliance with the 25-year rule from 50% to 80% (along with a slightly better collision avoidance) reduces the number of objects larger than 5 cm by 25% and the total number of collisions by about 26%. This, once again, highlights the importance of full compliance with the currently adopted mitigation measures.
Further on, comparing C1 and C2, a stricter mitigation measure (a 5-year rule as opposed to the 25-year rule) but with a lower compliance rate (60% as opposed to 80%) leads to an increase of about 11% in the number of objects and about 5% in the total number of collisions. Indeed, although initially the C2 scenario appears comparable or even slightly better than the C1 scenario thanks to the reduced residual lifetime, in the longer run, the accumulation of objects abandoned in space (due to reduced compliance) starts to damage the environment and generate additional collisions.
In mitigated scenarios C1_ADR and C2_ADR (Figure 6.3), each year four objects are removed through ADR. As expected, the ADR significantly improves the situation, leading to a ~10% reduction in the final number of objects larger than 5 cm in both the C1_ADR and C2_ADR scenarios and a ~11% reduction in the overall number of collisions for the C1_ADR case and of ~15% for the C2_ADR case. Note that in panel B, the final number of collisions is nearly equal in the C1_ADR and C2_ADR scenarios. Nonetheless, it is worth stressing that the growth pace of the C2_ADR is significantly steeper than for the C1_ADR case due, as already mentioned, to the accumulation of inactive spacecraft (i.e. collisional cross‑section) in the case where only 60% of the spacecraft are disposed at the end-of-life (even if with a lower residual lifetime).
Considering the results of the CNR’s analysis and the mitigation effects of the PMD and ADR combinations, the SEE Lab evaluates the level of attractiveness of these technical solutions considering business and international risks.
The attractiveness model analyses the context in which a firm operates to evaluate how external and internal factors (environmental and industrial aspects respectively) influence a company’s adoption of a technology. The higher level of attractiveness indicates the most valuable business segment to invest in.
Environmental aspects include two factors: 1) the regulatory risk, which describes the possible occurrence of adverse interpretation of the legislative framework and contracts governing the operations of service companies; and 2) the technology risk that arises in projects based on technologies that have not been fully consolidated in the past. In parallel, the analysis of industrial factors considers how the technology of interest could help respond to customer demand and the intensity of competition, referred to as the supply-side structure of the market. The result of this analysis provides a comprehensive evaluation of the technology’s level of attractiveness (Figure 6.4).
What emerged from the analysis (see Annex 6.A) is that PMD has the highest level of attractiveness and the lowest level of risk and barriers to entry in terms of technology feasibility, technology maturity and value proposition. As regards ADR, there are high risks in particular related to the regulatory framework, which limits market development. For example, the liability issues need to be clarified on the following aspects:
Identification of the proportion of debris for which each country is responsible.
Development of protocols/agreements between launching country and third-party removal entities.
Defining who is responsible if a third party is damaged during the removal process.
Security issues related to military satellites induce some countries like China, the Russian Federation and the United States to be reluctant to allow other governments and private companies to interfere with their satellites, and this could be a limitation for developing this market.
Many countries view interference with their space assets or capabilities as serious national threats. Many of these threats come in the form of ASAT capabilities, which can be used to deceive, deny, degrade, disrupt or destroy space capabilities. Although ADR operations are not inherently ASAT activities, they may cause instability and mistrust, as many of the technologies and techniques that are candidates for ADR operations could also be used to damage or destroy a spacecraft.
Given the key role envisaged for PMD and ADR, it is worth asking whether private space operators have the economic incentive to enact such measures to tackle space debris. Our decision analysis investigated if reducing the collision risk provided by PMD and ADR and the consequent decrease of the collision-related economic losses can drive satellite operators to adopt these practices (Figure 6.5).
The analysis took into consideration three main factors that may influence satellite operators’ decision to adopt (or not) mitigation measures:
collision probability, assuming that a higher probability of collision may be an incentive to deploy mitigation practices
costs derived from collisions, meaning the cost of substituting hit satellites, if they cannot be repaired, or the cost of repairing services, if collision-related damages can be fixed, as well as the costs derived from the interruption of the hit satellites’ functionalities
costs of adopting mitigation measures, which, with regards to PMD, could be mainly represented by fuel costs for disposal manoeuvres, while in the case of ADR it could correspond either to the cost of internally developing the ADR technology or to that of a third-party provided ADR service.
Our model started by considering these three elements, as they are very basic factors that impact on each space operator’s choice to adopt mitigation measures or not.
Nonetheless, another aspect needs to be taken into account. As in the case, for example, of greenhouse gas emissions, when a large number of actors exerts negative pressure on a common-pool resource, individual mitigation initiatives do not necessarily correspond to a timely decrease in the overall environmental risk. Consider a company that opts for limiting its carbon dioxide releases: although this choice could have an impact, air quality would still be affected by other firms’ emissions. The same holds true for space debris. This means that other players’ decisions could bias a single operator’s choice. For this reason, our decision analysis investigated a single player’s opportunities (i.e. bearing or not costs related to PDM and/or ADR) in relation to three scenarios:
low overall adoption of mitigation measures (i.e. only 50% of objects are removed from the orbit), corresponding to a high probability of collision and high collision-related costs
medium overall adoption of mitigation measures (i.e. 80% of objects are removed from the orbit), corresponding to an intermediate probability of collision and intermediate collision-related costs
full overall adoption of mitigation measures (i.e. 100% of objects are removed from the orbit), corresponding to a low probability of collision and low collision-related costs.
Assuming a private operator’s perspective, PMD and/or ADR adoption is worthwhile when the cost of their deployment is lower than the potential losses derived from collision events. However, this fundamental dynamic based on a comparison between the cost of the mitigation measures and the cost of collisions depends on satellites’ actual exposure to damages, meaning the risk of collision and what influences it. As anticipated above, other players’ behaviour assumes here a crucial relevance, as the overall rate of adoption of mitigation measures determines the number of space objects left in the orbit as debris that may cause an accident. Consequently, as highlighted in our model, if a satellite operator decides to enact mitigation measures in parallel with a low overall rate of adoption, its initiative may result in a very limited impact on the risk of collision. Such a dynamic could discourage unilateral initiatives. Conversely, collective actions would be more effective and encourage single players to proceed. Importantly, in the latter case, guarantees against freeriding should be provided. Indeed, a high rate of deployment of mitigation measures may tempt some operators to benefit from the majority’s mobilisation while continuing their misconduct. Even if the presence of an economic incentive to enact mitigation measures leads a large portion of players to make the same choice without co-ordinating, it is probable that a wide adoption would be achieved gradually, leaving space for freeriding. Thus, our model shows how both mitigation measures costs and collision probability and costs, as determined by the overall rate of adoption of mitigation measures, are key factors in a single operator’s choice. How could public institutions intervene to support this fragile free‑market framework?
At first, public actors’ intervention may lower the costs of adopting mitigation measures through the deployment of co-financing measures (e.g. public-private partnerships model). For example, current estimates about ADR costs make it hard to believe that private parties could develop and operate ADR technologies without any external support. In this case, public bodies may help either by contributing to the creation of a market for space debris disposal, in which new companies may provide an ADR service to private and public space operators, or by providing direct financial support to ADR technology development. Second, as broad adoption of mitigation measures is crucial to effectively reduce the amount of space debris, binding guidelines issued by public institutions may boost the overall rate of deployment of mitigation practices as well as prevent the risk of freeriding.
Our analysis showed that the two most effective bundles of mitigation measures include different practices whose deployment requires the collaboration of private parties with public institutions. As in the case of climate action, orbits’ stakeholders are beginning to mobilise. During the last Paris Peace Forum, held in November 2021, ten companies and organisations from the space sector gave birth to the Net Zero Space, a multi-stakeholder initiative including different players, from satellite operators to launchers, from space agencies to universities and civil society, all committed to develop and deploy concrete measures to reduce the amount of space debris by 2030. As claimed by some of the signatories, partnerships with governments and public institutions will be key to achieving the long-term sustainability of outer space activities.
The SDA Bocconi SEE Lab is continuing its studies on the space debris issue, furthering its effort to find the best solution for all the stakeholders involved. In particular, the next steps will consist of shifting the discussed model from a qualitative to a quantitative approach and, through a cost-effectiveness perspective, helping companies outline the best route concerning collision risk stewardship.
[3] ESA (2022), ESA’s Annual Space Environment Report 2022, European Space Agency, https://www.esa.int/Safety_Security/Space_Debris/ESA_s_Space_Environment_Report_2022.
[5] Kahn, A. (1966), “The tyranny of small decisions: Market failures, imperfections, and the limits of economics”, Kyklos, Vol. 19/1, pp. 23-47, https://doi.org/10.1111/j.1467-6435.1966.tb02491.x.
[4] Maury, T. et al. (2019), “Assessing the impact of space debris on orbital resource in life cycle assessment: A proposed method and case study”, Science of the Total Environment, Vol. 667, pp. 780-791, https://doi.org/10.1016/j.scitotenv.2019.02.438.
[1] OECD (2019), The Space Economy in Figures: How Space Contributes to the Global Economy, OECD Publishing, Paris, https://doi.org/10.1787/c5996201-en.
[7] Rossi, A. et al. (2009), “The new space debris mitigation (SDM 4.0) long term evolution code”, in Proceedings of the 5th European Conference on Space Debris, https://conference.sdo.esoc.esa.int/proceedings/sdc5/paper/48 (accessed on 17 January 2022).
[6] Rossi, A., A. Petit and D. McKnight (2020), “Short-term space safety analysis of LEO constellations and clusters”, Acta Astronautica, Vol. 175, pp. 476-483, https://doi.org/10.1016/j.actaastro.2020.06.016.
[2] Undseth, M., C. Jolly and M. Olivari (2020), “Space sustainability: The economics of space debris in perspective”, OECD Science, Technology and Industry Policy Papers, No. 87, OECD Publishing, Paris, https://doi.org/10.1787/a339de43-en.
Components |
Key features |
Level of threat |
Threat score |
||
---|---|---|---|---|---|
Low |
Medium |
High |
|||
Technology maturity |
Active deorbit strategies basically need continuous power supply together with attitude and orbit control subsystems (AOCS) to achieve the deorbit. Among the active methods are on-board propulsion, electric propulsion and solid propulsion (e.g. smart propulsive device currently at qualification level). Deorbiting is particularly challenging for micro and nanosatellites, as they are limited in terms of mass and volume. Consequently, there is no mature deorbiting technology targeted toward this class of satellite. Passive technologies: There are only a few high devices with a technology readiness level equal to 7 guaranteed to satisfy the 25-year requirement as most small spacecraft are unable to relocate to a graveyard orbit due to propulsion limitations. NanoSail-D2, CanX-7, TechEdSat-3, TechEdSat-4 and TechEdSAt-5 are all CubeSat platforms that have successfully demonstrated the use of drag sails for deorbiting in low-earth orbit within the 25-year post-mission requirement. |
√ |
Medium |
||
Feasibility |
Technical feasibility: Active technologies reached a higher level of maturity whereas the development of passive devices has been revitalised over the last decades, mostly driven by the space debris problem. The absence of mature devices and the existence of a long flight history for some of them make it difficult to identify the deorbit technology that will dominate the market in the coming decades. However, a comparison of different studies shows that bare electrodynamic tethers (BETs) may dominate other technology in terms of performance and reliability. The word fair is used here to highlight the importance of recent BET progress. |
√ |
|||
Threats |
Private spacecraft operators may not be motivated to carry out end-of-life disposal, because they have to sacrifice economic interests in proportion to the fuel consumption for deorbiting or re-orbiting. Additionally, small satellites that are making inroads into every area of space applications and will change the orbital environment as we know it substantially, may not have a propulsion system to perform such a manoeuvre. |
√ |
Components |
Key features |
Level of threat |
Threat score |
||
---|---|---|---|---|---|
Low |
Medium |
High |
|||
Market target |
Low-earth orbit, commercial satellites (in particular satellite constellations). |
√ |
Medium |
||
Potential opportunity |
Potential customers Active technologies: Electric propulsion (EP): given the size limit of small satellites combined with this multimanoeuvre requirement. In particular, cubesats have a strictly limited volume and mass, an obstacle when it comes to propellant storage. |
√ |
|||
Value proposition |
Passive disposal strategies that take advantage of aerodynamic drag as the deorbit force are particularly attractive because they are independent of spacecraft propulsion capabilities. Active deorbit technologies Satellite operators sacrifice propellant, and therefore the satellite’s life and potential revenues, to perform collision-avoidance manoeuvres. Direct costs such as propellant consumption for collision avoidance manoeuvres, downtime during manoeuvres and end-of-life decommissioning have a big impact on the cost of orbital slot occupation and insurance premiums. This strategy can strongly limit operational lifetime, as fuel mass is dedicated to the deorbiting (up to 20% of the spacecraft mass. For this reason, it could be interesting to adopt EP systems, with the aim to cut down on propellant mass. |
√ |
Components |
Key features |
Level of threat |
Threat score |
||
---|---|---|---|---|---|
Low |
Medium |
High |
|||
Active technologies Trend: electric propulsion for small satellites or cubesat (active technologies) |
Satellites companies with electric propulsion: SpaceX, Astro Digital, Kinèis, ExoTerra Resources LLLC Production of electric propulsion:
|
√ |
High |
||
Passive technologies Trend: solar sails, deployables, electromagnetic tethers |
Production of passive technologies
|
√ |
Components |
Key features |
Level of threat |
Threat score |
||
---|---|---|---|---|---|
Low |
Medium |
High |
|||
Obligation |
The lack of an obligation of countries to deorbit their objects at the end of lifetime. |
√ |
High |
||
Criteria |
The difficulty in defining criteria on deciding which objects should be removed or manoeuvred if they pose a risk for other space objects. |
√ |
|||
Space traffic management |
The challenges for establishing a space traffic management system. |
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Debris mitigation and avoidance regulations are steadily becoming more restrictive. So far, all of the most exploited regions of orbital space are protected by regulations. Best practices formulated by the Inter‑Agency Space Debris Coordination Committee are being implemented at the national level in new licensing, in satellite manufacturing and in insurance contracts. In some cases, national legislation implements additional regulations for debris prevention.
The French Space Operation Act requires all national and international operators active on French territory to decommission all LEO satellites orbiting within 2 000 km at the end of their operational lives. This will involve making the satellite re-enter the atmosphere in a controlled way independently from the casualty risk criteria that is highlighted in several other international standards.
A specific field falling in the on-orbit servicing domain is active debris removal (ADR), which includes a variety of technical solutions and approaches to deorbit target objectives in space.
Traditionally, space sustainability has been approached as a government-to-government issue, but several emerging private companies, entrepreneurs and commercial space ventures are racing to take part in this market.
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Technology maturity |
Active debris removal (ADR) is not a straightforward operation, especially in cases where the targeted satellites to be removed are to some extent uncooperative. |
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High |
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Feasibility |
Economic feasibility There need to be industries involved in this new market, and interests might be given through the definition of a valuable business model that could provide commercial benefits. In addition, the feasibility of ADR should be based on the following concepts:
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Threats |
There are unresolved questions as regards liability from ADR operations: if the launching country is removing the space object, and in the process of disturbing the object it fragments, is the launching country liable for any damage those fragments cause to other space objects in the future? No standard of care exists for ADR operations, and thus it may be impossible to currently establish whether or not the removal operations were carried out in a negligent manner. If the ADR is being performed by a third party, this creates additional complexities if the removal spacecraft incurs damages in the process of the removal, or if they damage other spacecraft as a result of the removal operations. |
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Market target |
Environmental critical debris: rocket upper stages and defunct satellites that are already in orbit. |
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High |
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Potential opportunity |
Potential customers
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Value proposition |
The revenue model given by the active debris removal (ADR) technologies are not based on a classical business model that delivers profits to customers, but through a probability of saving the current profits. Indeed, the value of ADR is mainly preserving the long-term space activities, not necessarily on giving direct profits to the ADR manufacturers. |
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The ADR activities do not provide this added value in terms of commercial business, neither for satellite manufacturers nor for the launcher operators. It is therefore difficult to identify the relationship between debris removal and individual commercial interests. There are three types of potential customers for debris removal services: satellite operators, insurers and national agencies. The market for ADR services includes all these potential customers and each of them has different needs for debris removal services, meaning that a tailored value proposition is required. The general business model of a debris removal service is not based on a business model that delivers profits to customers, but through a probability of saving the current profits.
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Opportunities created by public programmes |
Business opportunity seekers: companies leveraging opportunities created by public programmes in the field of space debris removal. AIRBUS (CleanSat and eDeorbit), Start Technology and Research (ElectroDynamic Debris Eliminator [Technology Readiness Level, TRL] 5-6) vehicle. |
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Medium |
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Solutions developed independently from public institutions |
Autonomous space debris removal-related businesses: companies whose business model is based on solutions developed independently from public institutions and addressing mainly commercial markets: Astroscale, ClearSpace, Share my Space, Orbit Fab, Georing. |
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Commercial solutions integrated into public programmes |
Support service providers: companies offering commercial solutions that can support other private endeavours or be integrated into public programmes related to the removal of space debris. Seer Tracking, LeoLabs, D-Orbit, Altius Space Machine, Scout Aerospace, Obruta Space Solutions. |
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The ADR business line is focused on removing existing orbital debris, none of which have been prepared with a docking plate and thus are more difficult to capture.
Most of these existing debris are the result of institutional missions and thus will be a market driven by governments and space agencies.
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Treaties |
These treaties did not mention who must remove debris or their fragments and the space law did not mention any obligation to do so. The Liability Convention and the Outer Space Treaty consider the debris and the fragments as individual projects and in the case of an active debris removal (ADR) process, these two treaties do not identify who is responsible if a third party removes a piece of debris by mistake or causes trouble to a piece of debris which can damage another satellite. |
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High |
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Satellites with military and security purposes |
Some satellites have been launched for military and security purposes. For political reasons, some countries like the People’s Republic of China, the Russian Federation and the United States are reluctant to allow other governments to interfere with their satellites or fragments, for these reasons the dual-use nature of ADR technologies imply strategic and military implications in the framework of policy considerations. |
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Owner-operators |
ADR spacecraft that conduct repeated or continual manoeuvres to collect multiple pieces of debris may require special traffic management procedures. Their owner-operators will likely be required to continually publish updates of the spacecraft’s position. |
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Dual-use nature of ADR |
The dual-use nature of ADR operations can cause instability and mistrust. Thus, many countries view interference with their space assets or capabilities as serious national threats. Many of these threats come in the form of anti-satellite (ASAT) capabilities, which can be used to deceive, deny, degrade, disrupt or destroy space capabilities. Although ADR operations are not inherently ASAT activities, many of the technologies and techniques that are candidates for ADR operations could also be used to damage or destroy a spacecraft. |
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All the laws and regulations regarding space policy should be reviewed. Space law includes five major treaties; two of them address ADR issues: 1) the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space – the Outer Space Treaty of 1967; and 2) the Convention on International Liability for Damage Caused by Space Objects of 1973 (the Liability Convention), defining the liable party as the “launching state”.
Different space agencies (such as the European Space Agency, the Italian Space Agency, the National Centre for Space Studies in France and the German Aerospace Center) are showing the shared awareness about space debris problem. The issue is these efforts are non-binding guidelines, without addressing any legal or political measures that would oblige the space industries to comply with them.
← 1. Relocation activities regard the modification of a satellite’s orbit with the aim to boost the satellite to higher or lower orbits for end-of-life retirement, to perform a controlled re-entry of LEO satellites, or to rescue satellites stranded from a manoeuvre or due to launch vehicle failure.