As companies move ahead with plans for megaconstellations of satellites in low Earth orbit, dealing with the orbital debris problem becomes a pressing technical and legal issue. (credit: OneWeb)
The urgency of active debris removal (ADR) of orbital debris is fueled by the dramatic increase expected in trackable and untrackable objects in orbits around the Earth within the next decade. There are about 1,500 functioning satellites in Earth orbit, sharing space with about 6,300 metric tons of orbital debris. About 800 of these working satellites are in low Earth orbit (LEO). Some of the altitude and inclination bands in LEO are becomingly perilously crowded with both functioning satellites and orbital debris. Most satellites currently in LEO are government owned and operated. However, private companies are planning to launch over 20,000 new commercial satellites, mostly into LEO, though several thousand are headed to medium Earth orbit (MEO).1
SpaceX alone (likely under the trademark name Starlink) plans in 2019 to begin launching a constellation of 4,425 low-latency high-capacity broadband satellites at around 1,200 kilometers altitude and proposes to eventually launch another 7,500 satellites at much lower altitudes.2 OneWeb intends to launch 720 such satellites at around 1,200 kilometers and another 1,280 satellites in MEO. Boeing plans to launch 2,956 satellites into LEO, Samsung 4,600 satellites, Telesat 290 satellites, and Theia Holdings 112 satellites. There are other companies with such plans as well.3
SpaceX, OneWeb, and Samsung together are planning for their mega-constellations of satellites to be around an altitude 1,200–1,400 kilometers, albeit at different inclinations. Just one of these LEO mega-constellations is expected to incur 2,000 to 3,000 conjunction warnings per day, with two to three within 50 meters.4 If there is just one collision among these satellites or their corresponding upper stages, the number of events to actively deconflict drastically climbs, and a runaway chain reaction of collisions could be produced. If such a catastrophic “Kessler Syndrome” were to occur in other crowded orbits as well, global communications, navigation, weather, and other satellite services could eventually become disabled.5
MEO, which currently contains only 96 satellites,6 is relatively free of debris.7 However, OneWeb wants to place another 1,280 satellites in MEO at a (so far) publicly undeclared altitude.8 Viasat and O3b also plan to launch satellites into MEO at an altitude of 8,200 kilometers.9 Because our Global Positioning Satellites orbit in MEO at an altitude of 20,200 kilometers, there is currently little danger of collisions from the newly planned commercial satellites or their upper stages. However, markets and industries rely on GPS satellites to provide not only navigation services, but also precise timing information for financial transactions. For these reasons, a watchful eye must be kept on new satellites to be launched into this orbit.10 Traffic in geostationary Earth orbit (GEO) is also becoming congested with working and non-working satellites, but radio interference considerations and the finite number of available orbital slots limits growth in the number of new satellites.11
While not all these constellations may be fully implemented, we are, nevertheless poised for a dramatic growth in the usage of space for a variety of beneficial purposes, mainly broadband data communications and Earth observation.
Orbital debris threatens our modern way of life and future space plans
Against this backdrop of exponential increase in the number of satellites and their upper stages in LEO and MEO lies the threat of orbital debris from previous launches, consisting of whole and pieces of defunct upper stages and satellites. Several orbital bands in LEO between 600 and 1,020 kilometers are already dangerously crowded with both working satellites and orbital debris (see Figure 1 below). The altitudes from 460 to 660 kilometers, while not yet so crowded, are still incurring a growth in orbiting objects. Note also that Figure 1 only indicates the mass and number of tracked objects.12 A much larger number of debris objects are not tracked because they are too small to be spotted by heritage tracking systems, which typically only track objects larger than 10 centimeters in diameter.
For example, there are approximately 700,000 untracked debris objects ranging in size from 1 to 10 centimeters in orbit. These objects are dangerous to spacecraft and people, but currently there does not exist a practical way to shield against them. With relative impact velocities in LEO approaching 56,000 kilometers per hour, shrapnel as small as one centimeter (the size of a playing marble) can completely disable a multi-ton satellite, damage the ISS, or kill humans carrying out spacewalks. A 100-gram bolt striking a space station module would certainly be a lethal event.13
Because these smaller objects are produced when larger spacecraft or debris break up or suffer collisions, the LEO altitudes in Figure 1 that show the highest mass represent the altitudes that will produce the greatest amount of future debris. Without active intervention, these masses will produce more orbital shrapnel even if we never launch another spacecraft. However, as mentioned above, many more satellites with their attendant upper stages, are about to be launched.
Figure 1. Number of tracked objects in LEO (larger than 10 cm in diameter) and their total mass as a function of altitude. (credit: Darren McKnight and Patrick Dingman (2012))
Effective ADR should be a part of a comprehensive, international system of space traffic management (STM) dedicated to maintaining the space environment safe for humans and spacecraft.14 Another part of that comprehensive STM system would be a greatly enhanced space situational awareness (SSA) that can track dangerous debris smaller than ten centimeters in diameter and which can give frequent, accurate, and real-time conjunction warnings. Still another part would be worldwide, enhanced and relentless orbital debris mitigation,15 which should include:
- designing satellites and space systems to minimize debris the release in normal operations,
- developing methods to reduce the risk of fragmentation or explosion at end-of-life by venting leftover fuel or discharging batteries, and
- properly disposing of spacecraft and spent rocket stages as soon as they are no longer useful.16
To sum up, without a worldwide, coordinated crash program of comprehensive STM (including enhanced SSA, orbital debris mitigation, and ADR), the more than 20,000 new satellites proposed for launch will make the current orbital debris and satellite situation much more dangerous and complicated.
Space lessons from thousands of years of maritime tradition?
In developing provisions to manage space debris, it is important to note that Earth orbits are present an environmental situation more akin to the maritime environment than the aviation environment.17 Among other things:
- When aircraft create debris consequent to catastrophic failure over land, it is usually confined to one identifiable terrestrial area. Conversely, ocean vessels sometimes suffer loss of control, are shipwrecked, or contaminate large swaths of the maritime environment with mobile debris: solid objects, such as abandoned vessels, flotsam and jetsam; or liquids, such as oil. These consequences of catastrophic failure and normal operations also result in the outer space environment.
- Space tourism will turn out to be more like cruise ship tourism, where destinations may be part of the package, but at least part of the fun will be enjoying the cruise itself, usually with others. With aviation, you simply want to get to another destination as soon as possible, except on very rare occasions, travel on the aircraft itself is not a tourist attraction.
- Aviation can offer no unique destinations, i.e. destinations that cannot already be reached by land or sea. Space transportation, however, can take us to points in space that have never been reached before.
- Space activities sometimes resemble specialized maritime activities such as the offshore oil industry, where the destination is an emplaced artificial structure (the ISS, for example) in the medium and serviced by spacecraft, like ships servicing offshore oil rigs within an ocean medium.
- Space travel often resembles maritime transportation more than aviation transportation because it is conducted in “voyage mode” rather than “sortie mode.” That is, aircraft operations carrying people take place within hours, whereas space operations carrying people will likely more often take weeks or months.
- The commercial space-launch industry resembles the maritime sector much more than the air-transport sector in that a large part of the business is exposed to international competition. The US aviation industry, however, enjoys a very large protected domestic market, and is further protected by international aviation agreements.
The first item in the comparison of maritime and space characteristics above states that ocean vessels sometimes suffer loss of control, are shipwrecked, or contaminate the large swaths of the marine environment with mobile solids or liquids. To deal with such human-produced sea perils, maritime history has a long history of commercial “salvors” who are rewarded for rescuing ships and their cargo, clearing shipwrecks from shipping lanes, and eliminating or preventing other environmental hazards.
Historically, salvors were rewarded only if they met three conditions: the vessel or cargo must be in peril; the salvor must be acting voluntarily and under no contract existing before the peril; and the salvor must be successful in his efforts (“no cure, no pay”), although payment for partial success was traditionally granted under certain circumstances. Also, salvage tradition until 1980 only recognized a ship, cargo on board, freight payable, and fuel (“bunkers”) carried on board as subject to salvage, if in “peril,” defined broadly.
The concept of salvage was extended by Lloyds Open Form 1980 (LOF 80), a standard salvage agreement form approved by the Committee of Lloyds.18 This form provided that a salvor might be paid, even if there was no “cure” or salvage of property, if the salvor’s services prevented the environmental contamination of an oil spill. Thus, the ship owners under a LOF 80 contract had to reimburse a salvor for his expenses, plus a supplement up to an additional 15 percent in the case where the salvor also prevented an oil spill. This supplement was referred to as the “safety net,” and its introduction reflected a growing worldwide awareness of the danger of oil contamination in the sea environment.
However, the LOF 80 was only a stopgap measure. The concept of special compensation beyond pure property salvage for preventing environmental damage was codified and expanded by the International Convention on Salvage, 1989 (Convention),19 which entered into force on July 14, 1996. Article 14 of the Convention considers protection of the environment (even beyond oils spills) as part of salvage and therefore subject to reward if contamination is prevented by the salvor. Such reward, informally called “liability salvage,” is termed “special compensation” by the Convention, as opposed to compensation for property salvage.
Under the Convention the main salvage award is still based on “no cure no pay.” Nevertheless, in addition to the traditional criteria for fixing the reward as spelled out in Article 13—including salved value, degree of danger, out of pocket expenses, success, time, risk and skill of salvage operation—the amount of the reward will take into consideration “the skill and efforts of the salvors in preventing or minimizing damage to the environment.”20 However, Lloyds Open Form 1990 (LOF 90) contract, based on the Convention, restricted special compensation to “coastal or inland waters or areas adjacent thereto.”
Because of this limiting provision in the LOF 90 and because acquiring special compensation under Article 14 of the Convention proved to be time-consuming, an alternative system for awarding special compensation remuneration, known as the Special Compensation Protection and Indemnity (P&I) Clause (SCOPIC) was developed by salvors, P&I Clubs,21 underwriters, and shipowners. SCOPIC is easy to utilize, with no requirement to demonstrate a pollution threat in a restricted geographic area, and with remuneration based on pre-agreed tariff rates. SCOPIC took effect in August 1999, and the latest edition is SCOPIC 2014. SCOPIC is invoked in about 30 percent of LOF cases and, since its introduction, only nine SCOPIC cases have gone to arbitration out of total of 329.22
We now turn to demonstrating how these salvor practices and traditions could be applied within the space context, while taking account international space law and practice.
Cleaning up space-environment contamination with space salvors
As mentioned above, our modern way of life and our future space plans are being threatened by a space contamination known as orbital debris. One option for clearing away this debris, following the maritime analogy, is to employ commercial space salvors and pay them rewards (“bounties,” if you will) for safely clearing debris from working orbits. A single launching State Party to the 1967 Outer Space Treaty (OST) could target its own debris object in a single-State mission, or multiple launching States could be involved in debris removal operations or programs.
Salvors will have several options for cleaning up orbital debris, including de-orbiting the debris, moving debris to safe “junkyard” orbits for later salvage, or refueling, repairing, or refurbishing defunct spacecraft via on-orbit servicing (OOS). Such servicing by space salvors could also be used to extend the life of functioning spacecraft in danger of becoming non-operational. If two or more launching States join to implement a debris removal operation using a maritime salvor model, the foundation could be laid for the establishment of collaborative customary international law involving ADR.
Of course, there are legal and practical considerations that must be considered before space salvors are unleashed to provide ADR. Chief among legal hurdles are issues of ownership (i.e., jurisdiction and control) and liability as defined by current international space treaties. Arguably the most daunting practical question is how to fund the technologies and systems needed for safe ADR and space maintenance and the payment of salvor rewards.
Let us take on the legal issues first. Article VIII of the OST decrees that the nationally registering launching State retains “jurisdiction and control” (i.e. ownership) of any launched spacecraft or component part. The Convention on Registration of Objects Launching into Outer Space (Registration Convention) contemplates bilateral or multilateral agreements to establish a State of registry.23 According to Article II of the Registration Convention, “Where there are two or more launching States in respect of any such space object, they shall jointly determine which one of them shall [nationally] register the object.”
Although the registry (and therefore ownership of the launched spacecraft and its parts) cannot be transferred to a non-State entity, the transfer of registry to another State Party is not unheard of. The United Kingdom, for example, was the original State of Registry for several satellites which they transferred to the People’s Republic of China as part of the 1997 transfer of Hong Kong. At the time, the UK informed the United Nations that it ceased to be the State of Registry, and China confirmed to the body that it should be considered the State of Registry.24 However, because a commercial space salvor cannot be a sovereign nation, the salvor would be unable to register as owner of a satellite. Regardless, transfer of ownership does not affect the liability regime.25
To understand why ownership does not affect liability we must look at the launching State construct of Article VII of the OST, Article V of the Convention on International Liability for Damage Caused by Space Objects (Liability Convention),26 and the international responsibility provision of Article VI of the OST.
Article VII of the OST identifies four possible launching State categories:
- the State that launches the object or spacecraft;
- the State that procured the launch;
- the State from whose territory the object was launched; and
- the State from whose facility the object was launched.
Article VII also makes it clear that a State Party in each category can be “internationally liable” for damage to another State Party. The Liability Convention with Article V makes clear that each of these so-defined launching States remains “jointly and severally liable” for any damage done by the object or spacecraft the Treaty deems it has launched.
Layered on top of the launching State concept is the mandatory “authorization and continuing supervision” provision, contained in Article VI of the OST, making every State involved in a space activity bear international responsibility for national activities, including those carried on by non-governmental entities. As a result, a State which is not considered a launching State under the OST may still be held liable if the owner or operator of a space object is a national of that State. Thus, while the registry is a useful tool for identifying relevant space actors, it is only the beginning of the inquiry as to what nations may be impacted in a salvage mission.
The liability inquiry is especially important as salvage missions will necessarily require proximity operations. A salvage vehicle, whether designed simply for ADR or for the more complex functions of OOS, will likely be more “accident prone” than a conventional spacecraft as it, on most occasions, will be moving through orbits to rendezvous with its target. If the ailing or defunct target spacecraft and the salvor nationals are launched from the same State and properly registered as such, any liability issues that may arise will be dealt with under the national laws of the affected State.
However, if multiple States are involved, the liability implications (and complications) broaden considerably. Pursuant to Articles VI and VII of the OST, every State which can be considered a launching State, and the citizen-nation of the salvor itself, is internationally liable for damage the salvor vehicle does to the object of another State Party.”27 Article III of the Liability Convention indicates that launching State liability is absolute if damage is done on Earth or to aircraft in flight but based on fault if damage occurs elsewhere than on the surface of the Earth. Thus, damages resulting from any on-orbit accident will be based on fault. It is likely that the liability of the citizen-nation of the salvor for on-orbit damage will also be based on fault.
With all this in mind, one can foresee an instance wherein a salvor organized in State A services a satellite manufactured by an entity organized in State B, registered in State B. Assume the salvor is launched from the territory of State C and the target satellite was launched from State D. Should damage occur on the ground of State E, States A, B, C, and D are jointly and severally liable. If the damage occurs to a space object of State E, in orbit, liability is assigned by fault. It is not difficult to imagine the political and diplomatic morass that could arise in respect of any given commercial salvage mission. Left standing, such liability complications would certainly be enough to dissuade those who might otherwise invest in a salvage company.
Is there a way around this ungainly and diplomatically fraught process while preserving the “bounty” model?
Like the Registration Convention, the Liability Convention permits States to enter into bilateral and multilateral agreements addressing issues of liability. The International Space Station Intergovernmental Agreement28 is a good example of States changing the nature of their liability to one another under specific circumstances. The cross-waiver of liability provision in Article 16 of that agreement also covers contractors and subcontractors as well as users and customers affiliated with the partner States. Subsection 3(c) of the Article makes it clear that the cross waiver includes “a cross waiver of liability arising from the Liability Convention.”29
With the cross-waiver of liability agreement option in mind, assume that the salvor company is incorporated in Launching State A and the target derelict upper stage rocket was launched from and nationally registered in Launching State B. Also assume that Launching State A has declined to accept registry of the derelict satellite. Instead of transferring title to the space salvor, Launching State B could instead license the commercial salvor as its “agent.” Launching State B, as state of registry for the derelict upper stage, would thus retain jurisdiction and control of the operation, and its agent could then legally act upon the vehicle. Launching State A, however, would launch the salvor’s spacecraft, nationally register the launch, and maintain jurisdiction and control over the salvage situation as well. In this multi-liable-party scenario, a cross-waiver of liability agreement can help clarify the reach of liability among all the parties, including parties beyond State A or B who might have spacecraft near the salvage action and who therefore might be involved should there be an accident.
Of course, if the licensed salvor (as State A’s agent) manages to safely deorbit or move the derelict upper stage to a salvage orbit without damaging any other spacecraft, it could receive “special compensation” for clearing away an environmental hazard, as in the maritime situation, and finding liability would not be part of the situation. Embarking now on these types of missions could begin to establish customary international law for bilateral cooperation, especially if repeated. If the derelict upper stage happened to be manufactured by a company organized in State C, then multiple launching States would be involved and the successful clearing away of the environmental hazard would help to establish customary international law for multilateral cooperation.
Starting with bilateral and multilateral efforts to clear out non-sensitive upper stages could build sufficient geopolitical trust so that more sensitive spacecraft, such as satellites, are taken on as targets. Ideally, bilateral and multilateral collaboration to deal with a common threat like orbital debris would contribute a generally calming influence among nation states. At the very least, in the face of other geopolitical issues tending to aggravate geopolitical tensions, any countervailing influence should be welcomed by all.
How will we pay for ADR?
The above sample scenarios would be unrealistic without a source of funding for developing and maintaining the technologies, rewards and bureaucratic systems, which will be needed. Where will the money come from?
Let us not fool ourselves. We in industrialized societies have thoughtlessly allowed dangerous garbage to collect in space, thus finally cornering ourselves in a “pay now or pay (much) more later” situation. Even without launching another satellite, with time there will be more collisions between multi-ton bodies and more catastrophic breakups, and cleaning up the mess will cost us all more. But the situation is much worse because of the 20,000 or so new satellites planned for launch within a few short years. Satellite-services users (i.e., nearly all of us in modern industrial societies) will likely fault their political leaders for loss of services and complain stridently to them. Under these non-optimum conditions, those same leaders will have to scramble to collect funds and organize the cleanup. It behooves us all to adequately fund an international ADR campaign now to avoid this kind of situation.
In coordination with spacefaring entities worldwide, funding for ADR could come from general government revenues, minimal launch fees, and/or minimal orbital “parking” fees imposed on companies launching new satellites into Earth orbit.30 Minimal orbital-use fees would also have the effect of inducing satellite companies to attach devices to their satellites to deorbit them shortly after end of mission or when they become disabled, without specific time-deadline regulation.
A fourth potential source of revenue, at least to help fund ADR in orbital regimes used by commercial satellites, could come from the end users of satellite services. Because the satellite service industry already generates more than $127 billion annually in gross revenues, a one cent per dollar fee on end-user bills would hardly be noticed by consumers. Yet such a fee would generate over $1 billion annually to help fund the cleanup in orbital bands used by commercial satellites. Although commercial satellites are currently located primarily in GEO, soon 20,000 or so new commercial satellites will be launched into MEO and LEO to provide broadband services. Under these new conditions, the end-users of satellite services will feel it appropriate that such funds are used to maintain the satellite services they need and enjoy.
No international entity yet exists to collect and allocate funds for the massive ADR and maintenance that needs to be undertaken. Yet such an entity must be created as soon as possible. Article IX of the OST states in pertinent part that “In the exploration and use of outer space…States Parties to the Treaty shall be guided by the principle of cooperation and mutual assistance and shall conduct their activities…so as to avoid their harmful contamination…and where necessary shall adopt appropriate measures for this purpose.” Article IX goes on to state that “If a State Party to the Treaty has reason to believe that an activity…would cause potentially harmful interference with activities of other States Parties…it shall undertake appropriate international consultations.” (Emphasis ours.)
Surely the growing threat of orbital debris represents harmful contamination and potentially harmful interference with the activities in space of other States Parties. Surely, also, the time has come for international consultations to address the threat of orbital debris with appropriate measures, such as the creation of an international entity to collect and allocate funds for the vast ADR that must be undertaken so that we may continue to avail ourselves of the benefits of space activities.
Legal and financial considerations are dampening efforts to develop efficient ADR services. We urge States to follow the maritime example and work with each other and private ADR service providers within and around the bounds of our imperfect laws to establish a customary practice that will ultimately evolve into settled law. More generally, we call on the international space community, both public and private, to recognize the threat before us and to address it through collaborative effort. By utilizing commercial salvors in public-private partnerships to carry out ADR, civil institutions will be strengthened and space commerce will benefit, creating new jobs and technologies and strengthening the involved Earth economies generally.
Along the way, however, daunting liability, regulatory, financial, and policy issues will need to be addressed.31 Moreover, effective ADR cannot operate in isolation from comprehensive STM, entailing enhanced SSA and orbital debris mitigation.32 The insurance industry will have also to play a major part, and an international arbitration body and possibly an international court will need to become part of the system. As in the maritime salvage context, customary international law and related practices, such as contracts for cleaning up and maintaining a clean and safe space environment will need to be standardized. Also, as in the above-mentioned SCOPIC case, salvor remuneration should evolve until they are based on pre-agreed tariff rates. Finally, all standard contracts and practices and customary international law for ADR and salvage of orbital debris will likely need refinement and codification in a Convention, as in the case of maritime salvage law.
- Wang, Brian. “Total global satellite plans could have around 20,000 satellites in low and mid earth orbits in the 2020s.” Next Big Future, 4 March 2017. Also see Messier, Doug. “SpaceX Wants to Launch 12,000 Satellites,” Parabolic Arc, 3 March 2017.
- Brodkin, Jon. “SpaceX’s worldwide satellite broadband network may have a new name: Starlink,” Ars Technica, 20 September 2017.
- Werner, Debra. “Hazardous Intersection,” SpaceNews, 11 September 2017
- Phipps, Claude & Christophe Bonnal. “A spaceborne, pulsed UV laser system for re-entering or nudging LEO debris, and re-orbiting GEO debris,” Acta Astronautica, 118 (2016) 224 – 236.
- UCS Satellite Database, last revised 11 April 2017.
- Pardini, Carmen & Luciano Anselmo. “Post-disposal orbital evolution of satellites and upper stages used by the GPS and GLONASS navigation constellations: The long-term impact on the Medium Earth Orbit environment,” Acta Astronautica, Volume 77, August–September 2012, Pages 109-117.
- De Selding, Peter B. “ViaSat and O3b, now distant neighbors, eye confrontation in medium-Earth orbit,” SpaceNews, 21 November 2016.
- Howell, Elizabeth. “What Is a Geosynchronous Orbit?”, Space.com, 24 April 2015.
- McNight, Darren; Kessler, Donald. “We’ve Already Passed the Tipping Point for Orbital Debris,” IEEE Spectrum, 26 September 2012
- Phipps, Claude, et al. “Removing Orbital Debris with Lasers,” 2011.
- For a national perspective on a comprehensive Space Traffic Management system see For policy recommendations from the National Space Society, see this NSS white paper
- UNCOPUOS, the Inter-Agency Space Debris Coordination Committee (IADC), and major space nations have developed guidelines for orbital debris mitigation. However, State Parties to the Outer Space Treaty do not always enforce them and all allow 25 years of “free parking” in orbit after a satellite becomes defunct, as part of the current guidelines.
- Secure World Foundation. Handbook for New Actors in Space, pg. 35, 2017 Edition.
- Bennett, James C. “Proposing a ‘Coast Guard’ for Space,” The New Atlantis, Winter 2011.
- Lloyds Open Form and the Special Compensation P&I Clause (SCOPIC).
- International Convention on Salvage, 1989.
- A Protection and Indemnity or P&I club is a non-governmental, non-profitable mutual or cooperative association of marine insurance providers to its members, consisting of ship owners, operators, charterers and seafarers.
- “No cure – no pay,” The International Salvage Union.
- “Convention on Registration of Objects Launched into Outer Space”
- Viikari, Lotta, The Environmental Element in Space Law, 2008, p.77.
- “Satellite Ownership Transfers and the Liability of the Launching States,” IISL/ECSL Symposium, 19 March 2012
- “Convention on International Liability for Damage Caused by Space Objects”
- “Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies”
- See Article 16 and 17 of SPACE STATION Agreement Between the United States of America and Other Governments, 1998.
- Ibid at Article 16(3)(c).
- Such fees would be imposed only after significant international parties, including Russia, China, ESA, India, and Japan agree to abide by such a fee system.
- For policy recommendations from the National Space Society, see this NSS Space Guard position paper and this orbital debris position paper.