Space traffic management: Essential

SPACE TRAFFIC MANAGEMENT: ESSENTIAL YET ELUSIVE?

MATTHEW STUBBS, ASSOCIATE PROFESSOR, ADELAIDE LAW SCHOOL AND CHAIR, SPACE LAW COMMITTEE

INTRODUCTION: THE MIRACLE OF TRAFFIC MANAGEMENT, AND THE MORASS OF UNMANAGED TRAFFIC IN OUTER SPACE

Most of us take traffic management for granted. It is a problem that has largely been solved on the roads, and even in airspace. But it is one of the great unresolved challenges of humankind’s burgeoning use and exploration of outer space.

Once we have learned the rules of the road and obtained a driver’s licence, it becomes second nature to drive on the formed road within the marked lanes, to give way to other vehicles which have the right of way (including at devices such as roundabouts which are designed to use the right of way as an ordering system) and otherwise to follow the various Australian Road Rules, and to obey traffic control devices such as traffic lights. Each of these is an element of the architecture of road traffic management which is essential to our ability to use the road but which we do not stop to think about, except perhaps if we are in a long queue at the traffic lights.

When we fly in an aircraft, we also devote little thought to air traffic management. But typically we fly in aircraft whose pilots are following pre-filed flight plans, with access to standardised information-sharing regimes, using designated air lanes, in aircraft with transponders transmitting identifying information to facilitate radar tracking, whose movements are controlled by active air traffic control in order to reduce the possibility of collision even in congested airspace.1 This is a highly sophisticated system for air traffic management.

In outer space, there is no equivalent system of traffic management. Moreover, an object orbiting at an altitude of 400km (as the international space station does) will be travelling at just under 28,000 kilometres per hour. At that speed, there will be no such thing as a ‘fender bender’ or minor collision. In the absence of space traffic management, James Rendleman has memorably said that satellites in low earth orbit are like ‘cars driving blindly through a corn field, at top speeds, in all directions at once.’2

This is a problem which will only become more acute, as the number of objects in low-earth orbit is increasing exponentially. At the end of 2016, there were just over 2,000 payloads and nearly 10,000 pieces of debris greater than 10cm in size in low-earth orbit.3 By the end of 2021, that had risen to around 6,000 payloads and 12,000 pieces of debris.4 The number of payloads is projected to increase rapidly to 100,000 in coming years.5 The cornfield is becoming much more crowded, and thus collisions much more likely.

EXISTING PRINCIPLES AND PRACTICE: HOW SPACE LAW HAS ORDERED ACCESS TO DATE

To date, users of outer space have relied on a practice which amounts to self-help, and on broad principles whose application to the problem is not entirely clear.

The practice is that, where space domain awareness enables the tracking of objects, it may be possible to calculate the likelihood of collisions between tracked objects. In such a case, a conjunction warning can be issued when a risk of collision is identified.6 If there is such a warning, individual operators will need to choose whether to heed the warning and take evasive action, which necessarily burns fuel and reduces the lifespan of an expensive satellite.7

The limits of this system are easily demonstrable through the example of a major satellite collision. On 10 February, 2009, there was no conjunction warning issued to Iridium that its Iridium 33 satellite was going to pass close to the defunct Cosmos 2251, and publicly available data (of which the operator was unaware) put the risk of collision outside the top 10 conjunction warnings for the day. In fact, the satellites did collide, creating more than 2,000 pieces of space debris greater than 10cm in size, and a great many more smaller pieces.8 This illustrates the problems of the track and avoid system we have today: tracking capabilities leave gaps in space domain awareness, and the lack of data sharing arrangements further hamper the identification of collision risks; and even where risks are identified, there may be limited capacity to respond, and imperfect information may mean that poor judgements are made about the need for response where there is a capability to take evasive action.

The precise application of the legal framework is also uncertain. The Outer Space Treaty of 19679 – the constitution of outer space –10 establishes important principles which guide the exploration and use of outer space. Relevantly, these principles include: • Freedom of exploration and use (art I); • Due regard for the interests of other states and the avoidance of harmful interference with their space activities (where possible) (art 9).

Inevitably, due regard and the avoidance of harmful interference must operate as a limit on the general freedom of exploration and use of outer space. However, it is not clear how the balancing of these considerations is to be carried out in practice.

PRACTICAL PATHWAYS TO THE FUTURE: WALK BEFORE YOU RUN; DON’T BITE OFF MORE THAN YOU CAN CHEW

It is widely accepted that there is unlikely to be a new multilateral treaty establishing a regime of space traffic management.11 This raises the question of what pathways exist for normative development in this important area.

One pathway that can be of considerable value in the international legal arena is the development of relevant ‘soft law’ principles. The best example relevant to space traffic management are the Space Debris Mitigation Guidelines developed under the auspices of the United Nations’ Committee on the Peaceful Uses of Outer Space (COPUOS).12 Although not legally binding, these guidelines are relatively widely followed and provide useful guidance as to the avoidance of the creation of space debris. They only touch tangentially on space traffic management in calling on states to ‘[l]imit the probability of accidental collision in orbit’.13 The development of a soft law instrument is perhaps the most likely means for advancing understandings of the legal contours of effective space traffic management.

What principles should be embodied in any soft law instrument on space traffic management? Two key scholars of outer space law have offered valuable suggestions. First, Paul Larsen has advocated that any normative regime aim to address only civil, and not military, uses of outer space.14 This would parallel many other regimes – for example, the Chicago Convention applies only to civil aircraft, and the International Telecommunications Union regulates only civil access to the radiofrequency spectrum – and is much more likely to lead to engagement by states. Second, PJ Blount has suggested that the best immediate focus would be on what he terms space traffic coordination.15 That is, rather than directly seeking to develop norms regarding traffic management, the first step should be to enhance data sharing with a view to improving general access to space domain awareness. In other words, we need to enhance our capacity to identify key risks of collisions, before we set out in detail what to do once such a risk has been identified (a matter which is already guided by the obligations of due regard and the avoidance of harmful interference, even if their precise application is unclear).

CONCLUSION

Just as we rely on traffic management on the roads and in the air, so we will need traffic management to ensure effective and efficient, or even continued, access to outer space. To achieve an effective regime of space traffic management will require lawyers to think more broadly about norm creation, given that a grand and comprehensive scheme brought to force through the traditional means of a multilateral treaty seems extremely unlikely. Instead, if we seek to develop consensus around non-binding guidelines that would enhance space traffic coordination through the sharing of space domain awareness information, and focus on civil rather than military uses of outer space, there is a realistic possibility that we will start to develop the foundations of the effective regime of space traffic management that will be essential in future if we are to ensure humankind’s continued access to outer space and all the benefits that brings. B

Endnotes 1 See, eg, Corinne Contant-Jorgenson, Petr Lála and Kai-Uwe Schrogl (eds), Cosmic Study on Space

Traffic Management (International Academy of

Astronautics, 2006) 46-52, 55. 2 James D Rendleman, ‘Space Traffic Management

Options’ in (2014) 57 Proceedings of the

International Institute of Space Law 109, 111. 3 European Space Agency, Annual Space

Environment Report (27 April 2017) 22. 4 European Space Agency, Annual Space

Environment Report (4 April 2022) 52. 5 Harry Baker, ‘How many satellites orbit Earth?’ (14 November 2021) https://www.livescience. com/how-many-satellites-orbit-earth. 6 See, eg, Paul B Larsen, ‘Solving the Space Debris

Crisis’ (2018) 83 Journal of Air Law and Commerce 475, 481-2; Danielle Miller, ‘Calling Space Traffic

Control: An Argument for Careful Consideration before Granting Space Traffic Management

Authorities’ (2017) 23(2) ILSA Journal of

International and Comparative Law 279, 283-4. 7 See, eg, Brian Weeden, ‘Billiards in Space’, The

Space Review (23 February 2009) <http://www. thespacereview.com/article/1314/1>; PJ Blount,

‘Space Traffic Management: Standardizing On-

Orbit Behavior’ (2019) 113 American Journal of

International Law Unbound 120, 121-3. 8 Weeden (n 7). 9 Treaty on principles governing the activities of States in the exploration and use of outer space, including the moon and other celestial bodies, 610 UNTS 8843 (entered into force 10 October 1967). 10 Ram Jakhu, ‘Legal Issues Relating to the Global

Public Interest in Outer Space’ (2006) 32 Journal of Space Law 31, 31. 11 See, eg: Blount (n 7) 123-4; Brian Israel, ‘Treaty

Stasis’ (2014) 108 American Journal of International

Law Unbound 63; Saadia M Pekkanen, ‘Governing the New Space Race’ (2019) 113 American Journal of International Law Unbound 92. 12 Space Debris Mitigation Guidelines of the

Committee on the Peaceful Uses of Outer

Space, UN Doc A/62/20 Annex. 13 Ibid guideline 3. Similarly, the proposed Draft

International Code of Conduct for Outer Space

Activities (2014) <https://eeas.europa.eu/sites/ eeas/files/space_code_conduct_draft_vers_31march-2014_en.pdf> would require States to

‘minimise the risk of accidents in space’. 14 Paul B Larsen, ‘Minimum International Norms for Managing Space Traffic, Space Debris, and

Near Earth Object Impacts’ (2018) 83 Journal of

Air Law and Commerce 739. 15 PJ Blount, ‘Space Traffic Coordination:

Developing a Framework for Safety and

Security in Satellite Operations’ (2021)

Space: Science & Technology https://doi. org/10.34133/2021/9830379.