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A Reality Check on Space Sustainability

Author: TH Anand Rao, Senior Fellow, Centre for Air Power Studies

Keywords: Space Junk, debris, orbits, constellations, sustainability

That space is infinite; is now a paradox. The infiniteness of space is of little use to humankind, and the useful space is seeing an expansion of human activity beyond the blue skies. This useful space referred to is the orbital region of the Earth, specifically the low earth orbit (LEO) and geostationary orbit (GEO). The Earth’s orbits are getting packed with satellites, rocket bodies, and debris of all sizes. We have already crossed the point of no return, where despite efforts to limit the creation of new debris and remove some debris, the population of unwanted junk in space will only increase. It is feared that the breaking point will be reached sooner or later. In fact, Kessler’s Syndrome is no longer in theory but is around the corner.

The near-miss event on January 27, 2023, should ring the alarm bells. This conjunction event involved a defunct SL-8 rocket body and a dead satellite, Cosmos 2361, both of Russian origin. The near miss occurred at an altitude of 984 km with a miss distance of just 6 metres. This was a very close call. Given the margins of accuracy in conjunction analysis, it is purely good luck that the objects did not collide. Otherwise, the event was very close to triggering a cascading ripple effect, which could have resulted in the worst-case scenario of generating thousands more pieces of space debris.[1]

As the launches into space increase with each passing year, the satellite population is growing rapidly. With 174 launches, the world witnessed the highest number of launches in 2022 as compared to the previous years. 2022 also saw the highest number of satellites being added to orbit, most of which were small satellites in LEO. There was an increase of around 32.2 per cent in small satellites in comparison to the small satellites launched a year earlier.[2] There are now 7200 active satellites in orbit, and around 32,300 objects are being tracked by space surveillance networks.[3] Debris accounts for a major portion of objects being tracked. The trackable debris represents only a fraction of the total debris in space, as many of the smaller debris cannot be tracked. Sadly, as the satellite count is set to grow higher every year, the debris count will also increase, and there may be no way to stop this growth. It is slowly becoming unclear as to who will take control of this emerging disaster in space. Regulatory control is clearly inadequate to deal with the overcrowding of the orbital region.

Issues related to orbital crowding and the proliferation of debris are being viewed under the ambit of space sustainability, which has gathered momentum in recent years. The focus has been on LEO, which has been in demand for satellite constellations. While SpaceX’s Starlink and Sunil Bharati Mittal backed OneWeb are the early birds in exploiting connectivity through LEO, many more commercial entities and state space agencies are getting set to explore this attractive option. If all these planned satellite constellations are put into orbit, the satellite population will touch 1,00,000 in a decade.[4] Adding to the potential mess, a commercial company by the name of e-Space has declared filings for over 100,000 communication microsatellites, which may go up to 300,000.[5] Rwanda’s space agency, which is a new entrant into space, has also filed for 27 orbital shells for two satellite constellations comprising a total of 327,320 satellites.[6] Although the numbers may not mean much if the satellites are spread across the orbital altitudes, these numbers become significant when concentrated in a limited altitude band in the proximity of the 600-1000 km altitude band, which happens to host the most crowded orbits in LEO. It appears incongruous that the Starlink constellations have been placed on the fringes of this crowded orbital zone. Although the Starlink orbits have no encumbrance, any collision with debris or implosion of satellites will have an effect on nearby orbital bands. The gravity of the situation can also be gauged by the number of conjunction alerts received. Starlink alone is responsible for almost half the close encounters, which amounts to around 1600 conjunction alerts (closer than 1 km) in a week.[7] The situation will definitely get worse when all the planned constellations are put into orbit.

With the developing situation in LEO, space is definitely not sustainable. The silver lining, however, is that people are thinking about ways to avoid a disaster. The near-earth space is finite and should be treated as a finite resource. This finite resource’s planning, coordination, and management can only happen through effective and stringent regulations. It is analogous to how air traffic is being managed in international airspace. Space is certainly a global common, but that doesn’t give any state the freedom to exploit space by disregarding the interests of other states. This is codified as the principle of ‘due regard’ in Article IX of the Outer Space Treaty.

The issue of sustainability in space is being addressed through multiple means, which include deliberations at UN-mandated working groups to arrive at norms of behaviour in space, assessment of debris mitigation guidelines, improving situational awareness in space, discussions on space traffic management, active debris removal, and so on. These are all essential steps in achieving a safe and sustainable space environment. The need of the hour is to fast-track the actionable items on the agenda. While the measures stated will give long-term solutions, there is an immediate need for some innovative approaches to achieve sustainability goals in the short term through practical measures.

The idea of introducing a ‘Space Sustainability Rating’ by attaching a score to represent a space operator’s sustainability index was mooted by the World Economic Forum’s Global Future Council on Space Technologies. This is an incredible tool for users and customers to assess the sustainability contribution of a commercial space operator prior to a contract being awarded. Sustainability measures will get implemented faster when the people involved see visible benefits that affect them directly. So, even tax benefits could help, just as they do for going green with electric vehicles. But for that, the governments must be convinced, and it should happen on a global scale. Another measure to avoid leaving debris in space is to promote reusability, which is a phenomenon gaining traction. It’s not just rockets that need to be reusable, but satellites too. Satellites need to be given life upgrades at the end of their mission life to prevent newer satellites from being launched. This has been made possible by ‘on-orbit servicing,’ which has opened up the possibilities of refuelling, repairing, and inspecting satellites. Payloads onboard satellites should be remotely programmable to accept software upgrades. Satellites should also be compatible with de-orbit servicers to put them in safer orbits at the end of their life or to push them towards an atmospheric burn. By far, the most effective way to achieve sustainability is by avoiding collisions with existing space debris. This can be achieved by making a real-time and complete picture of Space Situational Awareness (SSA) data available to all users. To make this happen, SSA data needs to be tapped from all sources and fed into a common space situation picture which should be controlled by a multinational organisation under a UN mandate. Transparency in SSA is vital to ensuring safety and sustainability in space.

Finally, the way events unfold in the next decade will have a bearing on the future of space. Past actions have a significant bearing on what to expect in the future. It’s not difficult to see that some orbits will become unusable in the future as they will get saturated with satellites and debris. It can also be inferred that saturation in some orbital shells will have a ripple effect in increasing conjunction assessments and raising the risks of a collision significantly while the available orbital slots in other shells get progressively occupied. Eventually, a stage will come when we will not be able to prevent undesired outcomes even with enhanced regulations, SSA, and collision avoidance mechanisms.

There is a need to do an inverse analysis to arrive at desired outcomes on space sustainability issues. If we fast forward to a scenario that would exist in 2050 and work backwards, it will become apparent that time is not on our side. It also needs to be emphasised time and again that what goes up – into space – doesn’t necessarily come down, as it does in the atmosphere. So, one must be sure, before launching an object into space, that it actually needs to go there. Some issues do get resolved when they show up as extremes. Every near-miss event and every kinetic anti-satellite test which have the potential to create additional debris is an extreme event. The global space community should leverage these to agree on legally binding mechanisms to prevent harmful activity in space and collaborate to achieve transparency. There have been many missed opportunities in the past to arrive at more efficient regulatory practices. It is high time the UN-mandated organisations and working groups progress beyond discussions and negotiations and arrive at practical solutions to improve safety and sustainability in space.




[1] Brett Tingley, “2 big pieces of space junk nearly collide in orbital bad neighborhood”,, January 28, 2023,, accessed march 20, 2023.

[2] Number of orbital space launches worldwide from 1957 to 2022, Our World in Data, , accessed March 21, 2023.

[3] “Space debris by the numbers,” The European Space Agency, December 22, 2022,, accessed March 21, 2023.

[4] Jessica Heim, “Satellites and space junk may make dark night skies brighter, hindering astronomy and hiding stars from our view”, The Conversation, March 20, 2023,, accessed March 22, 2023.

[5] Jon Brodkin, “Firm planning 100,000 satellites claims it will “clean space” by capturing debris”, Ars Technica, February 08, 2022, , accessed March 21, 2023.

[6] “Rwanda files at ITU for nearly 330,000 satellites”, Spacewatch Africa, October 22, 2021,, accessed March 22, 2023.

[7] Dan Swinhoe, “SpaceX’s Starlink accounts for ‘half of all satellite near misses”, Data Centre Dynamics, August 23, 2021,, accessed March 22, 2023


(Disclaimer: The views and opinions expressed in this article are those of the author and do not necessarily reflect the position of the Centre for Air Power Studies [CAPS])

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