by Dr Antje Nötzold, Senior Research Associate, Department of International Politics, Chemnitz University of Technology, Germany
After land, sea and air, space has become the fourth dimension of human civilisation and a day without space is virtually impossible. Space-based systems are not only militarily essential, of considerable economic value and therefore of strategic importance for every state in the world, they are now indispensable for the daily life of modern societies. So, an increasing number of players – states, companies and private individuals – are aiming for space while Earth’s orbit is not infinite, but rather more and more crowded.
Cluttered with satellites…
While coveted space for new satellites is becoming scarce in the Geostationary Orbit (GEO – 35,786km altitude), the Low Earth Orbit (LEO – 100-2,000km) is heading towards overcrowding. With around 1,400 functional satellites in 2016, this number has increased to approximately 9,500 and is constantly growing. Currently, 20 to 50 satellites are launched per week, with the rapidly growing NewSpace sector of commercial space-based services, particularly in communications and earth observation. Starlink already accounts for most active satellites, with over 6000, and is set to grow to 42,000. In conjunction with other commercial providers, the International Telecommunication Union (ITU) has received requests for up to 70,000 new satellites by the year 2030. Concurrently, countries such as the US (Starshield), China, Taiwan, and Europe (IRIS²) are also planning to set up their own mega-constellations to reduce strategic vulnerability and dependence on commercial players, especially Starlink.
…and man-made waste
In addition to the soon-to-be tens of thousands of satellites, near-Earth space is overcrowded with man-made junk. Space debris is defined as any human-made object in orbit that no longer serves a useful purpose, created by the loss of function, collision or explosion of formerly functional space objects. This includes old rockets, spacecraft fragments, dead satellites and pieces from collisions. Although over time, these objects descend into lower orbits and enter the Earth’s atmosphere, the problem will not solve itself. At an orbital altitude of 800km, objects are expected to remain in orbit for up to 150 years before re-entering the atmosphere. In addition to around 36,000 recorded parts larger than 10cm in diameter, statistical models estimate that there are around one million pieces of debris between 1 and 10cm, and 130 million fragments between 1mm and 1cm travelling through space at a speed of several kilometres per second. This means that burnt-out rockets as big as school buses orbit at 10 km/s on average, with no brakes or steering wheel. And while we are not able to track objects smaller than 10cm with existing technology, a piece of 1cm in diameter already has the kinetic energy of a hand grenade.
Risk of collision and attacks
85% of the debris is in LEO, where the ever-increasing number of satellites, with their inevitable failures and technical faults, exponentially increases the risk of further space debris, as does the competition between the leading space powers to expand counterspace capabilities to temporarily or permanently disable or destroy their rivals’ satellites. In particular, anti-satellite (ASAT) missile tests have a massive impact. The destruction of the Chinese satellite Fengyun 1C in 2007 generated around 3,500 known pieces of debris, with three-quarters still in orbit, and the debris cloud from Russia’s ASAT test in November 2021 put the International Space Station (ISS) on alert several times.
Non-kinetic attacks using lasers or electromagnetic pulses can also render satellites inoperable and thus pose a threat to other satellites. In 2009, two satellites collided for the first time when the defunct Russian military satellite Kosmos 2251 hit the US communications satellite Iridium 33. Between December 2022 and May 2023, Starlink satellites performed 25,000 collision avoidance maneuvers. This equates to an average of 137 maneuvres per day per satellite. However, not all satellites are capable of this, so NASA was only able to observe a near-collision when an inactive Russian Kosmos satellite missed the US Earth observation satellite TIMED by less than 10 metres on 28 February 2024.
Need for Space Traffic Management (STM)
Consequently, the probability of further collisions is high, with each collision leading to new space debris, which in turn jeopardizes other satellites. This could lead to the Kessler syndrome, which is a cascading increase in the number of small objects in space debris due to random collisions. Once initiated, the cascade would affect all satellites and render the entire orbital altitude unusable. So, mathematically, the current situation in LEO is already a ticking time bomb. Therefore, the implementation of active international Space Traffic Management (STM) is a pressing necessity, which must encompass three fundamental elements.
Space Situational Awareness (SSA)
Firstly, the initial step in ensuring the safety of satellites is to gain a fundamental understanding of the situation in space. International exchange, particularly with the US, which continues to possess the most comprehensive SSA capabilities, remains crucial. Nevertheless, it is essential to build up independent capabilities. The implementation of the EU Space Surveillance and Tracking (SST) capability is an important approach to bundling and linking national capacities, which should be further expanded in terms of technical capabilities, e.g. supplementing the currently purely earth-based sensors with space-based reconnaissance.
Space debris mitigation
Secondly, to prevent further space debris and damage to satellites, it is essential to establish and enforce basic “traffic rules” and standards. Satellites – both governmental and commercial – will increasingly not only possess high maneuvrability, but also other systems such as grappling arms, which can be employed for unfriendly behaviour and the infliction of harm upon other satellites. Thus, the EU proposal for an International Code of Conduct for Outer Space Activities should be pursued with greater urgency. Furthermore, the rapidly growing proportion of – sometimes simply produced – smallsats requires a definition of minimum standards for design and technology, such as maneuvrability or de-orbiting rules, to prevent them becoming or generating further debris. Today, not even all European spacefaring nations, such as Germany, have a national space law to define this. Furthermore, the EU space law, which was announced for early 2024, is unfortunately delayed.
Removal of debris
Finally, it is of paramount importance to actively remove debris. A multitude of possibilities and projects are pursued and already well advanced in research and development, such as robotic arms, lasers or collecting nets. However, two significant obstacles to the de-pollution of space remain. First, these options have a dual-use character and could be used for military purposes against an opponent’s space assets. Consequently, consensus is needed on the definition of a space weapon relating to unfriendly behaviour in space. Second, who is going to pay the bill of active debris removal?
These tasks are challenging and require a common ground between the growing number of actors in space. Nevertheless, the issues must be addressed at the political level in a timely manner if space sustainability is to be secured and space usage made available to all members of the human race and future generations.