Space Debris: A threat just beyond the horizon

With the advent of mega-satellite constellations like SpaceX´s Starlink, who plan to launch more than 12,000 satellites, space debris is increasingly becoming an issue.1 Satellites break, lose control capability, or have to be turned off. In addition, anti-satellite tests generated large clouds of debris in space, even endangering the lives of astronauts on the ISS. We urgently need clear and internationally valid rules and regulations regarding space debris. And furthermore, innovative ideas on how we can actively remove space debris. RFA proposes three approaches to solving this pressing problem.

 

Space junk orbiting around earth - Conceptual of pollution around our planet (Texture map for 3d furnished by NASA -  http://visibleearth.nasa.gov/)

The consequences of space debris

A satellite, once in low-Earth orbit, can continue to orbit the Earth for a long time. Up to a certain height, individual air molecules do slow it down, so the satellite eventually burns up in the atmosphere. But this process can take decades or even centuries. And so, it’s getting more and more crowded: while the number of objects in Earth orbit has nearly doubled from about 15,000 objects larger than 10 cm in 2011 to more than 30,000 objects in 2021, the number of objects re-entering Earth has remained relatively stable at about 550 per year over the same period.2 There are estimated to be more than 130 million objects smaller than one centimeter that cannot be tracked but travel at five times the speed of a bullet.2 These can be pieces of old satellites, but also e.g. small fragments of paint that come from rocket launches. Take Starlink, for example: Given the large number of objects located in Starlink’s 550 km orbit, the journal “Nature” estimates that there is about a 50% chance of one or more collisions per year.3 In addition, each collision increases the number of objects in orbit, which in turn increases the probability of another collision. This vicious cycle is called “The Kessler Syndrome.” A study conducted by NASA in 2005 concluded that even a complete halt to satellite launches at that time would not have been enough to completely prevent a possible Kessler Syndrome.4 In the most extreme case, space debris could reach the point where rocket launches from Earth become virtually impossible because of the high likelihood of collisions in which the rocket is hit by debris before it even reaches orbit.

Number of objects in orbit by type. Source: ESA (2)

The emergence of mega-satellite constellations

While such a scenario is currently not foreseeable, the number of satellites launched into orbit has increased rapidly due to the emergence of mega-constellations. In the last five years alone, the number of active satellites has nearly quadrupled – from 1.466 in 2017 to 4.877 in 2021.5 It is easy to see the dangers of this trend. However, concluding that satellites and mega constellations are dangerous and therefore should not be launched leaves out the potential positive impact that satellites and large constellations can and do have on our daily lives. They provide internet connectivity in remote areas. They help detect forest fires in large countries like Australia. They enable the optimization of logistics routes. They make a vital contribution to environmental protection. And only with satellites are we able to fully understand and predict the tipping points in the fight against climate change. In short, satellites and constellations are critical to gathering data about our Earth. So, what is a possible solution? One thing is obvious: we need clarification when it comes to rules and regulations in space.

Tackling the problem

Examples of what these regulations must include and what solutions might look like already exist today and in abundance: For one thing, most government agencies such as NASA or ESA already track space debris themselves and make this information available to third parties. This information can and is already being used to avoid collisions. For another, research is underway to develop tools and devices that can actively or passively remove dead satellites from orbit. A NASA study also concluded that the LEO environment could be stabilized if up to 5 high-risk objects were actively removed from orbit each year.4 Companies like Astroscale are already working on active space debris removal, while companies like SENER Areoespacial are working on solutions for passive space debris removal.6 ESA has planned the first mission for active disposal of an old satellite in collaboration with ClearSpace for 2025.7 While the solutions are not yet commercially viable, they are available and will become more common as launch costs fall and access to space is democratized.

ClearSpace-1 prepares to reenter with Vespa. Source: ESA (7)

And now? Let's get to it.

First and most importantly, we need tighter rules and regulations for space debris. These rules must be enforced internationally by an organization that has the ability and authority to monitor the international space environment and impose sanctions or fines in the event of violations. In the interest of equal rights for all space-faring nations, the problem of space debris must be tackled together at its root and solved in a sustainable manner over the long term. National go-it-alone efforts, however well-intentioned, make little sense. Everyone needs to work together and clearly regulate how much space debris an individual organization can produce, how long an object can stay where in orbit, and how and when it must be removed. Internationally recognized institutions must be established or expanded in their competencies to take on this responsibility. In addition, they must oversee the efforts of all spacefaring nations to remove their retired satellites from orbit. We propose a maximum time frame of five years for this instead of the 25 years that the FCC currently adheres to.8

 

Secondly, we need financial and political support for the companies developing the tools and devices with which to de-orbit satellites. However, this support should not take form of subsidies. Instead, ESA, for example, should award fixed-price contracts that companies can bid on. Whoever offers the most compelling and effective solution should then be awarded the contract. Objects such as those identified by Darren McKnight in his paper “Identifying the 50 statistically-most-concerning derelict objects in LEO” could be an initial target of such contracts.9 The industry will then develop a market for such services. Since space debris is considered a common problem, without initial financial incentives, a market cannot develop, which would lead to fewer space debris removal solutions. In short, we need to build an industry that produces tow trucks for space, whose services can then be purchased by states or institutions. After a successful primary mission, orbital stages can also be equipped for this purpose, which is how we plan to do it, for example.

 

Last but not least, there should be an international, standardized and public database for debris. Debris tracking solutions should be contributed by all and based on an international standard. This public database should be fed with both ground-based and space-based data, thus contributing significantly to reliable Space Situational Awareness. Based on this database, not only is safe travel to space possible in the decades to come, but also sustainable Space Traffic Management (STM) – to everyone’s benefit.

 

Conclusion

Yes, the challenge is a big one. And yes, economic interests have to take a back seat to a certain extent. But as with climate change, the same is true here: If we don’t act today, it will be even more difficult, if not impossible, to solve this problem 20 years from now. So we should act together, decisively and, above all, now.

About Rocket Factory Augsburg:

Rocket Factory Augsburg was founded in 2018 with the vision to enable data generating business models in space to better monitor, protect and connect our planet Earth. Against this background, the company’s goal is to offer launch services of up to 1.300kg into low Earth orbits and beyond on a weekly basis at unmatched prices. With this, RFA wants to democratize access to space and reduce the launch costs in the space industry. The RFA ONE launch service combines three key competitive advantages: A customer focused service with precise in-orbit delivery and a high degree of mission flexibility through its orbital stage; at a highly competitive price; made possible by superior staged combustion technology, low-cost structures and usage of industrial components.

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