David Zamora is the chairman of the Space Data Association. He contributed this article to Space.com's Expert Voices: Op-Ed & Insights.
The commercialization of space is well underway, and as a result, Earth’s orbit is becoming ever more congested. The current number of active satellites in orbit stands at around 16,000, according to the European Space Agency( ESA), and this number is expected to jump close to 60,000 by 2035, Novaspace projects. While it’s not always given the recognition it deserves, space has fast become a critical infrastructure layer, underpinning nearly all systems that enable modern life as we know it. Therefore, it’s critical that a safe and clean operating landscape is maintained.
Yet this is becoming increasingly challenging, particularly given that, alongside the rapid increase in space traffic, there are also more than 1.2 million pieces of debris over 1 centimeter (0.4 inches) cm in Earth’s orbit, each of which could damage satellites and spacecraft and potentially cause disastrous consequences. With the number of active satellites and debris objects in space continuing to increase, the space environment is under growing pressure.
Balancing expansion with sustainability
Space was once the sole domain of nation states, but this is no longer the case. As technology has advanced, launch costs have decreased, and satellites have become more efficient, smaller and cheaper to build. These changes have democratized space, resulting in a massive increase in space traffic, not least constellations in low Earth orbit (LEO) that comprise thousands of satellites.
Plans are underway to further expand these constellations, and new and even bigger constellations are also expected to launch in the coming years. Added to that, we’re also likely to see the first space-based data centers within the next few years, which may well mark the start of the wholesale shift of data centers from Earth to space, which will further add to the congestion already being felt.
To ensure that space continues to meet our current and future needs, this continued expansion must happen in a sustainable way. Maintaining a safe and clean landscape is more important than ever before, and mitigating the impact of space debris is critical to that effort.
Maintaining a safe environment
Mitigating the impact of debris involves a multipronged approach. Whether intentional or unintentional, the creation of new space debris by future space missions must be minimized as much as possible. This applies during launch, operation, and end of life phases, and satellites and other spacecraft need to be designed with this in mind. Additionally, satellites that are no longer active should not remain in orbit for extended periods, because this only increases the chance of collision events which would create new debris. The standard rule has been 25 years, but there are recommendations now that this should be lowered to five years.
Also critical is the prevention of in-orbit collisions between active satellites and other objects. This is only achievable through effective Space Situational Awareness (SSA) and Space Traffic Coordination (STC) systems. SSA maps out and characterizes objects in space (both satellites and debris), determining their location, trajectory and velocity, while STC actively manages the space traffic identified through SSA to prevent collisions. When a conjunction is probable, SSA/STC service providers alert the operators involved, who then decide whether to undertake a collision-avoidance maneuver.
Extending the operational life of satellites is another important aspect of debris mitigation because it reduces the need for so many new launches, thereby reducing the likelihood of more debris being created. Innovations such as electric propulsion systems that allow for greater maneuverability and extended mission durations are part of the solution, as is in-orbit servicing, maintenance and refuelling.
While these strategies focus on preventing new debris from being created, we also need effective methods for removing existing pieces of debris. This is a rapidly growing sector attracting much investment. Debris-removal technology being developed ranges from physical capture and tethered deorbit to destruction with ground and space-based laser ablation and plasma systems, as well as the emerging concept of mining debris to extract metals and gases for in-orbit processing to feed into the circular space economy.
How stakeholders are responding
The UN views space safety and space sustainability as urgent priorities. Its treaties and agreements focus on preserving the peaceful, safe, and sustainable use of outer space, preventing collisions, managing space debris, and ensuring responsible operations. Governments, space agencies and international organizations are also strengthening their focus on space sustainability.
ESA has launched its Zero Debris strategy, which is aimed at achieving a debris-neutral orbital environment by 2030. As part of this approach, ESA has updated its debris mitigation requirements and standards that will govern how its missions are designed, built, flown and disposed of. It also sets requirements for any company or institution that works with ESA on its missions.
In the U.K., the UK Space Agency is also taking a proactive role in space safety and sustainability through its Active Debris Removal (ADR) program and through the development of space sustainability standards in partnership with industry. It is also in the process of developing a space sustainability strategy to ensure a coordinated approach to sustainable practices in space.
On the other side of the pond, NASA’s Space Sustainability Strategy identifies five key challenges that are felt nationally but also within the wider space community. These include the absence of a single framework for space sustainability that has been accepted by the space community and the fact that space sustainability may be in tension with other mission interests. The strategy defines six goals that are intended to address each of the challenges alongside corresponding objectives to guide NASA’s achievements of the goals.
The U.S. is also building on the National Orbital Debris Mitigation Plan, which was released in 2022, with the Orbital Sustainability (ORBITS) Act. The Act, which has been introduced to the Senate but not yet been enacted into law, seeks to establish a program for the active remediation of orbital debris as well as requiring the development of uniform orbital debris standard practices. The Office of Space Commerce has also developed TraCSS (Traffic Coordination System for Space) to provide basic SSA data and services to civil and private space operators in support of spaceflight safety, although the system is currently in beta mode.
The International Standard Organisation (ISO) is also working on a standard for STC (Space Traffic Coordination) so that SSA activities can be standardized. Titled Space Systems — Space Traffic Coordination (STC), the standard is moving toward final publication, and its core focus is on establishing baseline protocols, data exchange formats and operational requirements for space safety, on-orbit conjunction assessment and collision avoidance.
Beyond today
While these strategies are certainly moving the industry in the right direction, there is a real need to act quickly. Success will rely not only on speed, but also on sustained and collaborative effort, as well as engagement from all space users. The decisions made and actions undertaken over the next decade will shape the space environment for generations to come.
As to whether sustainability becomes a core principle rather than an afterthought, that remains to be seen. There is, however, reason to be optimistic.
