The Case for Space Environmentalism (2204.10025v1)

Abstract: The shell bound by the Karman line at a height of 80 to 100km above the Earth's surface, and Geosynchronous Orbit, at 36,000km, is defined as the orbital space surrounding the Earth. It is within this region, and especially in Low Earth Orbit (LEO), where environmental issues are becoming urgent because of the rapid growth of the anthropogenic space object population, including satellite "mega-constellations". In this Perspective, we summarise the case that the orbital space around the Earth should be considered an additional ecosystem, and so subject to the same care and concerns and the same broad regulations as, for example, the oceans and the atmosphere. We rely on the orbital space environment by looking through it as well as by working within it. Hence, we should consider damage to professional astronomy, public stargazing and the cultural importance of the sky, as well as the sustainability of commercial, civic and military activity in space. Damage to the orbital space environment has problematic features in common with other types of environmental issue. First, the observed and predicted damage is incremental and complex, with many contributors. Second, whether or not space is formally and legally seen as a global commons, the growing commercial exploitation of what may appear a "free" resource is in fact externalising the true costs.

• The paper proposes a holistic framework that treats orbital space as a critical ecosystem, calling for environmental regulatory measures akin to terrestrial policies.
• It highlights the exponential growth of satellites from megaconstellations and assesses associated collision risks and debris accumulation.
• The study introduces a 'Space Traffic Footprint' metric to quantify environmental impact, urging global collaboration for proactive space sustainability.

The Case for Space Environmentalism

The paper "The Case for Space Environmentalism" provides a comprehensive analysis of the current and anticipated environmental challenges arising from the rapid growth of anthropogenic space object populations, particularly in Low Earth Orbit (LEO). The authors advocate for recognizing the orbital space surrounding the Earth as an essential ecosystem, which necessitates corresponding regulatory frameworks similar to those applied to terrestrial ecosystems such as oceans and the atmosphere.

Key Aspects of Orbital Space

The orbital space, ranging from the Karman line (approximately 80–100 km above the Earth's surface) to Geosynchronous Orbit (roughly 36,000 km), is divided into three regions: Low Earth Orbit (LEO), Medium Earth Orbit (MEO), and Geosynchronous Orbit (GSO). Each region presents unique operational characteristics and challenges:

• LEO (<2,000 km): Characterized by a dense population of satellites and other anthropogenic space objects due to its accessibility and the reduced latency in communications compared to GSO.
• MEO (~20,000 km): Houses systems like GPS and GLONASS, with satellites having longer orbital periods, offering key navigation services.
• GSO (35,786 km): Hosts mainly communication satellites providing services globally, but already faces overcrowding.

The paper highlights the exponential increase in space objects, exacerbated by megaconstellations such as SpaceX's Starlink. The potential future with tens of thousands to possibly over a hundred thousand satellites poses substantial risks of overcrowding and debris creation, threatening the sustainability of space operations.

Environmental Impact

The paper draws explicit parallels between orbital congestion and terrestrial environmental issues, underscoring three problematic features: an incremental yet complex damage pattern, the perception of space as a 'free' resource externalizing actual costs, and the implications this has for global commons management. It argues for space to be incorporated into the environmental frameworks and assessed under laws such as the National Environmental Policy Act (NEPA).

1. Astronomy: The presence of satellites adversely impacts both optical and radio astronomy. The reflective nature and radio emissions of satellites interfere with observations, causing data loss, increased noise, and the risk of missed transient events.
2. Public and Cultural Access: The clutter of satellites can lead to 'fake stars' that obscure the night sky, impacting cultural traditions of stargazing and navigation.
3. Operational Safety: Collision risks with space debris, which grow with increasing satellite populations, are highlighted. Disabling or fatal collisions could render certain orbital 'highways' unusable.
4. Ecological and Atmospheric Impact: The increased launch frequency needed to maintain constellations results in atmospheric pollution, with effects such as CO2 and particulate emissions influencing global warming and atmospheric chemistry.

Recommendations and Implications

The authors propose a holistic approach treating orbital space as an integral part of the human environment. They emphasize the need for stringent regulations and global cooperation to manage the space-environmental footprint. A concept akin to a "Space Traffic Footprint" is introduced, proposing a metric analogous to the Carbon Footprint, to quantify the environmental burden of anthropogenic space activities.

By championing for space to be recognized within environmental policies, the paper advocates for preemptive and collaborative action. Theoretical advancements in orbital traffic management, shared technology standards among space-faring nations, and reducing satellite launches could mitigate these impacts. Future research in AI-driven collision risk assessment and debris tracking could provide valuable tools in addressing the highlighted concerns.

In conclusion, the paper powerfully argues for new paradigms and policies to ensure space remains a sustainable environment, echoing the intricacies and interdependencies found within Earth's own ecosystems.