Imagine a piece of space debris the size of a hockey puck slams into a Starlink satellite at about 10 kilometres per second. The kinetic energy is equivalent to two kilograms of TNT, or a fully-loaded semi-truck travelling at 100 kilometres an hour. The Starlink satellite sprays out dozens of new debris pieces into an expanding cloud. Other satellites will pass by the new debris within minutes — some will need to manoeuvre to avoid yet another collision. As corporations around the world continue to fill low-Earth orbit with megaconstellations, such collisions are increasingly likely. We have developed something called the CRASH Clock to measure this. It asks a simple question: if all satellites in orbit suddenly lost the ability to manoeuvre and control their orientation, how long would it take for two to come close enough to crash? In 2018, before megaconstellations began launching, the CRASH Clock value was 164 days. It has been steadily dropping since then. Our new research finds that as of May 2026, it is at 2.5 days.

The human presence in outer space is undergoing a transition from one in which nation states are the dominant actors to an emerging status quo in which states merely supervise the activities of private entities. Such largely commercial ventures include extracting natural materials from the Moon, a celestial body of great cultural and spiritual reverence for some Indigenous societies. However, the existing international legal framework governing activities in space focuses on its "exploration and use", centered in a Western worldview that attaches to a past history of colonialism. While that framework, articulated in the Outer Space Treaty (OST), claims to guarantee that outer space will remain "the province of all [hu]mankind," only entities with significant political power have to date decided the limits of the acceptable uses of space. This paper examines the historical record for clues about how states, private actors and Indigenous societies might interact in the future on matters of outer space governance to achieve more just ends. It analyzes a key case study: the dispute between the NASA and the Diné people of the American Southwest over the launches of human cremated remains to the Moon in 1998 and 2024, acts the Diné president called "deeply disturbing and unacceptable to our people and many other tribal nations." In a future in which space becomes increasingly commercialized and entities like NASA transform into mere contract-administering agencies, it is unclear how an impending, exploitative human presence on the Moon can simultaneously honor Indigenous rights and perspectives on lunar issues. The presentation concludes that best practices for future engagement with the Moon must transcend the mere "due regard" and "international consultations" required by the OST in favor of arrangements where participants co-create a human future in outer space.

The rapid growth of human activities in outer space sounds urgent alarms around ethical and philosophical issues, particularly concerning space militarization. The present international legal framework governing activities in space, the Outer Space Treaty (OST), views the peaceful exploration of space for scientific research as co-equal to other ‘uses’ entitled to “due regard” with respect to “potentially harmful interference” on the part of other space actors. The OST is deeply aspirational but has weak enforcement mechanisms, relying at its core on the goodwill of all involved parties as the fundamental basis for accountability. But that framework now faces unsustainable pressures from both public and private interests, and current agreements like the OST may be unable to exert timely, material protections. Terrestrial frameworks of "ethics of deterrence" versus the "ethics of agreements” are quickly expanding into cosmic environments. We argue for the legal recognition of space as an environment as the basis of any future approach to securing its integrity, and share examples of agreements grounded in peaceful cooperative stewardship of shared environments. These represent potential pathways forward that are ethical and also serve rational self-interest and self-preservation at this crucial juncture for humanity.

More than 10,000 Starlink satellites currently orbit the Earth. We see them crawling across dark skies, no matter how remote our location, and streaking through images from research telescopes. SpaceX recently announced that it wants to launch one million more of these satellites as orbital data centres for AI computing power. A few years ago, we wrote a paper predicting what the night sky would look like with 65,000 satellites from four planned megaconstellations: SpaceX’s Starlink, Amazon’s Kuiper (now Leo), the U.K.’s OneWeb and China’s Guowang. We calibrated our models to observations of real Starlink satellites and came up with a startling prediction: One in 15 visible points in the night sky would be a satellite, not a star. A million satellites would be so much worse.

The commercial space industry is launching more satellites into Low Earth Orbit every year. Aotearoa New Zealand (NZ) has a thriving dairy and cattle industry. Unfortunately, these industries could come into (high speed) cow-llision, as the rapid launch rate and short operational lifetimes of satellites in megaconstellations like Starlink result in a high reentry rate at NZ's latitudes. This could intersect with NZ's famously large population of livestock. We predict this will be an udder disaster for any cows that are hit, as they are squishy and moo-ve much more slowly than space debris. Using a global bovine density dataset, previously published satellite casualty probability code, and a complete lack of funding to do this calculation carefully enough for submission to a peer-reviewed journal, we calculate a ≃ 0.3-1% chance of a cow-sualty in NZ from reentering Starlink Gen2 debris over the next 5 years.

When we look up at the night sky and see a satellite glide past, we might not consider climate change or the ozone layer. Space may feel separate from the environmental systems that sustain life on Earth. But increasingly, the way we build, launch and dispose of satellites is starting to change that. Over the past few years, the number of satellite launches has skyrocketed. There are now nearly 15,000 active satellites in orbit around the Earth, most of them part of “mega-constellations” in which each satellite has a service life of only a few years. New satellites must be quickly launched as replacements. To avoid leaving old, dead satellites in Earth’s already-crowded low orbits, most satellite operators deliberately de-orbit them into Earth’s upper atmosphere. Here, they burn up or break apart into smaller pieces: a process known as “demisability”. In effect, satellites have become part of throwaway culture. That approach is now being taken to a vastly larger scale. We are concerned about the implications for Earth’s climate and atmosphere.

On January 30 2026, SpaceX filed an application with the US Federal Communications Commission for a megaconstellation of up to one million satellites to power data centres in space. The proposal envisions satellites operating between 500 and 2,000 kilometres in low Earth orbit. Some of the orbits are designed for near-constant exposure to sunlight. The public can currently submit comments on this proposal. SpaceX’s filing is just the latest among exponentially growing satellite megaconstellation proposals. Such satellites operate with a single purpose and have short replacement life cycles of about five years. As of February 2026, approximately 14,000 active satellites are in orbit. An additional 1.23 million proposed satellite projects are in various stages of development. The approval process for these satellites focuses almost entirely on the limited technical info companies have to submit to regulators. Cultural, spiritual, and most environmental impacts aren’t taken into account – but they should be.

The dawning of the Space Age marked the start of an ongoing relationship between the professional astronomical community and both state and non-state actors that launch and operate spacecraft in near-Earth orbital space. While the Cold War heated up in the late 1950s, military uses of outer space quickly came into conflict with the priorities of astronomers then building ever-bigger ground-based telescopes and envisioning the first generation of space telescopes. As the threat of global thermonuclear war loomed, the United States carried out Project West Ford, which tested an “artificial ionosphere” for microwave radio propagation by placing several hundred million tiny copper dipoles into a belt orbiting the Earth. While the test was ultimately successful, it ignited a firestorm of concern and criticism among astronomers and ultimately influenced the framing of the United Nations Outer Space Treaty. Here we examine the history of Project West Ford as it prompted astronomers to react, comparing it with the ongoing problem of the potential impact of large satellite constellations on astronomical research.

The rising population of artificial satellites and associated debris in low-altitude orbits is increasing the overall brightness of the night sky, threatening ground-based astronomy as well as a diversity of stakeholders and ecosystems reliant on dark skies. We present calculations of the potentially large rise in global sky brightness from space objects in low Earth orbit, including qualitative and quantitative assessments of how professional astronomy may be affected. Debris proliferation is of special concern: we calculate that all log-decades in debris size contribute approximately the same amount of night sky radiance, so debris-generating events are expected to lead to a rapid rise in night sky brightness along with serious collision risks for satellites from centimetre-sized objects. This increase in low-Earth-orbit traffic will lead to loss of astronomical data and diminish opportunities for ground-based discoveries as faint astrophysical signals become increasingly lost in the noise. Lastly, we discuss the broader consequences of brighter skies for a range of sky constituencies, equity/inclusion and accessibility for Earth- and space-based science, and cultural sky traditions. Space and dark skies represent an intangible heritage that deserves intentional preservation and safeguarding for future generations.

Our planet and our species are at an existential crossroads. In the long term, climate change threatens to upend life as we know it, while the ongoing COVID-19 pandemic revealed that the world is unprepared and ill-equipped to handle acute shocks to its many systems. These shocks exacerbate the inequities and challenges already present prior to COVID. As weary nations look toward a post-COVID world, we draw attention to both the injustice and many impacts of the quiet occupation of outer space near the Earth, which has rapidly escalated during this time of global crisis. The communities most impacted by climate change, the ongoing pandemic, and systemic racism are those whose voices are missing as stakeholders both on the ground and in space. We argue that significant domestic and international changes to the use of near-Earth space are urgently needed to preserve access to, and the future utility of, the valuable natural resources of space and our shared skies. After examining the failure of the United States and international space policy status quo to address these issues, we make specific recommendations in support of safer and more equitable uses of near-Earth space.

The population of artificial satellites and space debris orbiting the Earth imposes non-negligible constraints on both space operations and ground-based optical and radio astronomy. The ongoing deployment of several satellite ‘mega-constellations’ in the 2020s represents an additional threat that raises significant concerns. The expected severity of its unwanted consequences is still under study, including radio interference and information loss by satellite streaks appearing in science images. In this Letter, we report a new skyglow effect produced by space objects: increased night sky brightness caused by sunlight reflected and scattered by that large set of orbiting bodies whose direct radiance is a diffuse component when observed with the naked eye or with low angular resolution photometric instruments. According to our preliminary estimates, the zenith luminance of this additional light pollution source may have already reached ∼20 μcd m−2, which amounts to an approximately 10 per cent increase over the brightness of the night sky determined by natural sources of light. This is the critical limit adopted in 1979 by the International Astronomical Union for the light pollution level not to be exceeded at the sites of astronomical observatories.