What Happens When 36,000 Satellites Share the Same Orbital Highways?
The Sustainability Cost of Mega-Constellations
If there’s one story this week that should stop you in your tracks, it’s this: our growing mega-constellations might be the very thing that makes space unsafe. In this issue, we lead with a remarkable and deeply troubling study by Hugh G. Lewis and Georgia Skelton that drills into what happens when ambition collides with reality. We’ve long talked about the promise of broadband from space and global connectivity, but the numbers don’t lie. With LEO traffic up nearly 50% in just five years, and daily conjunction alerts piling up, even well-managed constellations are staring down an annual collision risk north of 10%!
What’s even more striking when reading this paper is how clearly it exposes the gap between our risk models and our rapidly changing orbital environment. The satellites we used to fear (the old, defunct, drifting kind like the now infamous Kosmos 482) are no longer public enemy number one. It’s the active, operational workhorses that are now at the heart of the problem. And while operators scramble to lower collision thresholds and dodge debris with increasing frequency, we’re burning through both propellant and predictability. This is a reality check for the space sector. We need smarter policies, sharper tools, and a whole new way of thinking about traffic management in space.
Let’s dive in.
In This Issue
Safety considerations for large constellations of satellites
Raiders of the Lost Venus Probe: a post-mortem of an interesting reentry and the confusion it left
Office of Space Commerce Releases Update to TraCSS Beta With On-Demand Screening
Can we protect historical sites on the moon before it's too late?
How to Handle Resource Waste from ISRU on the Moon
Dark Sky Advocates Fight Against a Bright Future
Secure World Foundation 2025 Space Sustainability Research Fellowships
Safety considerations for large constellations of satellites
In their insightful study, Hugh G. Lewis and Georgia Skelton from the University of Southampton tackle the sobering realities of satellite mega-constellations and their rising collision risk. As the number of resident space objects in LEO skyrockets (up nearly 50% in just five years!), the paper dives into the hidden dangers lurking behind those shiny broadband ambitions. Using extensive conjunction data and simulations with the DAMAGE model, the authors reveal that despite thousands of risk mitigation maneuvers, some existing constellations still face more than a 10% chance of collision annually. That’s not just a statistic, it’s a warning flare for the entire space sector.
The analysis isn’t just about what’s happening now, but what might come next. With operators like Starlink and OneWeb contributing to over half of all daily conjunction alerts, the pressure on satellite operators is relentless. Many are already adopting lower collision probability thresholds (sometimes 1-in-100,000) to stay ahead of the game, but this only increases the frequency of costly and risky maneuvers. The study finds that residual risk from low-probability events, usually ignored under traditional thresholds, could still pile up and pose significant threats to the sustainability of space operations.
Simulations modeled a hypothetical 36,000-satellite constellation and projected what might happen in a world full of traffic and ambition. Even with perfect post-mission disposal and zero hardware failures, catastrophic collisions still occurred, sometimes because the risk level fell just under the maneuver threshold. The analysis suggests that user-serving satellites, not failed ones, are now the biggest drivers of risk. With many of these satellites maneuvering multiple times a month, this high tempo introduces its own headaches, notably degrading space situational awareness (SSA) and complicating flight safety protocols.
One of the paper’s most striking conclusions is how our traditional risk frameworks may not be enough anymore. The authors argue that focusing solely on satellite failure rates misses the bigger picture. It’s not just about satellites going dead, it’s about how we handle those still active, moving constantly, and engaging in a daily ballet with thousands of potential collisions. New mapping techniques introduced in the study vividly show just how vulnerable even the most carefully managed constellations can be, making a strong case for new strategies and urgent follow-up research.
As Lewis and Skelton make clear, the tools we’ve relied on may not be enough to handle the traffic jams of tomorrow’s orbital highways. With constellations poised to scale into the tens of thousands, the stakes couldn’t be higher!
Raiders of the Lost Venus Probe: a post-mortem of an interesting reentry and the confusion it left
When a Soviet Venus lander from 1972 unexpectedly reentered Earth’s atmosphere in May 2025, it wasn’t just a relic crashing home, it was a reality check for the space age. The Kosmos 482 Descent Craft, originally meant to touch down on Venus, had been silently orbiting Earth for more than 50 years after a failed mission launch. Built to survive the searing conditions of another planet, it made it through reentry intact enough to stir up headlines, confusion, and plenty of questions. Suddenly, a forgotten piece of Cold War hardware was the center of a modern orbital mystery.
But as media speculation swirled, one thing became clear: predicting reentry is hard. Really hard. Teams from TU Delft, ESA, and the U.S. Department of Defense all ran simulations, trying to pinpoint when and where Kosmos 482 would fall. The best guess? Around 6:40 UTC on May 10, just off Australia’s southern coast. Even with state-of-the-art models, different assumptions about drag, atmosphere, and the spacecraft’s shape led to conflicting trajectories, and a big slice of uncertainty.
That uncertainty only grew when you looked at the tracking data… or lack thereof. The final U.S. military update came six hours before impact. ESA got a radar hit in Germany at 6:04 UTC, but no visual observations followed, likely because the reentry happened over ocean in broad daylight. Then Russia’s Roscosmos claimed it splashed into the Indian Ocean… without offering much detail. For an object that once aimed for Venus, its final moments were oddly undocumented, proving how far we still have to go in orbital tracking.
Kosmos 482’s fiery farewell wasn’t just space trivia! If a 53-year-old spacecraft can reenter with so little warning and so many unknowns, what does that say about the rest of the junk orbiting our planet? This is why better global coordination and transparency in space situational awareness is so necessary.
Office of Space Commerce Releases Update to TraCSS Beta With On-Demand Screening
The U.S. Office of Space Commerce just gave satellite operators a powerful new tool in the orbital toolbox: real-time, on-demand screening for collision threats. In its latest update to the TraCSS beta platform (that’s short for Traffic Coordination System for Space), operators can now upload their satellite trajectories and instantly check for potential collisions in space.
TraCSS is set to eventually replace the legacy Space-Track system by the end of 2025, and this latest feature signals that OSC is serious about making space traffic smarter and safer. Since kicking off beta testing last September, TraCSS has been road-tested by big names like OneWeb, Iridium, Maxar, Planet Labs, and even NOAA. This new screening capability is a leap toward giving operators real-time awareness and the ability to dodge danger before it’s too late.
Can we protect historical sites on the moon before it's too late?
As humans race back to the Moon, there’s a real risk we might trample over our own history. The World Monuments Fund recently added the Moon to its 2025 Watch List, the first time a site not on Earth has made the cut. Why? Because iconic locations like Tranquility Base, where Apollo 11 touched down, are now vulnerable to the very activity that makes space exciting again. Between government missions and the rise of lunar tourism, we’re on a collision course with our own legacy.
Advocates like For All Moonkind are calling for urgent action, pushing for international agreements to protect these extraterrestrial heritage sites before they’re disturbed or lost for good. We could think of it like the Antarctic Treaty, but for the Moon. The big question is: can we explore the Moon’s future without erasing its past? As more boots and bots land on the lunar surface, if we’re not careful, the next giant leap could crush the footprint of the first.
How to Handle Resource Waste from ISRU on the Moon
Lunar mining might sound like science fiction, but it’s quickly becoming mission-critical, and with it comes a problem we haven’t solved yet: what do we do with all the waste? In a new study, researchers Evangelia Gkaravela and Hao Chen from Stevens Institute of Technology dig into the messy reality of in-situ resource utilization (ISRU) on the Moon. Sure, extracting oxygen, water, and metals from lunar soil sounds like a game-changer for space exploration, but every method, from molten regolith electrolysis to soil water extraction, leaves behind a trail of waste products like slag and volatile leftovers. The researchers found that even when you factor in the cost and complications of waste management, ISRU still beats hauling everything from Earth. But there’s a catch: without proper planning, we risk turning the Moon’s pristine landscape, which could be a goldmine for science and radio astronomy, into a junkyard.
Dark Sky Advocates Fight Against a Bright Future
The night sky is getting crowded, and astronomers aren’t staying quiet about it. With over 43,000 satellites expected to orbit Earth by 2032, our once-starry canvas is turning into a streaky mess of artificial light. These satellites don’t just photobomb telescope images, they’re also jamming radio signals, threatening everything from deep space research to our cultural connection with the cosmos.
Groups like the IAU’s Centre for the Protection of the Dark and Quiet Sky are pushing for action: stricter limits on satellite brightness, rules to curb radio interference, and perhaps most critically expanding environmental protections beyond Earth. Some companies like SpaceX are trying to play nice, but others are launching shiny hardware with little regard for the view below. Without firm international rules, the sky we’ve looked up to for millennia could be permanently polluted.
Secure World Foundation 2025 Space Sustainability Research Fellowships
Calling all future space sustainability changemakers! The Secure World Foundation has opened applications for its 2025 Space Sustainability Research Fellowships, and this year’s focus couldn’t be more timely. Whether you’re excited about building a circular space economy or cracking the code on better data-sharing in orbit, SWF wants your brainpower. Fellows will spend four months diving deep into the following topics:
Unpacking the Circular Space Economy
Improving Information Sharing for Space Sustainability
The circular space economy track tackles one of the toughest questions in space sustainability: how do we move from a throwaway culture to one built on repair, reuse, and recycling? Meanwhile, the information-sharing focus looks at how better coordination across nations, companies, and agencies, can keep us from stepping on each other’s orbital toes. If you’ve got fresh ideas and a vision for a cleaner, more collaborative space future, this is your chance. Send your proposal and your résumé by June 9.
Interesting Posts & Videos
Johnny Harris’ video, Space War is Real, Here’s How it Works, paints a striking picture of how space has morphed into the ultimate military playground, and what that means for space sustainability is deeply alarming. With satellites now central to communication, navigation, surveillance, and early warning systems, they’ve become both the backbone of modern military power and high-value targets. Militaries are quietly developing and testing space weapons, from lasers and jammers to kinetic missiles and satellite “grappling hooks.” While most of this tech is shrouded in secrecy or masquerading as debris cleanup, the threat of active space warfare is real, and it’s not only escalating tensions but also raising the risk of catastrophic debris events. The sustainability crisis lies in what’s left behind: when these weapons are used (even in “tests”) they create clouds of space debris that can persist for decades, threatening satellites across all sectors. And it’s not just hypothetical. Russia’s 2021 ASAT test alone generated over 1,500 pieces of trackable debris, some of which still endanger the ISS. The rise of reversible, non-kinetic attacks (like GPS spoofing and satellite hacking) may seem cleaner, but they only delay the inevitable if war escalates. Space is already a battleground, and without serious international cooperation, the race to dominate it could make orbit unsustainable for everyone, militaries, civilians, and scientists alike.
Scott Shambaugh, founder of Leonid Space, is raising red flags about Starlink-30115, a satellite that’s deorbiting years earlier than expected. Designed for a five-year mission, this Starlink v2 mini began falling back to Earth after just one, likely due to a propulsion failure. Even more concerning? It’s not alone. Leonid Space has identified at least 15 other Starlink satellites showing similar behavior. While SpaceX can handle the loss, other satellite operators can’t afford unexpected failures. That’s where Leonid steps in, offering real-time deorbit reports to give operators a clearer picture of their satellite’s future in orbit.
Andrew Wolahan is calling on space professionals to step up for a high-impact role at ESA-ESTEC as the Space Segment Lead for the ADRIOS missions. The role supports two cutting-edge projects: RISE, which will test in-orbit servicing by taking control of an active geostationary satellite, and ClearSpace-1, ESA’s first mission to remove unprepared debris from low Earth orbit by targeting the PROBA-1 spacecraft. If you’re ready to shape the future of space sustainability and in-orbit servicing, this is your chance to join the mission!
Conferences & Webinars
Zero Debris Week- 10-12 June,2025 (Registration Deadline May 14) - ESOC, Darmstadt Germany
Space Debris Training Course 2025: call for applications now open - Apply by June 23, 2025 - ESEC-Galaxia, Belgium
The 7th Summit for Space Sustainability - October 22-23, 2025
Centre de Conférences Pierre Mendès France, Paris
Thanks for reading.
Until next time!