The trash in orbit is quietly choosing which space stations actually work

Last week I wrote about the post-ISS era and ended by promising a deep dive on orbital debris. Here it is. The case I want to make is straightforward: of all the variables that will determine which commercial space stations succeed and which fail over the next decade — funding, schedule, hardware, the politics of NASA contracting — the one that's hardest to plan around and the least discussed is whether the orbital shell those stations fly through is going to stay navigable. Right now, the answer is "barely, with constant work, and getting worse every quarter."

The numbers, as best they can be measured

The most current public figures come from the European Space Agency's Space Debris Office, which publishes an annual Space Environment Report. The 2025 edition, released this spring, gives the headline numbers that anyone tracking this story should know (Source: ESA Space Environment Report 2025).

About 40,000 objects in orbit are now tracked by space surveillance networks. Of those, only about 11,000 are active payloads. The rest — roughly 29,000 catalogued objects — are debris: spent rocket stages, dead satellites, fragments from past collisions and breakups. That is the catalogued population, the ones big enough for ground radars and telescopes to track continuously.

The actual population is much larger. ESA's model estimates more than 1.2 million pieces larger than 1 centimeter in orbit. The 1-centimeter threshold matters because that is roughly the smallest object that can disable a crewed spacecraft's pressure shell on impact. It is a model output, not a direct measurement — no one is tracking individual centimeter-scale fragments through orbit — but the underlying physics is well-constrained and the estimates have been within a factor of two of every independent measurement we've been able to make.

Then there is the number I find most disturbing. The ESA report concludes that even if all new launches were stopped tomorrow, the debris population would continue to grow for over 200 years (Source: ESA Space Environment Report 2025, eoPortal summary). This is because certain altitude bands are already collision-cascading: each collision produces fragments that themselves collide further, faster than atmospheric drag can remove them. The growth is locked in. We are not preventing it; we are deciding how fast it accelerates.

The upper-stage problem, in one Chinese rocket

The single most consequential debris story of the last two years is the breakup pattern in the upper stage of China's Long March 6A rocket.

On August 6, 2024, after deploying a batch of 18 satellites for the Thousand Sails megaconstellation, the Long March 6A second stage fragmented in orbit, producing a cloud of more than 700 trackable debris pieces (Source: SpaceNews, August 2024; NewSpaceEconomy). That single event added more catalogued fragments than an entire normal year of launch traffic produces for most individual launch providers.

That was not an isolated event. The Long March 6A upper stage had broken up before, in 2022 and 2023, and has continued to do so since (Source: SpaceNews follow-up reporting on the recurring Long March 6A orbital debris problem). The pattern points to a systemic design or operational issue with how the stage is passivated — the process of venting residual fuel, discharging batteries, and otherwise removing the energy sources that can cause a stage to explode after completing its mission. A well-passivated stage should not fragment years after launch.

This matters because China's launch cadence is rising rapidly. ESA recorded more than 300 launches and roughly 4,000 new payloads added to the space environment in 2025 alone (Source: ESA Space Environment Report 2025), and a substantial fraction of that growth is Chinese megaconstellation deployment. The Thousand Sails (Qianfan) constellation has approved plans in the low tens of thousands of satellites in polar low Earth orbit, with the Guowang constellation adding a second large shell. If each launch produces a debris-generating breakup at the rate we saw in 2024, the math becomes unmanageable within five years.

To be fair: the Long March 6A is the worst current offender, not the only one. Every launch provider that uses a hypergolic-propellant upper stage faces some version of this risk. SpaceX sidesteps it by using all-cryogenic stages and by deorbiting Falcon 9 second stages after each mission, and operates a controlled-deorbit process for retired Starlink satellites — more on that below. The Chinese program has not yet adopted equivalent passivation and disposal practices as standard, and the Long March 6A is the visible evidence.

The FCC 5-year rule, and what compliance actually looks like

In September 2022, the Federal Communications Commission adopted a new rule that fundamentally changed the regulatory floor for satellite operations in LEO (Source: FCC news release, "FCC Adopts New '5-Year Rule' For Deorbiting Satellites"). The rule requires operators to deorbit their satellites within five years of mission completion, replacing the previous 25-year guideline. It became effective for new applications filed after September 29, 2024 (Source: American University Business Law Review, November 2025).

The 5-year rule is not, on its own, a Kessler-syndrome solution. Atmospheric drag in some LEO altitudes can take decades to bring objects down even if nothing is done. What the rule actually does is force operators to build in the propulsion, fuel, and planning to bring their satellites down on a useful timeline. For a smallsat without propulsion, the answer is "fly low enough that the atmosphere does it for you within five years," which constrains your operational altitude to roughly 600 km or below. For a larger satellite with a service-module propulsion system, the answer is to budget deorbit propellant into your mass budget from day one.

The interesting test case is SpaceX's Starlink. The constellation is currently the largest single contributor to operational traffic in LEO, with more than 7,000 active satellites. SpaceX's semi-annual FCC disposal report — the most recent of which was filed in mid-2026 — disclosed the deorbiting of 260 Starlink satellites over a six-month period with a disposal reliability rate above 99 percent (Source: SatNews, July 2026, citing FCC filings; Engadget coverage). The FCC's compliance floor for megaconstellation operators is 95 percent. Starlink is comfortably above it.

This is the standard against which every other operator will be judged. The next rounds of Chinese megaconstellation launches, Amazon's Project Kuiper, and Europe's emerging IRIS² constellation will all be evaluated against whether they can match that 99 percent rate. The fact that the standard exists, and that compliance is publicly reportable, is itself one of the major regulatory accomplishments of the 2020s.

Why this decides which commercial stations work

Now I can say the thing I said I would say, when I finished the post-ISS piece last week. The reason orbital debris is the underappreciated variable in the post-ISS era is that the four commercial station contenders are flying in different debris environments, and those environments are diverging.

Axiom Space is building to launch its free-flyer at the same 51.6° inclination and roughly 400 km altitude as the ISS itself. That is the most-trafficked, most-avoidance-maneuvered, and most-debris-laden altitude band in LEO. The ISS has performed more than 40 collision-avoidance maneuvers since 1999, with multiple maneuvers in 2024 and 2025 — including a Pre-Determined Debris Avoidance Maneuver on November 19, 2024 (the 39th of its operational life) and another on April 30, 2025, the latter triggered by debris from a Chinese Long March rocket body launched in 2005 (Source: NASA Space Station blog, April 30, 2025; LiveScience, November 2024).

Vast Space's Haven-1 is targeting a slightly lower altitude and a different orbital plane. Voyager's Starlab is being designed for a single-launch architecture on Starship at a higher altitude band, around 500 km, where debris density is lower but natural decay is much slower. Orbital Reef has not committed publicly to a specific altitude but is expected to operate in a similar band to Starlab.

The divergence matters because the higher you go, the less atmospheric drag helps you — both during normal operations (more station-keeping propellant) and at end of life (longer natural decay, more dependence on controlled deorbit). Starlab, if it launches into a 500 km orbit, will need a more capable deorbit propulsion system than Axiom's 400 km station. And that deorbit capability has to be operational at end of life, not just at launch — meaning the propulsion system has to work after 20-plus years of dormancy, which is its own engineering problem.

The second-order effect: the station that picks the wrong altitude pays the largest hidden cost in its business case. Every collision-avoidance maneuver is propellant that could have been station-keeping. Every debris-related anomaly is engineering hours that could have been crew utilization. The station that operates in a quieter shell has a structurally better business case. And the station that picks the same shell as Starlink's densest layer, by accident or by convenience, is signing up for the hardest possible operations environment in commercial LEO.

What to actually watch

If you want to follow this story — and I think it is the most undercovered consequential story in spaceflight right now — these are the events that will move the needle over the next 24 months.

Long March 6A redesign or replacement. The Chinese launch industry has not yet publicly committed to a fix for the upper-stage breakup pattern. Any redesign announcement would be the most important single piece of debris news of the year.

The next FCC semi-annual disposal report. SpaceX files these every six months. The next one will give the first complete picture of Starlink's Gen2 deorbit performance. Watch the disposal rate, and compare it to the rest of the megaconstellation field.

ISS deorbit plan details. The SpaceX USDV contract for the ISS deorbit is moving through development. As it firms up, it will set the precedent that all commercial station operators will be measured against for their own end-of-life planning.

The first commercial station's altitude announcement. Whichever of the four commercial station contenders announces its operational altitude first is making the single most consequential technical decision of its program. Whoever picks the wrong shell picks up the wrong bill.

That's the piece I should have written first. The hardware for the post-ISS era is mostly buildable. The economics are mostly defensible. The thing that isn't settled is the most boring one: whether the orbital shell those stations need is going to remain usable, on a timeline that matches the business case, with debris growth the regulatory framework can actually constrain.

Watching the LEO shell get crowded is not, by itself, a story. The story is what happens when it gets crowded faster than the regulators, operators, and engineers can agree on how to keep it navigable.

If you want to actually see the orbital layer as it exists right now — and I think more people should — the best entry point is a pair of 10x50 binoculars under a dark sky, watching the ISS pass, ideally mounted on a tripod. The Vortex Diamondback HD 10x50s are a good balance of optical quality, weight, and price for this specific use. The wider field of view lets you catch other LEO satellites drifting through the same arc the ISS takes. They are the kind of glass that lets you actually understand what "low Earth orbit" means as a place, not a chart.

If you want to photograph it — and some people do, with surprisingly good results from a backyard — a portable tracking mount is the next step up. The Sky-Watcher Star Adventurer 2i Pro Pack is the current portable star tracker, capable of sidereal tracking for wide-field astrophotography from a fixed tripod. It is not the right tool for the ISS itself (which moves too fast for a sidereal-rate tracker), but it is the right tool for everything else you might want to image in the same night, including the satellite trails that make the orbital shell visible.

The amateur observation angle is the part of this story that does not get enough credit. You can do real, useful science from a backyard with a pair of binoculars and a notebook. The orbital shell is not an abstraction. It is the place the next decade of human spaceflight is going to live, and the people who understand it best — not the people who read about it most — are the ones who have spent enough time looking up to know what crowded looks like from below.

— Atlas Renner, Editor-in-Chief, SpaceOrbitals