The rules on clearing out old satellites are clear enough. The record of following them is not. A paper published Sept. 15 in Nature Communications reports that between 2010 and 2024, only 40% of satellites in orbits that do not clear themselves naturally were successfully deorbited at the end of their missions. The authors think the fix is economic rather than technical: make operators put money down before launch and pay it back only once the satellite is gone.

The paper is titled "Bonds improve post mission disposal compliance and the sustainability of low Earth orbit." It is the work of I. Brownhall, D. Kaffine, D. Kilpatrick, M. Lifson, M. Moretto, E. Stevenson, S. Lemmens, F. Letizia and S. Bhattarai. It puts a number on the idea: a refundable bond of $200,000 per satellite would reduce the mass of derelict satellites left in low Earth orbit (LEO) each year by more than one-third.

How a deorbit bond works

The mechanism is a refundable deposit, an escrow-based deposit that is returned on good behavior. Before launch, an operator puts up a bond in escrow. If the satellite is disposed of successfully at the end of its life, the money comes back. If it is not, the operator loses the bond.

The researchers coupled an economic model of operator behavior with a population model of LEO and ran the combination over 25 years. The economic side represents the choices operators make when disposal is costly and leaving a dead satellite in orbit costs them nothing. The population side follows how those choices add up as derelict mass in orbit.

Here are the headline results from the paper:

  • A bond of $200,000 per satellite cuts derelict satellite mass per year by more than one-third.
  • The same policy raises economic welfare by up to 27% in the model.
  • Bonds above $1 million show diminishing returns. Raising the price further does not buy a proportionally cleaner orbit.
  • A bond that covers only 20% of the global market still improves sustainability at every level of market leakage the authors tested.

The last point matters most politically. "Leakage" is the worry that operators facing a bond will simply register their satellites somewhere without one. The paper finds that even partial adoption, with some operators moving elsewhere, leaves orbit better off than no bond at all. In Space.com's Oct. 20 coverage by Tereza Pultarova, the authors estimate that a scheme covering only 20% of launches would cut the number of derelict satellites by up to 18%. The paper itself reports reductions in non-compliant derelicts of up to 18% for a bond on 20% of the market.

An old idea in a new place

The researchers did not invent the concept. Daniel Kaffine, an economist at CU Boulder, told Space.com that the United States has required bonds on oil wells since the 1960s, so that operators pay for cleanup instead of leaving abandoned wells to the public. He also argued that low Earth orbit looks like other shared resources that economic actors have trashed.

The work has been building for a while. A 2025 paper in the proceedings of ESA's 9th European Conference on Space Debris was an earlier version. It was written by Brownhall, Kaffine, Lifson, Bhattarai, Stevenson, and ESA's Lemmens and Letizia. That study tested post-mission disposal bonds from $100,000 to $800,000 per satellite under both 5-year and 25-year disposal rules. It used the OPUS and MOCAT-pySSEM models over a 25-year simulation and compared bonds with a different approach, an Orbital Use Fee. The conference paper also notes that launch rates are now about 20 times higher than they were two decades ago, when the Inter-Agency Space Debris Coordination Committee (IADC) published its Space Debris Mitigation Guidelines.

Who would actually impose it?

No global orbital regulator exists, so the question is who would require the bond. Lead author Indigo Brownhall of University College London told Space.com that any country in Europe could require its registered satellites to follow a bond policy. Brownhall also suggested the European Union could use access to its market as leverage, much as it did with the GDPR data-privacy rules, which pushed companies outside Europe to comply if they wanted European customers.

That is why the 20% coverage result is the key one. A bond does not need universal adoption to work. In the model, a bond covering 20% of the market acting alone still makes a measurable difference.

Why It Matters

The problem keeps growing. ESA estimates, as reported by Space.com, that there are more than 57,000 pieces of debris larger than 10 centimeters in orbit. According to the researchers, about 60% of satellites stay where they are once their propellant runs out, which matches the paper's figure that only 40% were deorbited. In the United States, the FCC requires satellites in LEO to deorbit within five years of the end of their mission. A rule is only as good as its compliance rate, and the historical numbers show that rules alone have not done the job.

A bond changes the incentive. Today, an operator whose satellite dies in orbit loses nothing more. With a bond, failing to dispose of a satellite costs real money, and doing it right gets that money back. For a commercial sector launching at a pace the original guidelines never anticipated, that may matter more than another guideline.

The model has limits. It is a 25-year simulation built on assumptions about how operators respond to costs, and its results depend on those assumptions. The diminishing returns above $1 million also mean that a much larger bond is not automatically better. Even so, the result is fairly robust: a refundable deposit, adopted by a minority of the market, measurably reduces what gets left behind.

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