Understanding Deorbit
Controlled vs uncontrolled deorbit
There are two ways to bring a satellite down. A controlled deorbit fires one or more retrograde burns to steer the craft to a precise re-entry over open ocean — essential for heavy objects whose surviving debris could otherwise endanger people below. An uncontrolled deorbit simply lets atmospheric drag erode the orbit until the satellite falls somewhere along its ground track, which regulators permit only when the on-ground casualty risk stays under the standard 1-in-10,000 threshold. Small satellites and CubeSats usually clear that bar; large spacecraft rarely do.
| Controlled deorbit | Uncontrolled deorbit | |
|---|---|---|
| Method | Targeted retrograde burn | Natural drag / drag sail |
| Re-entry point | Chosen (e.g. Point Nemo) | Unpredictable |
| Best for | Large satellites, ISS | CubeSats, small satellites |
| Debris risk | Contained over ocean | Spread along ground track |
Deorbit or graveyard? Altitude decides
Whether a satellite is deorbited at all depends on how high it sits. From low Earth orbit, dropping the perigee into the atmosphere costs very little delta-v — around 100 m/s from a few hundred kilometres up, though it rises to several hundred m/s near the top of the band — so re-entry is the cheapest way to dispose of it. From geostationary orbit at about 35,786 km, a full deorbit would need roughly 1,500 m/s, which is prohibitive. Retiring GEO satellites instead spend a mere ~11 m/s climbing into a graveyard orbit a few hundred kilometres above the belt. The rule of thumb: low satellites come down, high satellites go up.
| Orbit band | Disposal method | Approx. delta-v |
|---|---|---|
| LEO (below ~2,000 km) | Deorbit and re-enter | ~100 m/s (low LEO) |
| GEO (~35,786 km) | Raise to graveyard orbit | ~11 m/s |
The 5-year rule and why deadlines tightened
For two decades the international benchmark was the 25-year rule — clear LEO within 25 years of mission end. As mega-constellations and decades of accumulated debris drove the orbital population higher, that pace looked far too slow. In 2022 the US FCC adopted a 5-year rule, effective September 2024, requiring any satellite ending its mission at or below 2,000 km to deorbit within five years; crucially, it binds foreign operators seeking US market access too, not just US licensees. The aim is to slow debris build-up and cut the odds of Kessler syndrome, a runaway cascade of collisions. Related safeguards include end-of-life passivation and, for hardware already stranded, active debris removal.
| Standard | Deadline | Status |
|---|---|---|
| IADC guideline (2002) | 25 years | Voluntary, international |
| FCC rule (2022, effective 2024) | 5 years | Binding on US-market LEO |