What Is a Controlled Re-entry? Spacecraft Disposal Explained

📘 Definition

A controlled re-entry uses onboard propulsion to perform a targeted deorbit burn, lowering the perigee into the atmosphere along a calculated trajectory that ensures surviving fragments land in a designated ocean area. The preferred target is the South Pacific Ocean Uninhabited Area (SPOUA), centred near Point Nemo — the most remote point on Earth, over 2,700 km from any inhabited land. This is in contrast to uncontrolled re-entries, where defunct objects decay naturally and re-enter at unpredictable locations, posing a small but non-zero risk to populated areas. The ISS, Tiangong-1, and large rocket stages from missions by SpaceX and others undergo controlled re-entry at end of life.

SPOUA (Point Nemo)

Target Zone

48°52'S, 123°23'W

Point Nemo Location

263+ deorbited spacecraft

Objects at Point Nemo

2030–2031

ISS Planned Deorbit

Understanding Controlled Re-entry

Controlled vs Uncontrolled

A controlled re-entry is always preferred for objects large enough that significant fragments survive atmospheric heating. Operators fire thrusters to lower the orbit and steer the ground track over open ocean. An uncontrolled re-entry occurs when a defunct object has no remaining propulsion — its orbit decays due to atmospheric drag and it enters at a time and place that cannot be precisely predicted until the final hours. Notable uncontrolled re-entries include Chinese Long March 5B core stages, which have drawn international criticism for their unpredictable return paths over populated areas.

What Survives Re-entry?

Most spacecraft material burns up during re-entry due to extreme aerodynamic heating (temperatures exceeding 1,600°C). However, components made from titanium, stainless steel, and carbon fibre can survive to reach the surface. The casualty expectation metric estimates the probability of debris striking a person — current guidelines require this to be below 1 in 10,000 for each re-entry event. Learn more about what happens in our guide on what happens when satellites re-enter.

Frequently Asked Questions

What is Point Nemo? ▼

Point Nemo (officially the Oceanic Pole of Inaccessibility) is the point in the ocean farthest from any land — over 2,700 km from the nearest inhabited island. It is the preferred target for controlled re-entries because the risk to human life and property is essentially zero. Over 263 spacecraft have been intentionally deorbited to this area since 1971.

Will the ISS have a controlled re-entry? ▼

Yes. NASA has contracted SpaceX to build a dedicated deorbit vehicle for the ISS, planned for approximately 2030–2031. The station's 420-tonne mass makes it the largest object ever to undergo controlled re-entry — the deorbit vehicle must be powerful enough to steer all surviving fragments into the SPOUA target zone.