#explainer
Ground tracking systems measure object orbits and predict hazardous close approaches. Operators can plan a small manoeuvre for a controllable satellite to alter encounter timing or position. This is generally not a last-second camera-guided dodge.
Predictions contain uncertainty
Position and velocity are not known perfectly. Teams assess uncertainty and collision probability as well as the predicted separation. New measurements update the estimate. An alert does not mean collision is certain, nor does every possible manoeuvre improve the situation.
What manoeuvres cannot solve
Very small fragments cannot all be tracked reliably. Designs therefore also use small-particle protection, while operators limit new debris. An uncontrolled satellite cannot manoeuvre itself. Long-term safety requires tracking, coordination, appropriate design and responsible end-of-life disposal.
Why a small early change can suffice
Avoidance does not require an aircraft-like sharp turn. A small orbital change made early gradually shifts the position or timing of passage through the hazardous region. Late decisions reduce that advantage. Manoeuvres also consume resources and can affect observations, so operators assess both collision risk and the consequences of the change.
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Key points
- Position and velocity are not known perfectly.
- Very small fragments cannot all be tracked reliably.
- Avoidance does not require an aircraft-like sharp turn.
Sources & further reading
- Debris tracking, close approaches and end-of-life disposal.
- Passivation, disposal and orbital collision prevention.
Spaceflightpedia. (n.d.). How do satellites avoid collisions?. Retrieved 17 October 2026, from https://spaceflightpedia.com/article/satellite-collision-avoidance
article text — CC-BY-SA · ◉ NASA photography — public domain · ✦ AI illustration — marked, generated from sources
