Satellite Maneuver Tracker

How Satellite Maneuvers Are Detected

Every satellite in Earth orbit is tracked using two-line element sets (TLEs) that encode a satellite's orbital parameters: altitude, inclination, eccentricity, mean motion and more, at a specific epoch. When a satellite fires its thrusters, these parameters change.

Orbital Radar's detection engine compares each new element set against its predecessor for every tracked object. When parameters shift beyond natural perturbation thresholds, accounting for atmospheric drag, solar radiation pressure, gravitational harmonics and lunar and solar perturbations, the system flags a probable maneuver. The event is then classified by type, and an estimated delta-V is computed from the change in orbital energy.

Detection typically occurs within hours of publication. Very small maneuvers may fall below detection thresholds, and there is inherent latency between the actual burn and the updated element set. For well-tracked objects with frequent updates, such as the ISS or Starlink satellites, detection is faster.

What Is a Satellite Maneuver?

A satellite maneuver is any deliberate change to a spacecraft's orbit using onboard propulsion. Maneuvers consume propellant, one of the most precious and finite resources on any satellite, so they are only performed when necessary. Common reasons include:

Orbit raising and lowering: adjusting altitude to reach an operational orbit after launch, avoid space debris, or deorbit at end of life. Starlink satellites perform hundreds of orbit raises as they climb from their deployment altitude to their operational shell.

Plane changes: adjusting the orbital inclination or right ascension. These are among the most fuel-expensive maneuvers and indicate significant operational intent. A large plane change on a military satellite may indicate repositioning for a new surveillance target.

Station-keeping: small corrections to maintain a precise orbital slot, particularly for geostationary satellites that must hold a fixed position above the equator.

Collision avoidance: emergency burns to avoid a predicted conjunction with another object. The International Space Station performs multiple avoidance maneuvers per year.

Learn more about orbital mechanics and maneuver types in the Orbital Academy maneuvers track.

Rendezvous & Proximity Operations (RPO)

Rendezvous and Proximity Operations (RPO) involve one satellite deliberately manoeuvring close to another object in orbit. While RPO has legitimate applications, satellite servicing, refuelling and debris removal, it also has significant military and intelligence implications.

Several nations operate satellites that perform RPO. Russia's COSMOS 2542 released a sub-satellite in late 2019, which then manoeuvred close to a US reconnaissance satellite. In 2020 that sub-satellite released a projectile on-orbit, characterised by US Space Command as an anti-satellite weapons test. More recently, COSMOS 2558 has maintained proximity to USA-326, a National Reconnaissance Office imaging satellite.

China's SJ-21 made headlines in January 2022 when it towed a defunct navigation satellite from geostationary orbit to a graveyard orbit, the first publicly observed active debris removal operation by China. SJ-23 has been observed performing proximity approaches to other GEO satellites. The US X-37B spaceplane frequently changes orbit during its multi-year missions.

This tracker monitors all known RPO-capable satellites and flags maneuvers that bring them within range of other high-value objects, a core discipline of space situational awareness. See anti-satellite weapons for historical context, and Kessler syndrome for why close approaches matter.

Understanding Severity Levels

Critical: watchlist objects manoeuvring, or predicted passes under 1 km between strategic objects.

High: cross-border or military encounters under 5 km, large delta-V events, plane changes and deorbit burns.

Elevated: strategic encounters under 10 km, and notable maneuvers by infrequently-manoeuvring objects.

Moderate and low: routine passes between legacy debris and operationally expected constellation traffic.

Data Sources & Methodology

Orbital element data comes from official space-surveillance publications and public catalogues, refreshed continuously; operator and country data is enriched from public satellite databases. For details see the data sources page.

Maneuver detection, classification, severity assessment and delta-V estimation are performed server-side in real time. All thresholds are calibrated to minimise false positives from natural orbital perturbations while catching genuine propulsive maneuvers.