Laser Ablation Debris Deorbit

Laser Ablation System

Laser power 40 kW

Momentum coupling C_m 30 µN/W

Dwell time per pass 25 s

Debris mass 60 kg

Telemetry

Tracking fragment — laser fires each time it crosses apogee.

Perigee altitude

0 km

Apogee altitude

0 km

Δv per pass

0 mm/s

Laser passes fired

Cumulative Δv

0 m/s

Fragments deorbited

How it works

A ground-based pulsed laser illuminates a tumbling fragment for a short window each time it passes overhead. Each pulse vaporizes a thin layer of the surface; the recoiling ablation plume pushes back on the fragment exactly like a tiny rocket exhaust — this is laser ablation propulsion, the mechanism behind proposals such as the "laser broom" and ground-based debris nudging.

Impulse per pass:  Δp = Cm · P · t_dwell
Δv per pass:       Δv = Δp / m   (applied retrograde)
Vis-viva:          v² = μ(2/r − 1/a)
New semi-major axis: a' = −μ / (2·[(v−Δv)²/2 − μ/r])

The beam is aimed opposite the fragment's velocity at the top of its orbit (apogee), so each pass acts like a tiny retrograde rocket burn there. Because the burn point stays the highest point of the orbit, the apogee altitude barely moves while the opposite side of the ellipse — perigee — keeps dropping. Once perigee sinks to roughly 120 km, atmospheric drag takes over within a few more passes and the fragment re-enters and burns up.

Laser power and C_m (the momentum coupling coefficient, a material/fluence property, typically tens of µN per watt for ablation propulsion) set the thrust force F = C_m·P.
Dwell time is how long the tracking system can keep the beam locked on target during one overhead pass.
Debris mass sets how much that impulse actually changes the fragment's velocity — heavier junk needs far more passes.

Real systems (e.g. proposed EOS/DLR ground-laser concepts) use exactly this coupling: kilowatt-class pulsed lasers, ablation impulse coupling of tens of µN/W, and dozens to thousands of passes to deorbit a single small fragment — which is why laser ablation is discussed mainly for centimeter-to-decimeter debris rather than intact satellites.

Earth Debris fragment Ablation laser (fires at apogee)

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