Hall Thruster Channel Erosion & Lifetime

Thruster Operating Point

Discharge Voltage 300 V

Propellant Mass Flow 4.0 mg/s

Propellant

Mission Clock Speed 400 h/s

Mission Readouts

Elapsed time

0 h

Peak erosion rate

0 µm/h

Max wall erosion

0.00 mm

Wall remaining

100%

Predicted end-of-life (wall breach)

—

How it works

A Hall thruster ionizes propellant in a crossed E×B field and accelerates ions axially out of an annular ceramic (BN/BN-SiO₂) channel. Some ions strike the channel wall instead of the exit plane, sputtering away ceramic — the dominant wear-out mechanism that ends a thruster's operating life (SPT-100-class units are qualified to roughly 7,000–10,000 hours this way).

The local ion impact energy follows the plasma potential profile, which drops mostly near the exit:

E(u) = V_d · f(u),   f(u) = exp( -((u-0.82)/0.14)² )
u = axial position, 0 (anode) → 1 (exit plane)

Sputtering yield uses a Bohdansky-type threshold law — no erosion below a threshold energy E_th, rising smoothly above it:

Y(E) = Y_max · (1 − E_th/E)²   for E > E_th,  else 0

Local ion current density follows a similar near-exit-peaked profile J(u), scaled by mass flow rate. Erosion depth accumulates as:

dδ/dt = C · Y(E(u)) · J(u)     [wall recession, mm/hour]
End of life: δ_max(u) ≥ wall thickness (3.0 mm)

Discharge Voltage — higher V pushes ion impact energy further above threshold, sharply raising sputtering yield.
Mass Flow Rate — sets ion current density reaching the wall; erosion rate scales roughly linearly with it.
Propellant — Xenon sputters BN more efficiently (lower threshold, higher yield) than the lighter Krypton now used on some mega-constellation thrusters, at the cost of a slightly lower Isp.
Mission Clock Speed — compresses thousands of real operating hours into a watchable session.

This is a simplified engineering model (constants tuned to plausible orders of magnitude, not a specific qualification dataset) meant to show why erosion — not propellant exhaustion — is what typically retires a Hall thruster.

fresh wall → near breach

⚠ Couldn't load the 3D engineThree.js failed to load from the CDN. Check your connection and reload.