08 / ELECTRIC PROPULSION · OPTIONAL BONUS
Electric Propulsion Lab.
Small thrust. Precise orbits. How a Hall thruster ionizes propellant and accelerates it electrically — plus an optional station-keeping game.
Inside the Hall thruster
PART 1 · HOW IT WORKSComponent notes
OneWeb case study
REAL HARDWAREWhy this matters for a constellation
Predictable orbital geometry and separation matter when hundreds of satellites share a shell. Busek confirms BHT-350 use on OneWeb spacecraft for orbit raising, station keeping, collision avoidance, and deorbit.
- Thrust
- 17 mN
- Discharge power
- 350 W
- Specific impulse
- 1,244 s
Read-only sourced hardware reference, distinct from the ideal experiment above. Discharge power excludes other spacecraft electrical loads; published nominal performance is not a complete throttle map, and this is not OneWeb flight software or an operational maneuver schedule.
Station keeping
PART 2 · OPTIONAL GAME- Points
- 0
- Survived
- 0:00
- Along orbit
- +200 m
- Across orbit
- +40 m
- Severity
- Calm
Why this matters
FIELD NOTESSmall, sustained beats big and late
Real station-keeping thrusters are weak — a OneWeb-class Hall thruster produces about 17 millinewtons, roughly the weight of a paperclip. The trick isn't strength, it's never letting drift build up. Frequent small corrections cost less and keep a satellite far closer to its slot than rare large ones.
Two independent directions
Along-orbit and across-orbit drift come from different physical causes and barely affect each other near a circular orbit, so the game treats them as two separate corrections rather than one combined push.
A simplified game model
The game uses simple acceleration-velocity-position physics for each direction, not full orbital mechanics — see the Transfer Lab and Kepler Explorer tools for the real thing. Thrust in the game is modeled as short pulses for a punchier feel; real electric thrusters like the Hall thruster above actually fire continuously at very low thrust for long durations.