02 / ROCKET PROPULSION
Thrust Lab.
Mass flow and exhaust velocity produce the force that moves a rocket.
Live gauges
- Thrust
- 0.0 kN
- Acceleration
- 0.00 m/s²
- Velocity rest frame
- 0.00 m/s
- Total mass
- 20,000 kg 3,000 dry · 17,000 propellant
- Elapsed
- 00:00.0
- Position
- 0.0 m
- Mass flow
- 150.0 kg/s
- Exhaust velocity
- 2,000 m/s
Propulsion
Locked at kN. Feasible range shown on each slider.
Thrust = mass flow × exhaust velocity.
Engine
Propellant exhausted. Reset to refuel.
Engine off, coasting. Settings saved for restart.
Before you ignite
FIELD NOTESMass flow, exhaust velocity and thrust
Thrust equals mass flow times exhaust velocity: F = q·ve. The same thrust can come from a small fast exhaust stream or a large slow one — lock the thrust gauge and move either slider to compare.
Why acceleration climbs during a burn
Thrust stays constant while the lock is engaged, but the rocket's mass keeps dropping as propellant burns. The same force divided by a shrinking mass means acceleration increases as the tank empties.
Cutoff is not stopping
Cutting the engine stops consuming propellant and sets thrust to zero, but in this ideal vacuum model nothing slows the rocket down. It coasts at whatever velocity it had at cutoff until you restart the engine.