One of the most important equations you will encounter in rocketry is Konstantin Tsiolkovsky's “Rocket Equation”; given below.

Δv = Ve * ln(Mb / Me)

Equation Explained

• Δv = Final Velocity (Delta-vee) of the rocket in meters per second.

• Ve: Velocity of the rocket's exhaust in meters per second.

• Mb: Total mass of the rocket fully loaded (with payload, propellant, etc) in kilograms.

• Me: Empty mass of the rocket at burnout with all propellant expended in kilograms.

Converting ISP into m/sec:

Unfortunately, most rocket engine performance levels are given in ISP, not in exhaust velocity. You can however convert ISP into exhaust velocity with the following equation:

Ev = ISP * 9.81

Equation Explained

• Ev = Exhaust Velocity of the engine in meters per second.

• ISP = Specific Impulse of the engine.