This is the master list for equations!

## Δ v

Where:

• M t is total mass.
• M d is total mass minus fuel mass.
• "In" is a natural logarithm.

See the Δ v page for a comprehensive explanation of Δ v.

## Rocket Efficiency

According to Stef:

### Top to Bottom

Where

• E_r is Efficiency of the rocket, and
• M_n < is Mass in tonnes of the succeeding stages.

## Exhaust Velocity of Propellant is the exhaust velocity of your propellant, and is the standard gravity, which on Earth  is: ## Thrust to Weight

• is force of thrust in kilonewtons (kN) and

• is your rocket's mass in metric tons (t). is the force of gravity. For example, on Earth , it is 9.8 m / s 2 .

If the TWR is greater than or equal to 1 your rocket will lift off the ground.

## Average ISP

• is the sum of all the forces, and

• is the fuel consumption rate in kg / s.

Average ISP can also be calculated from each engine:

• is the force in kilonewtons of the n th engine, including duplicates, and

• is the ISP of the n th engine.

## Fuel Consumption Rate

The same fuel flow rate.

## Kepler's Third Law of Planetary Motion

R = Required Δ v for Mission

X = Max Payload in tonnes