METHODOLOGY

Launch Analysis

Monte Carlo trajectory simulation with wind uncertainty analysis and impact prediction.

01

Overview

The launch simulator performs full 6-DOF trajectory analysis with Monte Carlo uncertainty quantification. It answers the critical question: "Where will my rocket land, given wind uncertainty?"

Method

Monte Carlo

Statistical sampling

Iterations

10-200

Configurable

Output

CEP

50% and 95% radii

Use Case

Use this for flight safety planning, waiver applications, and launch site selection. The CEP (Circular Error Probable) statistics help you define safe recovery zones.
02

Monte Carlo Analysis

Monte Carlo simulation runs N iterations with perturbed wind profiles to quantify landing dispersion. Each iteration applies Gaussian noise to wind speed and direction:

Speed Perturbation
Vwind′=Vwind+N(0,σV)V'_{wind} = V_{wind} + \mathcal{N}(0, \sigma_V)
Direction Perturbation
θwind′=(θwind+N(0,σθ))mod  360°\theta'_{wind} = (\theta_{wind} + \mathcal{N}(0, \sigma_\theta)) \mod 360°
σV\sigma_VWind speed uncertainty (m/s), typically 2.0σθ\sigma_\thetaDirection uncertainty (°), typically 15°

Iteration Count

Use 50-100 iterations for quick analysis, 200+ for final flight predictions. More iterations improve statistical confidence but increase computation time.
03

Wind Profile Modeling

Wind is modeled as a multi-layer profile with altitude-varying speed and direction. The convention is meteorological: "FROM" direction (0° = wind from North, blowing South).

AltitudeSpeedDirectionNotes
Ground (0m)3 m/s270°Surface wind from West
500m8 m/s280°Backing with altitude
1000m12 m/s290°Typical gradient
2000m15 m/s300°Upper winds stronger

Wind between layers is linearly interpolated. Direction uses circular interpolation to handle the 360°/0° wraparound correctly.

04

Impact Predictions

The simulation calculates two impact scenarios:

Nominal

Recovery

With parachute deployment

Ballistic

No Recovery

Worst-case if chutes fail

CEP (Circular Error Probable)

CEP is the radius of a circle centered on the mean impact point that contains a given percentage of landing points:

CEP 50%— Half of landings within this radius
CEP 95%— 95% of landings within this radius

Waiver Applications

For FAA waiver applications, add 20-30% safety margin to CEP 95%. Always check ballistic impact distance for recovery failure scenarios.
05

Recovery Planning

The simulation models dual-deployment recovery with configurable drogue and main parachute parameters:

ParameterDrogueMain
DeploymentAt apogeeAltitude trigger
Typical CD×S0.05-0.2 m²0.5-2.0 m²
Target descent15-25 m/s5-7 m/s
Delay0-2 seconds0-1 seconds

Ballistic Impact

Always check the ballistic impact prediction. This shows where the rocket lands if recovery fails completely. Ensure this is within your authorized flight area.
06

Output Statistics

StatisticDescription
CEP 50%Median landing radius from mean impact
CEP 95%95th percentile landing radius
σ East/NorthStandard deviation in each axis
Mean DistanceAverage distance from launch site
Mean BearingAverage direction to landing zone
Ballistic DistanceImpact distance if recovery fails

Coordinate System

ENU

East-North-Up local

Bearing

0-360°

Clockwise from North

Statistics

Circular

Handles 360° wraparound

SOURCES

References

NASA & Technical Reports

Tools & Calculators

Try the Calculator

Put this methodology into practice with the interactive calculator.

Open Launch Simulator