PPolySim OS
Biology & Aerospace Pack · Multi-Solver

Launch Vehicle Sizing

Payload & staging. This multi-solver chains 2 solvers into a single guided workflow — run each step in order and carry the result forward.

Workflow steps
  1. rocket-staging
  2. standard-atmosphere
or unlock everything with Pro →
1

Rocket Staging

open full solver →
Rocket StagingLive

Controls

Presets

The rocket equation grows delta-v only with the logarithm of the mass ratio, so a single stage hauling empty tanks all the way up is hopelessly inefficient. Staging drops dead weight along the way: each stage contributes ve·ln(mass ratio), and their sum easily clears the ~9.4 km/s needed for low Earth orbit.

▶ Run in Python

Data Inspector

Δv per stage4.76 km/s
Total Δv9.52 km/s
Reaches LEO?yes

Governing equation

Reading this result: 2 stages at Isp 350s and mass ratio 4 each sum to 9.5 km/s — past the ~9.4 km/s LEO budget, since every stage adds ve·ln(ratio) after dropping dead weight.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

2

Standard Atmosphere

open full solver →
Standard Atmosphere (ISA)Live

Controls

Presets

The International Standard Atmosphere is the reference model all aircraft and instruments are calibrated against. Temperature falls steadily through the troposphere at 6.5 °C/km, then holds constant in the stratosphere above the tropopause. Pressure and density decay roughly exponentially — at airliner altitude the air is only a quarter as dense as at sea level.

▶ Run in Python

Data Inspector

Temperature-50.0 °C
Pressure26.4 kPa
Density0.413 kg/m³
% sea-level ρ34%

Governing equation

Reading this result: Below the 11 km tropopause, temperature falls at 6.5 °C/km — here it is -50 °C and the air holds 34% of sea-level density.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

Need a private, branded version?

We build custom solvers and workflows for labs, firms, agencies, and courses — your parameters, your branding, your data.

Explore Custom Solver Sets →

More in the Biology & Aerospace pack

Frequently asked questions

What is the Launch Vehicle Sizing multi-solver?
Launch Vehicle Sizing is a guided workflow that chains 2 individual PolySim solvers into one end-to-end analysis, piping each result into the next step.
Is it free to use?
Yes. Every step runs entirely in your browser using real numerics — no install, no account, no cloud cost. Custom or private solver packs are available as a paid service.