📡 Rocket Ascent Flight Simulator — Gravity Turn & Max-Q

Fly a two-dimensional point-mass ascent: set mass, thrust, burn time, drag and a pitch-over programme, then read apogee, downrange, max-Q, max Mach and max g from a live trajectory plot.

Example vehicles
Constant average thrust and a constant Cd. The pitch angle starts at vertical and turns downrange at your chosen rate after the pitch-over altitude.
Apogee——
Downrange at impact——
Max dynamic pressure——
Max Mach——
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Trajectory: altitude above the launch site against downrange distance. The marker is apogee; the dashed segment is powered flight.

Flight telemetry

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    What the simulator integrates, how the pitch programme works, and what it cannot tell you

    The point-mass model. The rocket is a point with variable mass. Thrust acts along the body axis, drag opposes the velocity vector, and gravity points down with a 1/r² variation. Mass falls linearly as propellant is consumed — ṁ = propellant mass ÷ burn time — and stays at the dry mass after burnout. The equations of motion are integrated in two dimensions at a 0.01 s step. Air density and the speed of sound come from a standard-atmosphere approximation, so Mach number and dynamic pressure vary with altitude.

    The pitch programme. The vehicle climbs vertically until the pitch-over altitude, then rotates downrange at the entered rate until it reaches 85° from vertical. A real gravity turn is not a fixed rate: the vehicle follows the velocity vector after an initial kick, and aerodynamic forces help the turn. This simulator lets you explore the effect of an earlier or later pitch-over and a faster or slower turn without pretending to be a guidance algorithm.

    Reading the outputs. Max-Q is the highest dynamic pressure, ½ρV², and usually occurs during the transonic climb; it is the load that sizes the airframe and the point where real vehicles throttle down. Max Mach is the highest speed relative to the local speed of sound. Max g is the largest proper acceleration — thrust plus drag divided by mass — not the felt acceleration from gravity alone. Downrange is where the trajectory returns to the launch-site altitude, not where a parachute would drift.

    Limits. Constant average thrust ignores the thrust curve, and a constant Cd ignores the transonic drag rise and Mach-dependent centre of pressure. There is no wind, no rail tip-off, no staging, no thrust-vector control, no structural flexibility, no rotating Earth and no orbital mechanics. Above roughly 50 km the standard-atmosphere approximation loses accuracy; treat high-altitude apogees as indicative. A trajectory that does not reach orbit here is not evidence that a real vehicle could — orbital insertion needs a completely different guidance and energy budget.

    Why it is still useful. The interactions between thrust-to-weight, pitch-over altitude, burn time and drag are the ones that dominate the shape of a suborbital flight. Changing one input and watching apogee and max-Q move is a fast way to build intuition before reaching for a six-degree-of-freedom simulator.

    Last reviewed: 2026-10-19. A teaching and concept-design simulator, not a flight-planning or range-safety tool.