Platform
How much a launcher puts into orbit from a given site, found by trajectory optimisation rather than read off a curve: a 3-D flight simulation from lift-off to final orbit, guidance optimised up to direct optimal control, parking orbits and restarts, the site's own upper-air winds, Monte-Carlo dispersions and where every stage falls. The same engine feeds the multi-site Launch Site Study, so every site is compared on a payload actually flown.
Launch performance
The ascent engine behind the study uses the methods of the reference trajectory tools: a 3-D simulation from lift-off to final orbit, direct optimal control in the discrete-parameter formulation of NASA's POST, solved by sequential quadratic programming, multi-burn missions flown with finite burns, upper-air winds and Monte-Carlo dispersions. Every payload it gives is a mission the simulator actually flew, and every method is recomputed live against public reference cases.
Ascent tab · six numbered steps, from the vehicle to the validation on public cases
3-D point mass on a rotating Earth with J2, J3 and J4 gravity and the US 1976 atmosphere. Mach-dependent drag, strap-on boosters with tabulated thrust, fairing jettisoned on heat flux, hold-down until thrust exceeds weight, ignition delays and burn limits, max-Q and max-g throttling down to a minimum throttle, last-stage reserve and required burn margin. Circular, elliptical and GTO targets.
The payload is a decision variable, maximised over the kick angle, the heading, the thrust elevation and yaw at nodes along the upper-stage burns and the cut-off time, under the injection constraints. KKT steps, damped BFGS, active-set bounds, merit and filter acceptance, second-order correction, feasibility restoration and several starting points. A gravity turn and an offset optimiser run alongside; the better result is kept, and the row says which.
Direct ascent, or a parking orbit and a restart: a coast to the equatorial crossing for a GTO, to the perigee for a circular orbit, or for a set time, then the transfer burn and the circularisation. Ignitions allowed, propellant per restart and longest coast are vehicle limits. An optional upper-stage deorbit burn is taken off the payload. Optimal control covers these missions too, with the later burns flown as finite burns.
Each site's wind profile on 12 pressure levels up to 24 km, from a full year of hourly data: annual mean, a month's mean or a month's strong wind (95th percentile) for the loads. The vehicle takes the wind as incidence; q·α is reported for every result and can be limited, with optional normal-force and incidence-drag coefficients. Jettisoned bodies fall in the same wind.
Monte-Carlo on thrust, Isp, masses, propellant load, drag, air density, kick, heading and the fallen bodies' Cd·A: success rate, orbit statistics and an impact ellipse per jettisoned body, with its share on land. Expected casualties per flight against the 10-4 public collective-risk reference of FAA 14 CFR 450.101. Drops at sea a chosen distance from any coast are enforced by steering the trajectory itself.
Planes below the site latitude solved by the better of a dogleg and an in-orbit plane change. Batch runs over sites × targets × vehicles with a payload matrix and CSV export, several sites computed in parallel. Calibration of a vehicle on one published payload, velocity-loss breakdown and C3, JSON export of every run, and trajectories imported from any other tool screened the same way.
Vehicle data and mission profile · stages, limits, fairing, boosters, parking orbit and restart
Results · one row per site, the method kept and why, ignitions, coasts and deorbit
Event console, altitude, speed, dynamic pressure, acceleration and throttle charts, and the drop point of every jettisoned body on the map.
Result detail · headline figures and the ascent charts, or the whole mission
Any chart enlarged, with the value under the cursor
Event console · every event with its time, altitude, speed and mass
Any result replays on a globe you can turn around: the vehicle and its stages, each separation and jettison, the fall of every jettisoned body to its impact point, and the parking, reached and disposal orbits, with a live readout and a jump list of the events.
A whole launch in 3-D, from lift-off to the orbit reached · a real screen recording of SatView, nothing staged: every frame is drawn from the trajectory the application computed from the vehicle, mission, guidance and site parameters
Lift-off above the launch site
Parking orbit, restart and the orbit reached
The ascent, the stage 1 and fairing impacts, and the disposal orbit
Dispersions · success rate, orbit statistics and a 99 % impact ellipse per jettisoned body
The impact ellipses on the map, at sea off the coast
Payload matrix · one column per vehicle, the best site in green, a click opens the flight
| Case | Published | SatView | Gap |
|---|---|---|---|
| Multiple-stage ascent benchmark, Delta III class (Betts 2010, Benson 2005, GPOPS-II), solved by SatView's SQP | 7 529.7 kg final mass | 7 537.7 kg, final time 927 s (≈ 924 s) | +0.11 % |
| Ariane 5G to GTO, published attitude programme | 6 640 kg (user manual) | 6 887 kg with 20 s of EPS margin; main stage out at 585 s (589 s), max Q at 66 s (69 s) | +3.7 % |
| Ariane 5G to GTO, guidance found by the optimiser alone | 6 883 kg (published programme) | 6 961 kg to 200 × 35 786 km, i 7.00° | +1.1 % |
| Europa III Δv budget | Published budget | Reproduced | Exact |
| Ariane 5 ECB project | Chronology, GTO with ≥ 20 s Vinci margin | Chronology and requirement met | — |
| Launch windows: Sentinel-2A from Kourou, Landsat 9 from Vandenberg | Flown at 01:52 and 18:12 UTC | 01:58 and 18:25 UTC | 6 and 13 min |
Ariane 5 and Europa cases from the published exercises of mecaspa.cannes-aero-patrimoine.net. The first five cases run from the Validation frame of the Ascent tab, so anyone can check them.
Validation frame · the published cases recomputed live, with the gaps
Run it on your own vehicle and your own candidate sites, then carry the figures into a full launch-site comparison and its PDF study.
Tell us about your mission — we will get back to you.