Plot the orbit, size the burn, catch the window.
Orbital speed, period, escape velocity, Hohmann transfers, the rocket equation and planetary launch windows, worked with the same formulas a flight dynamics engineer starts from. Every calculation runs in your browser.
Orbital Velocity Calculator
Find the speed of a satellite in a circular or elliptical orbit around Earth, the Moon, Mars, Venus or Jupiter from its periapsis and apoapsis altitudes, using the vis-viva equation.
Open the calculator 35,786 kmOrbital Period Calculator
Work out how long one orbit takes at a given altitude, or the altitude needed for a chosen period, such as the 35,786 km of a geostationary orbit, using Kepler’s third law.
Open the calculator 11.180 km/sEscape Velocity Calculator
Calculate the speed needed to escape the gravity of Earth, the Moon, Mars, Venus or Jupiter from the surface or from any altitude, and the extra Δv required from a circular orbit.
Open the calculator Δv 3.854 km/sHohmann Transfer Calculator
Calculate the two burns, the total Δv and the transfer time to move between two circular orbits with a Hohmann transfer, from low Earth orbit to geostationary orbit or anywhere else.
Open the calculator 6,118 m/sRocket Equation Calculator
Use the Tsiolkovsky rocket equation to find the Δv of a rocket stage from its specific impulse and wet and dry masses, or the propellant needed to reach a target Δv.
Open the calculator 779.9 daysSynodic Period & Launch Window Calculator
Find how often launch windows open between two planets, the Hohmann transfer time and the phase angle the target planet must be at when you depart, for Earth to Mars, Venus, Jupiter and more.
Open the calculatorResults are ideal two-body figures with instantaneous burns, for study and general interest. They are not mission analysis and must not be used to operate a spacecraft or to fly a rocket.