# How much less delta-v would it take to reach the Sun using Venus and Earth flyby's compared to direct? Tags: orbital-mechanics, physics, mathematics, flyby - Score: 3 - Views: 1217 - Answers: 1 - Answered: yes - Asked by: user12102 - Asked: 2019-09-07 - Site: space ## Question @TomSpilker showed that the minimum delta-v to go from Earth orbit into the Sun is about 20.89 km/s. That's going from 200 km LEO to "perihelion at the sun's photosphere (guaranteed complete entry!)" starting from Earth's aphelion (lowest orbital velocity). But that's with a direct ellipse, not using Venus or Earth flybys. Is it possible to estimate, perhaps by looking at Parker Solar Probe's several flyby's and its delta-v budget how much less it would take to reach the Sun's photosphere cleverly using flybys of Venus and Earth? ## Answers ### Answer by SE - stop firing the good guys (score: 4) The potential of fly-by ping pong is pretty much unlimited, provided you have enough time to your disposal. Given an initial transfer with a perihelion slightly lower than the orbit of Venus, a Venus flyby can increase the aphelion to a bit further out than the Earth's orbit. On the following Earth flyby,