Argument: Orbit of Earth around Sun makes speed faster to Mars than Moon
"Manned mission to Mars." On to Mars: "But reaching Mars is a bit easier thanks to Earth's rotation around the sun. As a rocket escapes Earth to reach another object in space, Earth gives it an extra speed because of its 30 km/sec orbital speed. When we try to reach Mars we profit from this effect, but when we reached the moon, we don't."