With this knowledge of orbits, we are ready to plan a trip to Mars. ... The spacecraft will already have the 107,000 kilometers per hour (66,500 miles per hour) speed of Earth, whereas Mars moves at only 86,900 kilometers per hour (53,900 miles per hour). ... A speed of about 42,000 kilometers per hour will be enough to escape the Earth's gravity and, when added to the Earth's orbital speed around the Sun, put the spacecraft on a Hohmann transfer orbit to the Red Planet. ... 1,570,000 . ... Earth . ...