Youre on the fourth human mission to Mars, and youre told the Odyssey spacecraft designed to take you there will be the smoothest ride youll ever take. It features a newly christened electric propulsion engine which was in the late stages of testing during the first three missions. The mission starts and the spacecraft travels at a crawl, and you wonder if its broken. A week goes by and youre now traveling at more than 400,000 kilometers (250,000 miles) per hour, and your mind is blown as to how fast youre going, how quickly that happened, and that this mission might be more awesome than you thought.