(Picture 1) Kimmo Huosionmaa https://futurism.com/space- train-concept-could-get- humans-to-mars-in-two-days-if- only-it-would-work/ Above this text is the link for the article, what is written about space trains. The space trains are the fictional spacecraft, what may someday travel in our solar system, and they would not ever stop to the planets orbiter. The needed power of the trip, what would take mankind to Mars in two days those spaceships would get from gravity sling for accelerating their speed. In this scenario, the spaceship would send to the solar system by using conventional rockets. And when it would obtain planets like Mars, then the planet’s gravity would increase the speed of that spacecraft. When the spacecraft would turn to the Sun, the gravity field of the Sun would be used to increase the speed, and then the trajectory would target to the Jupiter and Saturn. The good thing of that vehicle is that it would use only the gravity field of the planets to ...