以二体问题为模型，从地球发射航天器探索火星，途中需经过一次无动力金星借力，寻找最优（总速度增量最小）的发射时间窗口和飞行时间，并绘制地球到金星的Pork-Chop发射能量等高线图。发射时间窗口为2023—2033年，总飞行时间不得大于2年。(Taking the two body problem as the model to explore Mars from the earth, it is necessary to seek an unpowered Venus transit force on the way to find the optimal time window and time of flight (the minimum total velocity increment), and draw the contour map of the Pork-Chop emission energy of the earth to Venus. The total launch time window is from 2023 to 2033, and the total flight time is not more than 2 years.)