将以下文本总结成三句话以内，使用英语和第三人称：
学生问：If gravity had fallen out of favor long ago, would space travel still be possible like it is now? Assuming we have had other methods of propulsion.
老师回答：Yes, space travel would still be possible without gravity. Gravity's role is mainly to keep objects on Earth's surface; in space, different propulsion systems could propel spacecraft through using fuel like rocket engines do. Although understanding gravity is important for precise navigation and accurate trajectories, the main principle of moving in space is about escaping Earth's atmosphere and using propulsion to reach desired locations.
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If gravity were not a factor, space travel would still be possible using alternative propulsion systems. Gravity primarily keeps objects on Earth's surface, while in space, propulsion systems like rocket engines enable movement. Understanding gravity is crucial for precise navigation, but the core of space travel involves escaping Earth's atmosphere and utilizing propulsion for desired trajectories.
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