【美国重启宇航员登月计划：下周阿耳忒弥斯二号准备起飞】
阿耳忒弥斯二号的飞行路线在纸面上看起来杂乱无章，但实际上却是人类迄今为止飞行轨迹最为精准的路线之一。

发射后，猎户座飞船并非直接飞向月球。它先进入一个偏心率较大的地球停泊轨道，然后执行一次精确计时的地月转移轨道注入（TLI），使其进入一条高能自由返回轨道。这条轨道延伸至月球之外很远的地方，绕过月球后急剧弯曲，然后迅速返回地球，而无需进行大规模的发动机点火。

为什么会有如此复杂的环形轨迹？因为猎户座飞船是在多体引力场中飞行。随着它远离地球，月球的引力开始占据主导地位，扭曲了飞船的速度矢量。猎户座飞船相对于其飞行方向会从月球后方经过，从地月系统中“窃取”轨道能量，并自然地改变其返回地球的路径。

这并非简单的椭圆——它是受限三体问题的一种解决方案，在这个问题中，微小的时间变化会产生巨大的几何差异。这条轨道特意穿过引力边界区附近，使猎户座飞船能够在推进力最小的情况下改变方向。

NASA 选择这条环形轨道只有一个原因：安全保障。

即使在地月转移轨道 (TLI) 后推进系统发生重大故障，仅靠引力也能将宇航员送回地球。与此同时，这项任务也使猎户座飞船暴露在深空辐射、远程导航误差、月球距离通信延迟以及以约 11 公里/秒的速度进行双曲线地球再入大气层的环境中——这些条件在地球轨道上是无法模拟的。

阿尔忒弥斯二号的轨道并非高效。它具有容错性，遵循物理规律，并且能够残酷地揭示各种问题。这正是在将人类送上月球之前所需要的。

如果现在终于理解了轨道力学图，请保存此内容。
Artemis II's flightpath looks chaotic on paper-but it's one of the most deliberate trajectories ever flown by humans.

After launch, Orion doesn't head straight to the Moon. It enters an eccentric Earth parking orbit, then executes a precisely timed Trans-Lunar Injection (TLI) that places it on a high-energy free-return trajectory. This path stretches far beyond the Moon, curves sharply around it, and then whips back toward Earth without requiring a major engine burn.

Why the wild loop? Because Orion is flying through a multi-body gravity field. As it moves away from Earth, the Moon's gravity begins to dominate, twisting the spacecraft's velocity vector. Orion passes behind the Moon relative to its direction of travel, stealing orbital energy from the Earth-Moon system and naturally bending its path back home.

This isn't a simple ellipse-it's a solution to the restricted three-body problem, where small timing changes produce massive geometric differences. The trajectory deliberately threads regions near gravitational boundary zones, allowing Orion to reverse direction with minimal propulsion.

NASA chose this looping path for one reason: fail-safety.

Even with a major propulsion failure after TLI, gravity alone returns the crew to Earth. At the same time, the mission exposes Orion to deep-space radiation, long-range navigation errors, lunar-distance comms delays, and a hyperbolic Earth reentry at ~ 11 km/s-conditions impossible to simulate in Earth orbit.

The Artemis II trajectory isn't efficient. It's forgiving, physics-driven, and brutally revealing. That's exactly what you want before sending humans to land on the Moon.

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