Understanding how spacecraft alter planetary environments can offer important insights into key physical processes, as well as being critical to planning mission operations and observations. In this context, it is important to recognize that almost any powered lunar landing will be an active volatile release experiment, due to the release of exhaust gases during descent. This presents both an opportunity to study the interaction of volatiles with the lunar surface and a need to predict how nonindigenous gases are dispersed, and how long they persist in the lunar environment. This work investigates these questions through numerical simulations of the transport of water vapor during a nominal lunar landing and for two lunar days afterward. Simulation results indicate that the water vapor component of spacecraft exhaust is globally redistributed, with a significant amount reaching permanently shadowed regions (cold traps) near the closest pole, where temperatures are sufficiently low that volatiles may remain stable over geological timescales. Exospheric evolution and surface deposition patterns are highly sensitive to desorption activation energy, providing a means to constrain this critical parameter through landed or orbital measurements during future missions. Contamination of cold traps by exhaust gases is likely to scale with exhaust mass and proximity of the landing site to the poles. Exhaust propagation is perhaps the most widespread and long‐lived impact of spacecraft operations on a nominally airless solar system body and should be a key consideration in mission planning and in interpreting measurements made by landed lunar missions, particularly at near‐polar regions.

中文翻译：

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航天器产生的月球外逸层的演变

了解航天器如何改变行星环境可以提供对关键物理过程的重要见解，以及对规划任务操作和观测至关重要。在这种情况下，重要的是要认识到几乎任何动力登月都将是一个主动的挥发物释放实验，因为在下降过程中会释放废气。这既提供了研究挥发物与月球表面相互作用的机会，也需要预测非本土气体是如何分散的，以及它们在月球环境中的持续时间。这项工作通过对标称登月期间和之后两个月球日的水蒸气传输的数值模拟来研究这些问题。模拟结果表明，航天器尾气中的水汽成分在全球范围内重新分布，大量到达最近极点附近的永久阴影区域（冷阱），那里的温度足够低，挥发物可能在地质时间尺度上保持稳定。外层演化和表面沉积模式对解吸活化能高度敏感，提供了一种在未来任务期间通过着陆或轨道测量来限制这一关键参数的方法。废气对冷阱的污染可能与废气质量和着陆点与两极的接近程度成比例。排气传播可能是航天器运行对名义上无空气的太阳系天体最广泛和最持久的影响，并且应该是任务规划和解释登月任务进行的测量的关键考虑因素，特别是在近极地地区。