The ability of tardigrades to survive impact shocks in the kilometer per second and gigapascal range was investigated. When rocks impact planetary surfaces, the impact speeds and shock pressures are in the kilometer per second and gigapascal range. This investigation tested whether tardigrades can survive in impacts typical of those that occur naturally in the Solar System. We found that they can survive impacts up to 0.9 km s⁻¹, which is equivalent to 1.14 GPa shock pressure, but cannot survive impacts above this. This is significantly less than the static pressure limit and has implications for tardigrade survival in panspermia models. The potential survival of tardigrades in impacts of terrestrial impact ejecta on the Moon is shown to be impossible for the average lunar impact speed of such ejecta. However, a notable fraction (around 40%) of such ejecta impact at vertical speeds low enough to permit survival. Similarly, martian impact ejecta striking Phobos, for example, at a typical impact speed will not permit viable transfer of tardigrade-like organisms, but if a fraction of such material had a lower impact speed, survival may be possible. We also consider the implications of this for the collection of viable samples by spacecraft transiting the plumes of icy water worlds such as Europa and Enceladus. We have found the limit on survival of shocks to be around 1 GPa, which is instrumental in determining appropriate mission scenarios and collection methods for the acquisition of viable materials.

中文翻译：

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缓步动物在高速撞击中的生存极限——对泛精子症的影响和冰世界排放的羽流样本的收集

研究了缓步动物在每秒千米和千兆帕范围内经受冲击冲击的能力。当岩石撞击行星表面时，撞击速度和冲击压力在千米每秒和千兆帕范围内。这项调查测试了缓步动物是否能够在太阳系中自然发生的那些典型的撞击中存活下来。我们发现它们可以承受高达 0.9 km s ^{−1 的}撞击，相当于 1.14 GPa 的冲击压力，但无法承受高于此压力的冲击。这显着低于静压限制，并且对泛精子症模型中的缓步动物存活有影响。地球撞击抛射物对月球的撞击表明，缓步动物的潜在生存对于这种抛射物的平均月球撞击速度是不可能的。然而，这种喷射物的显着部分（约 40%）以足够低的垂直速度撞击以允许生存。类似地，例如，火星撞击喷出物撞击火卫一，以典型的撞击速度将不允许类似缓步动物的生物进行可行的转移，但如果这种材料的一小部分具有较低的撞击速度，则有可能生存。我们还考虑了这对通过穿越冰冷水世界（如欧罗巴和土卫二）的羽流的航天器收集可行样本的影响。我们发现冲击生存的极限在 1 GPa 左右，这有助于确定合适的任务场景和收集可行材料的方法。