A humid bathroom is the perfect habitat for mold. But there are ways to avoid it. "We can just open the window and let some fresh air in!" Not so easy on a space station though, as astrobiologist Petra Schwendner of the University of Edinburgh explains.

潮湿的浴室是霉菌完美的栖息地。但是有方法可以避免霉菌滋生。“只要打开窗户，让新鲜空气进来！”爱丁堡大学的天体生物学家佩特拉.史温德内尔解释道，可是,在空间站这么做可不太容易。

"It has been seen on the international space station or on the MIR that these microorganisms can accumulate. I’ve seen pictures where you could see this corrosion¹ caused by bacteria or an accumulation of fungus² behind wet towels."

“在国际空间站或和平号上，就可以看到这些微生物聚集在那里。我看到过一些图片，在图片上你能看到细菌引起的腐蚀或真菌堆积在湿毛巾后面。”

So as we set our sights on Mars, what might grow in the spacecraft³—essentially a human-scale petri dish—during the year-and-a-half-long flight?

所以，当我们把目光转移到火星，在长达一年半的飞行过程中，宇宙飞船中——基本上是人类大小的培养皿里——会生长些什么呢？

The Mars500 habitat in Moscow simulated that trip, with six crew members confined inside. And Schwendner and her team tested microbial samples of the habitat over time. They found what you might expect: a lot of human-related bacteria and fungi⁴, mostly at levels deemed safe for life in space. But they also noticed a decline in microbial diversity over time—which could indicate a less-than-healthy microbial community that’s potentially more prone⁵ to takeover by hostile bacteria.

火星500在莫斯科的实验基地模拟了这一旅程，居住舱中有6名机组人员。史温德内尔和团队测试了居住舱中的细菌样本随时间推移所发生的变化。他们的发现和人们的预期相一致：在太空中，许多与人类有关的细菌和真菌，大多被认为处于对生命无危险的水平。但是他们也注意到，随着时间的推移，微生物的多样性在减少，这表明不太健康的微生物群落可能更易被敌对细菌接管。

"Seeing this decrease is for us an important point or proof that continuous monitoring is an important fact and is really required for being able to maintain a healthy environment." The study is in the journal Microbiome. “

对我们来说，见证微生物多样性的减少非常重要，它证明了持续监测是重要事实，也是维护健康环境所必需的。”这项研究结果发表在《微生物学》期刊上。

When we do rocket to the Red Planet, it’ll be impossible to keep our spacecraft completely sterile⁶. Humans are leaky animals. The real question might be how we’ll keep our many microbes…from colonizing⁷ Mars.

我们向火星发射火箭时，保持宇宙飞船完全无菌是不可能的。人类不是“密闭”的。真正的问题或许在于，我们如何防止与人类相关的多种微生物殖民火星。