一种能够在恶劣环境下蜷缩成紧密球体的微小生物，被选为研究对象，以了解生物如何应对太空环境。水熊虫，其名称意为“缓步行者”，因在显微镜下的外观也被称为“水熊”，是一种小型无脊椎动物，以其承受多种压力的能力而闻名，包括干燥和冻结。2021年6月3日，这些水熊虫由SpaceX第22次商业补给任务运送到国际空间站。
A minute creature that is capable of forming a tight ball in difficult conditions has been chosen as an object of study to understand how living creatures cope with space. Tardigrades, whose name means “slow walkers” and which are also called “water bears” owing to their appearance under a microscope, are small invertebrate animals famous for their ability to withstand various forms of stress, including desiccation and freezing. The tardigrades were transported to the International Space Station by SpaceX’s 22nd commercial resupply mission on June 3, 2021.NASA’s mission report described this experiment as one of a series of scientific investigations carried out in the orbiting laboratory.
NASA的任务报告将这一实验描述为在轨道实验室中开展的一系列科学调查之一。该研究被称为Cell Science-04，考察了水熊虫如何应对外太空中的压力因素，以及数代遗传活动的变化。NASA为何使用微小的水熊？这项实验旨在回答一个更广泛的问题：当栖息地的变化影响细胞时，生物体会如何反应？在地球上的实验室中，很难复制这些条件。
Known as Cell Science-04, the study examined how tardigrades respond to stress factors in outer space, as well as changes in genetic activity across several generations. Why did NASA use microscopic water bears? This experiment aimed to answer a broader question: How do organisms react when changes in their habitat affect their cells? It is not easy to replicate these conditions in laboratories on Earth.
通过使用一种已经证明其抗压能力的小型生物，科学家可以研究其韧性背后的机制。NASA的Cell Science-04研究概览将实验的核心目标确定为表征短期和多代生存，并识别参与适应压力环境的基因。该调查使用了Hypsibius exemplaris，这是一种适合实验室研究的水熊虫物种。科学家计划考察其基因表达在暴露于太空飞行条件后如何变化，并将这些变化与在地球上保存的对照样本的结果进行比较。
By using a small organism that has already demonstrated its resistance to stress, scientists can study the mechanisms behind that resilience. NASA’s Cell Science-04 research overview identifies the experiment’s central objectives as characterizing short-term and multigenerational survival and identifying genes involved in adaptation to stressful environments. The investigation used Hypsibius exemplaris, a tardigrade species suited to laboratory research. Scientists planned to examine how its gene expression changed after exposure to spaceflight conditions and compare those changes with results from control samples maintained on Earth.
基因表达是细胞利用基因中编码的信息来制造其活动所需分子的过程。基因表达的变化可以提供关于生物体对压力反应的信息。
Gene expression is the process by which cells use information encoded in genes to make molecules necessary for their activities. Variations in gene expression can provide information about an organism’s response to stress.
研究人员还计划应用RNA干扰——一种用于抑制特定基因的过程——来确定候选基因是否在水熊虫的耐压性中发挥作用。研究人员将动物最初的反应与在太空中长时间停留后观察到的反应进行了比较。在NASA播客采访中，首席研究员托马斯·布斯比解释说，该团队打算研究大约一周后的第一代，以及在太空中维持了大约两个月的另一代，后者代表了大约四代。
Researchers also planned to apply RNA interference, a process used to inhibit specific genes, to determine whether candidate genes played a role in the tardigrades’ stress tolerance. Researchers compared the animals’ initial reactions with those observed after extended periods in space. In a NASA podcast interview, principal investigator Thomas Boothby explained that the team intended to study the first generation after about a week and another generation that had been maintained in space for roughly two months, representing approximately four generations.
科学家能从这项实验中学到什么？生物体对太空飞行的即时反应可能与随时间发展而产生的变化不同。研究连续几代可以让科学家调查这些差异。然而，跨代观察到的变化本身并不能证明某种性状是遗传的，或者后代适应得更好。NASA还在其关于微生物和太空飞行的文章中解释了这项研究对宇航员健康的潜在相关性。
What can scientists learn from the experiment? An organism’s immediate response to spaceflight may differ from changes that develop over time. Studying successive generations allows scientists to investigate these differences. However, changes observed across generations do not, by themselves, prove that a trait is hereditary or that later generations adapt better.NASA also explained the potential relevance of this research to astronaut health in its article on microscopic organisms and spaceflight.
研究水熊虫如何保护自己免受恶劣条件的影响，可能有助于研究人员确定值得调查的生物机制，以保护长期太空任务中的宇航员。然而，这项研究并未确立这些机制可以直接保护人类。潜在应用仍然是研究目标，而非已证实的医疗益处。水熊虫和人类在生物学上存在显著差异，因此帮助微小动物应对压力的机制不能自动应用于宇航员。
Studying how tardigrades protect themselves from harsh conditions could help researchers identify biological mechanisms worth investigating for the protection of astronauts during extended space missions. The research, however, did not establish that these mechanisms could directly protect humans. The potential applications remain research objectives, not proven medical benefits. Tardigrades and humans differ substantially in their biology, so a mechanism that helps a microscopic animal cope with stress cannot automatically be applied to astronauts.
研究人员需要确定哪些过程重要，确定类似机制是否在人类中运作，并测试任何拟议的保护措施。对NASA来说，这项实验是更广泛努力的一部分，旨在了解太空条件如何影响细胞和分子水平的生物系统。
Researchers would need to establish which processes matter, determine whether similar mechanisms operate in humans, and test any proposed protective measures. For NASA, the experiment formed part of a broader effort to understand how space conditions affect living systems at the cellular and molecular levels.
这些知识可能为未来研究提供参考，因为各国航天机构正计划执行让机组人员长期远离地球的任务。了解生物对微重力及其他太空飞行压力的反应，是识别风险并探索降低风险方法的一步。被带到空间站的水熊虫并非仅仅是随货物运输一同前往的生物。它们让科学家得以研究基因表达对太空飞行压力的变化，并考察这些反应在不同代际之间可能存在的差异。
That knowledge could inform future research as space agencies plan missions that keep crews away from Earth for longer periods. Understanding biological responses to microgravity and other spaceflight stresses is one step toward identifying risks and investigating ways to reduce them. The tardigrades taken to the space station were not simply organisms accompanying a cargo delivery. They allowed scientists to study changes in gene expression in response to the stresses of spaceflight and examine how those responses might differ across generations.
细胞科学-04项目旨在提升对水熊虫在太空中的生物过程的认识。这些发现最终能否帮助研究人员开发保护宇航员的方法，目前仍是一个悬而未决的问题。
Cell Science-04 was designed to improve understanding of tardigrades’ biological processes in space. Whether the findings can eventually help researchers develop ways to protect astronauts remains an open question.