Growing a vegetable garden isn't so difficult, on earth. But a space garden… well, that's another story. Still, as Sheri Quinn reports, plants will likely be an important part of future space missions, not only to sustain the travelers' bodies, but their souls, as well.
Plants are a vital part of the earth's eco-system, and they're just as crucial in the artificial environment of an orbiting space station. As on earth, they provide food, and offer a sense of tranquility.
Scientists from the U.S. space agency NASA and Utah State University are working with Russian colleagues to figure out how to grow edible plants in space, and understand their psychological value to space explorers. Bruce Bugbee is a professor of plant physiology at Utah State. His lab helps test so-called space gardens.
"We now are trying to quantify, how important are they?" he explains, adding that he is not just talking about providing fresh greens for the crew's diet. "Are there people that just don't need plants around and if there are, are those the kind of people we want to be flying? Are those the most mentally stable people or are the most mentally stable people the ones that like plants and like interacting with plants?"
In fact, since 2002 the International Space Station has had a small greenhouse garden, called Lada. Named for the ancient Russian goddess of spring, Lada was created to provide green space for the crew during their long flights. It was a collaborative effort by Utah State researchers at the Space Dynamics Lab and scientists from the Institute for Biomedical Problems in Moscow. The suitcase-sized plot has produced a small but steady supply of fresh produce, mainly peas and a type of fast growing lettuce called mizuna. Scientists use Lada to study how plants grow in microgravity.
Space Dynamics Lab engineer Shane Topham says Lada also provides a welcome distraction for crewmembers. "In fact, when the space shuttle a few years ago broke up on re-entry, the crew members who were on the space station were obviously shaken up about that, and one of the things that the Russian space program did to try and calm them down was to assign them more crew time to gardening because they noticed it did have a calming effect. So if they can use that as a psychological tool to help regulate the worry or difficulties psychologically then that's a very good benefit to having plants in space, independent of the food."
Now, researchers are working to quantify those psychological benefits. They plan to track the amount of time crewmembers spend tending the garden. Vladimir Gushin, a psychologist at Russia's Institute for Biomedical Problems, says this kind of study is new and there's not enough data yet to make scientific conclusions.
Gushin says confinement on the space station isn't the problem for the crew, it's a lack of stimuli…things often taken for granted on earth like wind blowing, birds chirping, or seeing a new face. "We have to minimize the cargo on the ship and at the same time keep [the crew] alive physically and mentally." He says green growing plants can make a difference on the ship. "Plants are one of the opportunities that makes them feel something is changing, that nature is with them, a piece of earth is with them… that gives them the feeling that there is still of piece of earth, of life. From this point, nothing can substitute for plants."
The trick is getting the plants to think they are growing on earth with sunlight. In the tiny Lada greenhouse, plants grow upwards towards common household fluorescent bulbs. Instead of soil, they're planted in a bed of baked clay particles. Since excess water won't drain away in micro-gravity, it's meticulously measured and replaced, and air is recycled through filters to remove trace contaminants that are toxic to the plants.
The space garden is helping researchers learn more about air quality and agriculture on earth, but the ultimate goal is to grow food in space for long missions to other planets. In fact, Utah State professor Bruce Bugbee looks forward to a greenhouse on Mars. "I think it's more than possible, I think it's essential," he says. "There's a point at which you can't possibly bring enough food with you…you can imagine an entire trailer full of bag lunches for a four-year trip to Mars. At some point, it's cheaper to bring the whole space farm and solar cells and grow your own food."
The next crop to be planted and harvested in orbit will be the grain, barley. The seeds are going up on the next shuttle mission to the International Space Station later this year.
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在地球上开辟一座菜园并不困难。可是，开辟一座太空园子嘛，那就是另外一回事了。在未来太空任务中，植物很可能会是重要的部分，不只因为它可以供应太空旅程中人类身体的所需，它也是为了人类心灵上的需要。
在地球环境系统中， 植物是极为重要的部分。它们在太空轨道上空间站的人造环境中，也具有同样的重要性。正如它们在地面上一样，它们提供食物和安宁的感受。
对植物重要性加以量化
美国国家航空航天局和犹他州立大学的科学家们，正在和俄罗斯的同行们研究如何在太空栽种可以食用的植物，并且寻求了解，植物对从事太空探索的宇航员来说，在心理上的价值。犹他大学生理学教授布鲁斯.巴格比主持的一个研究室，正协助进行有关太空菜园的试验。
“我们正试行以数量来显示，植物究竟有多重要？真有不需要植物在身旁的人吗？如果有，我们能不能让这种人飞行？这些人是不是属于精神状态稳定的人？或者，绝大部分精神稳定的人是否都是喜欢植物，并且喜欢与植物产生互动的人？”
其实，自从2002年以来，空间站一直有一个名叫拉达的小温室菜园。拉达是古老俄罗斯春天女神的名字。拉达园开辟的目的，是要为漫长飞行中的宇航员，提供一个绿色的空间。这是美国犹他州太空力学研究室和俄罗斯的莫斯科生物医学研究所的科学家们共同努力创建的。这片园地不过像一个行李箱一般大小，但却稳定的长出新鲜作物，主要是豆类和一种成长快速的莴苣。
科学家们利用拉达园，研究植物如何在微小的引力下成长。同时，太空力学研究室的工程师沙恩.托珀姆说，这片小园地也为宇航员提供了很受欢迎的精神调剂效果。
“事实上，几年前当一架航天飞机在返回地球途中解体时，空间站上的宇航员显然都感到震惊。那时，俄罗斯太空计划作出的一件稳定他们情绪的措施，那就是，分配他们多做些整理菜园的工作。因为他们注意到了这类工作确实有平静情绪的作用。”
现在，科学家们在以数量说明这些心理上的好处。他们要计算出宇航员花在照顾这片小园地的时间。俄罗斯生物医学研究所的心理学家古欣说，这是一项新的研究，目前还没有足够的资料来作成科学上的结论。
“对于植物，他们近年来改换了科学研究的方向，同时美国的科学家也在科技上和观察方面，给予我们很多的帮助，这在观念的交流上，是很重要的。”
古欣说，空间站的狭小，对宇航员来说不是问题。问题是缺少精神的鼓舞，这些鼓舞在地球上是随意可得的。例如风吹、鸟鸣、和新认识的面孔。
古欣：“我们必须将舱内的物品减至最少，同时还要让宇航员们保持精神上和身体上的活跃。植物给予他们感受到不同情况的环境。他们会感觉身处在自然当中，在地面的宁静当中。 他们会感觉空间站上仍有地球和其他的生命。在这方面，没有任何东西的功能可以取代植物。”
这项计划的关键在于要让植物感觉它们还是在地面和阳光下生长。在狭小的拉达温室里，植物朝著室内日光灯向上生长。它们并没有长在土壤里，而是附着在一片烘焙过的陶土微粒上。因为在微弱引力下，过多的水分无法流走，必须被小心的测量和更换。空气中对植物有害的微量污染物，必须被过滤。太空菜园还可以帮助研究人员知道更多的有关空气品质和地面农业的问题。
这个计划最终目标是在飞往另一个星球的漫长行程中，在太空种植食物。事实上，犹他州立大学教授巴格比预见将在火星上建立起植物温室。
巴格比：“我想，这件事不仅仅是可能而已。我觉得它是必要的。在那种情况下，你不可能想象在飞往火星的四年行程里，带著满满一卡车的午餐盒。在一般情形下，带著一座太空农场和太阳能电池，来种植你需要的食物，要便宜得多。”
下一步要在空间站轨道上种植的将是大麦。它的种子将于今年较晚时间装载在下一次飞向国际空间站的航天飞机上。
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