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Turnips, cress and basil could sprout on the moon in 2015 if NASA’s first plan to grow plants on a world other than Earth comes to fruition.
The aim is to find out if the crews of moon bases will be able to grow some of their own greens, a capability that has proved psychologically comforting to research crews isolated in Antarctica and on the International Space Station, NASA says.
Factors that could confound lunar plant growth include the virtual absence of an atmosphere and high levels of solar and cosmic radiation that bombard the moon’s surface. So the space agency is developing a sealed canister with five days’ worth of air, in which seeds can germinate on nutrient-infused filter paper. The idea is that water will be released on touchdown and sunshine will do the rest.
Over five to 10 days, video cameras will record the plants’ sprouting, their rate of growth and their ability to thrive in lunar radiation conditions. Footage will be shared with schools across the US, so that students supplied with their own copies of the canister will be able to compare lunar and terrestrial growth rates, a move that allows NASA to cut costs by crowdsourcing its control experiments.
The 1-kilogram “greenhouse” will be a paid-for stowaway on an uncrewed Google Lunar X-Prize lander mission—most probably the Moon Express mission planned for late 2015.
NASA’s project builds on earlier work by Bernard Foing at the European Space Agency’s research centre in Nordwijk, the Netherlands. Foing and his team demonstrated in 2008 that plants can grow in crushed rock similar in composition to lunar regolith. While anti-contamination rules prevent attempts to grow plants on the exposed lunar surface, ESA’s results mean that local dust could one day be brought indoors and used in moon gardens. He hopes that future missions might even find a way to test that idea.
“Following our successful tests on rock cress and marigolds, it will be interesting if some of these experiments try making use of local regolith as a growth medium,” he says. In the long term, such pilot studies may be crucial to engineering the kind of plant-growth systems and greenhouses that will let moon colonists live off the land.
“This approach to use a scaled greenhouse is a pragmatic first step,” says Foing. “It should open the way to lunar experiments that study the evolution and balance of microbial communities hosted by plants under the moon’s extreme radiation conditions.”
With which of the following subjects is the passage mainly concerned?
Shopping On Line
take into account
draw on
run for
be compatible with
in advance
46.她决心今年再次竞选学生会主席。
47.你能提前为我安排一辆出租车吗?
48.但是这项研究并没有将其他诸如运输和冷藏之类的因素考虑进去。
49.这位飞行员利用想象力和经验完成了这次艰难的飞行。
50.人口增长应该与社会经济的发展相一致。
All the matter, space, and the time there ever has been or ever will be popped into existence 10 to 20 billion years ago.This tiny, supercompressed point—a “Singularity” in the jargon of physicists—was unimaginably hot and packed with energy. It burst forth in a titanic explosion and, expanding and changing ever since, it has become the universe that we—and who knows who else?—call home? If some cosmologists are right, it’s the only universe there ever has been, but there’s no way of knowing for sure.
Great art________moral teaching.
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The heat, which may result from sources such as solar heating or burning of fossil fuels, can be converted into electricity with a very (36) efficiency through a process known as thermionic conversion. Due to the many advantages that would have a system of this type which would be tradable(37) a large scale, many efforts have been for more than half a century to try to develop a practical thermionic generator, with little luck(38)—all attempts. However, such luck may change soon, (39)to a new design: an electronic thermal(40). The thermionic generators used the difference in temperature(41) a hot metal plate and a cold to (42) electricity. Basically, it creates a difference in electrical (43) between the hot plate and the cold. The(44) voltage drives an electric current, (45) the need for movement of mechanical parts.
Evidence has failed to______this assumption.
There is a supermarket_______our house.
Workers were told to______safety regulations in the factory.
He is always_______money before payday.
We should give up smoking______health.
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