首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
As every ancient mariner knew, traveling by sail is a simple way to go. Though the winds could be fickle and the boats pokey, th
As every ancient mariner knew, traveling by sail is a simple way to go. Though the winds could be fickle and the boats pokey, th
admin
2011-01-02
24
问题
As every ancient mariner knew, traveling by sail is a simple way to go. Though the winds could be fickle and the boats pokey, the energy source that moved the ship was free, plentiful and renewable. Now tile same technology that conquered the oceans of Earth may conquer the ocean of space.
This week a Russian and American consortium will announce plans for an April launch of the first so-called solar-sail vehicle, a multicasted spacecraft that will use sunlight to push itself along. To a public raised on smoke-and-fire rocketry, the idea of drawing energy straight from space seems fanciful. To the people behind the new ship, however, the technology is not only sensible but inevitable, the easiest way to reinvent the business of cosmic travel. "This allows us to use very little fuel to fly very great distances," says Bud Schurmeier, a former NASA engineer and an adviser to the project. "It’ s an in- triguing concept."
The idea behind solar sailing is simple. Although light is made of massless particles called photons, such ephemeral things exert real pressure, especially when they flow so close a source as the sun. Attach a sail of lightweight Mylar or other material to a spacecraft, set it up in the path of .that outrushing energy, and you ought to be able to move in almost any direction.
NASA has a keen interest in solar sailing and had budgeted $ 5 million to invest igate 17 possible missions. It may select one as early as next month. But while the space agency has been mulling plans, the people behind the new ship, dubbed Cosmos I, have been getting set to fly. The project is the brainchild of Russia’s Babakin Space Center, near Moscow, and the Planetary Society in Pasadena, Calif., a think tank founded in 1979 by astronomer Carl Sagan and others. The two groups had long been developing plans for a solar-sail mission but got the cash to make it happen only last year when Ann Druyan, Sagan’s widow and head of the Media Company Cosmos Studios, and Joe Firmage, the founder of US Web, threw their names and about $ 4 million behind the effort. "I had talked to people about solar sailing before, "says Lou Friedman, former engineer at the Jet Propulsion Laboratory in Pasadena and director of the Planetary Society," but between the Russians’ capabilities and Ann’s vision, I knew this one would click."
The spacecraft is a 3-ft. metal with eight 35-ft. metallic wings. Mylar petals sprout from it -- though the prototype used in the April launch will have just two petals. Mounted atop a reconfigured Russian ICBM and launched from a sub in the B arents Sea, the Cosmos I will fly to an altitude of 260 miles, where it will deploy the wings and float for a minute of so. If all goes well, the wings will then be jettisoned and the sphere aerobraked back to Earth, its bounce-down on Russian soil cushioned by air bags.
By some measures, this cosmic lob shot is not that impressive, but for solar-sail scientists, the engineering is everything. Few doubt that when sunlight strikes the wings, the spacecraft will accelerate; the key is building wings that can open and pivot, allowing the ship to tack into the solar stream. If this mission works, a more ambitious orbital flight, using the eight-paneled craft, is set for the end of the year. The space-craft could circle Earth for months, surfing the sun until designers shut it down. "There will be a grandeur to it, "says Druyan, "a 70-ft. sail that will be visible to the whole planet."
Grandeur aside, critics wonder if solar sails have a future. The technique is problematic in Earth orbit, since the changing position of sun relative to the space-craft makes constant tacking necessary. Sailing is best used for as the crow- flies shots to neighboring planets. Even in these cases, progress can be slow, since sunlight exerts, at most, 2 lbs. of pres- sure per square half-mile, requiring a year or more to rev a spacecraft to interplanetary speeds. Worse, beyond Jupiter, sunlight flickers out almost entirely; to go any farther would require energy beamen from Earth orbit, perhaps by giant laser howitzers. "None of these things has been tested, "says Mel Monte-merlo, one of NASA’s solar-sailing chiefs. "We have a long way to go."
Whether that will continue to seem such a long way may depend on the spring-time flight of Cosmos I. A successful mission has a way of making impossible technologies seem possible -- a big burden for a small rocket that will, for one day at least, carry the hopes of the world’ s space community.
What can be inferred from the passage?
选项
A、Most scientists are confident that the spacecraft will work well.
B、A more ambitious orbital flight will follow this mission.
C、The author is quite sure that this mission will make impossible technologies seem possible.
D、The key of the engineering of Cosmos I is building wings that can open and pivot.
答案
D
解析
该题问:从本文中可以得出什么结论? A项意为“大部分科学家都相信宇宙飞船会运行得很好”,从本文的倒数第二段可以看出此项不正确。B项意为“一个更为有抱负的轨道飞行器将会从事这个特别任务”,本文没有提及。C项意为“作者相信这个任务会使得不可能的目标显得有些希望”,本文中提到的是A successful mission has a way of making impossible technologies seem possible,因此C项中mission前必须加上successful,此项才正确,因此C项不可取。D项意为“宇宙1号操作的关键是能否造出在太空中可以打开的翅膀,而且这些翅膀还能够旋转”。这在第六段中可以找到出处the key is building wings that can open and pivot。因此D项为正确选项。
转载请注明原文地址:https://kaotiyun.com/show/5ZlO777K
0
专业英语八级
相关试题推荐
Cooperationistheonlysafeguardwehaveagainstthedevelopmentofneurotictendencies.Itisthereforeveryimportantthatch
Late-nightcomedianshadafielddayinthesummerof2002whenalawsuitaccusingMcDonald’sofmakingtwoteenagecustomersin
CommunicatingThroughInternetThehistoryoftheInternetcanbedatedbacktothe1960’s,whentheDepartmentof【1】______
A、websetB、educationalschoolC、InternetportalD、foreigncompanyC
Onedayyouwentshoppingwithyourclosefriendinasupermarket.Atapointoftime,younoticedyourfriendwasstealthilypu
将近九十年以后,毛姆在一次广播讲话里用自己的话重申了这个看法,并作了发挥。如果我没有理解错的话,毛姆先生说的是:人的头脑的基本构造之中具有一种东西,它非常喜欢甚至要求听人讲故事,讲一个开头、中间、结尾都齐全的故事。他还说,现代有些作家过分热衷于剖析心理和进
Writeacommentofabout400wordsonthefollowingtopic:1.TheDifferencesbetweenHumanBeingsandAnim
近年来,由于就业问题日益严重,有些人建议让没有工作的未婚妇女来替换那些家务繁重的女工。有些当丈夫的还说:“让我们的爱人回家去,把她们的工资拿来贴补我们。我们从家务琐事中解放出来,工作就能干得更好。”有些有工作的母亲力图一面搞好家务,一面做好工作。她们也附和
但那时我年少,血旺气盛,誓与凡俗抗争到底,于是连哄带骗将一净高1.74米女孩拐回家做起于太大,这一壮举颇为“残废”们扬了一段眉吐了半口气。将太太置回家中后我才意识到我的悲哀,这一愤世之举不仅未了我“终生残废”之恨而又平添了“终生遗憾”,我从未亭受过
随机试题
某二元混合物,若液相组成xA为0.45,相应的泡点温度为t1;气相组成yA为0.45,相应的露点温度为t2,则()。
关于国际商法,下列说法不正确的是()
先天愚型患儿的临床表现,错误的是
血性胸腔积液常见于下列哪项除外
患者男性,18岁,自幼有出血倾向,出血时间延长,凝血时间正常,血小板150×109/L,血小板黏附率降低,部分凝血活酶时间延长,凝血酶原时间正常。父亲也有类似病史,考虑的诊断是
持票人甲将一张银行汇票上记载的金额由10万元改为40万元,甲的行为属于变造票据行为。()
下列()不属于影响教师教育机智的因素。
陕西省着力打造()产业成为陕西的一座“生态金矿”。
树根:根雕
由商品的价格变动所引起的商品相对价格的变动,进而由商品的相对价格变动所引起的商品需求量的变动,称为:
最新回复
(
0
)