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
69
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 the 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 intriguing 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 investigate 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 Barents 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 de signers 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 pressure per square haft-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/L1eO777K
0
专业英语八级
相关试题推荐
BurialCustomsinAncientEgyptEveryoneburnsfatdifferently.Thesearchfortheperfectdiethasneverbeenmorefrenzied.
______isregardedasthemostmeaningfulintellectualmovementoftheRenaissance.
Intheeighteenthcentury,Japan’sfeudaloverlords,fromtheshoguntothehumblestsamurai,foundthemselvesunderfinancials
InformationSuperhighwayatWorkThechangesinhowwecommunicatemakeitnecessarytochangehowwethinkaboutcommunicati
InformationSuperhighwayatWorkThechangesinhowwecommunicatemakeitnecessarytochangehowwethinkaboutcommunicati
InformationSuperhighwayatWorkThechangesinhowwecommunicatemakeitnecessarytochangehowwethinkaboutcommunicati
Aswellastheproblemsconcernedwithobtaininggoodqualityaudiorecordings,recordingalsoraisesimportanttheoreticalprob
A、Thepublicwasindignant.B、Thepublicwasresigned.C、Thepresidentremainedsilent.D、Thepresidentdecidedtoaskothercou
新加坡报纸说,中国是世界四大文明古国之一,地大物博,拥有茂密的森林、壮丽的山河,如利剑直插云霄的高峰、雄伟壮丽的瀑布、秀丽的湖泊及富有中华文化光辉的名胜古迹,令世界各国人民神往。但是,更重要的是,中国具有五千多年的历史,遗留下无数的历史文物、珍珠宝藏、古迹
谁知就在他准备启程前往美国之前,他遭到一个突然的打击。她用从未用过的语气给他写了一封信。信中她以一种简略的、办理事务式的态度通知他,说自己的财产正处于全面崩溃的边缘,因而从此以后她无法再供给他任何款项了,她还告诉他,他们之间的亲密关系必须结束了……
随机试题
呼吸衰竭的缺氧和二氧化碳潴留主要的发病机制包括
男性,45岁,反复发作性头痛二年,常在秋季发作,发作时表现为右侧眼眶周围严重的钻痛,每次发作持续1~2小时,神经系统检查仅见结膜充血,头颅MRI检查正常。患者最不易鉴别的头痛为
患儿,男,9岁2个月。发作性喘息、胸闷6个月,声高息涌,胸闷膈满,渴喜冷饮,小便黄赤,大便干,舌红苔黄腻,脉象滑数。支气管舒张试验阳性。胸部正侧位x线片:未见明显异常。该患儿的诊断是
当在工程施工过程中发生共同延误时,承担工程拖期责任的原则应采用()。
根据《建筑市场诚信行为信息管理办法》(建市〔2007〕9号)的规定,不良行为记录信息的公布时间为行政处罚决定作出后7日内,公布期限一般为()。
股份有限公司的股利分配,应以各股东持有的()为依据。
试述幼儿园与小学的区别及如何做好二者的衔接工作。
保护作品完整权不属于著作财产权。()
公平理论的提出者是()
设点M(ξ,η,ζ)是椭球面上第一象限中的点,S是该椭球面在点M处的切平面被三个坐标面所截得的三角形的上侧.求点(ξ,η,ζ)使曲面积分为最小,并求此最小值.
最新回复
(
0
)