Language Point 1
Someday, in exploring the outer planets of our solar system, humankind will want to do more than send small probes that merely fly rapidly by them. (Para.1)
Meaning: When we explore the outer planets of our solar system in the future, we will want to do more than just send small exploring instruments that just fly past them at high speeds.
probe: n.
1) an instrument for exploring
They have designed a probe which will carry out the mission to explore the Mars. 他们设计出了能够对火星进行勘探的探测器。
2) a searching examination or investigation
The police are working on a probe to find out the causes of the fire. 警方正在对火灾的起因进行调查。
Language Point 2
In time, we will want to dispatch spacecraft that will go into orbit around these alien planets, land robots on their moons, and even return rock and soil samples back to Earth. (Para.1)
Meaning: Sooner or later, we will want to send off spacecraft to orbit these strange planets, have robots landed on the moons of these strange planets, and even send rock and soil samples from these moons back to Earth.
dispatch: v. send off; send away rapidly to a particular place or for particular purpose
If more than one item is ordered, they will be dispatched in separate packages. 如果订购物品在一件以上，将分别包装发送。
The scientific journal Nature dispatched a team, which included university professors, to observe these experiments. 科学杂志《自然》派出了一个包括数名大学教授在内的小组观察这些实验。
Note: The plural and singular forms of "spacecraft" are the same.
alien: a.
1) wholly different in nature or character; strange
The way of life in that area is totally alien to her, who used to live in an old-fashioned way. 她对那个地区的生活方式十分生疏；她以往过着老式的生活。
2) foreign; relating to or belonging to another country
It is easy for children to adjust to an alien culture. 孩子很容易适应外国文化。
Language Point 3
Eventually, we will want to send humans to their moons, on at least a couple of which liquid water — the fundamental requirement for life as we know it — is believed to be abundant. (Para.1)
Meaning: Eventually, we will want to send humans to the outer planets' moons. On at least a couple of the moons, we believe there is plenty of liquid water — and, as we all know, water is the fundamental requirement for life.
Language Point 4
For missions such as these, we will need rockets powered by a nuclear reaction rather than igniting chemicals. (Para.2)
Meaning: For this kind of missions, we will need rockets that are powered by a nuclear reaction but not by burning chemicals.
ignite: vt. set on fire; make burn
The bombs ignited a fire which destroyed some 20 houses. 炸弹爆炸引发的大火烧毁了大约20幢房子。
Language Point 5
But the relatively low amount of energy that they can deliver for a given mass of fuel is a severe drawback when dispatching spacecraft over long distances. (Para.2)
Meaning: But the amount of energy that can be produced by burning a given amount of chemical fuel is relatively low, and this is a major problem in sending spacecraft on missions that cover such long distances.
drawback: n. disadvantage; flaw; anything which hinders progress or success, etc.
Living in a big city has its drawbacks as well as advantages. 居住在大城市里有其优点也有其不足之处。
The only drawback of the plan is that it costs too much. 该计划的惟一缺陷是耗资太多。
Language Point 6
To reach the outer planets, for example, a chemically-powered space vehicle must conserve fuel by having a very small mass and making extensive use of gravity "assists", in which the craft maneuvers close enough to a planet for the planet's gravity to propel the craft forward, boosting its speed. (Para.2)
Meaning: For spacecraft powered by chemical fuel to reach the outer planets, they must be small in size and take advantage of the planets' gravity "assists" for saving fuel. To achieve an "assist", the craft must fly skillfully close enough to a planet and make use of the planet's gravity to push it forward and to speed it up.
conserve: vt. keep from being wasted, damaged or destroyed; preserve
We are a high-consumption society and we must conserve the national resource and make sure that every part of it is effectively used. 我们是一个高消费社会，我们需要保护国家资源并确保资源的每一部分都得到有效地利用。
We should be helping to conserve the environment and discouraging the unnecessary destruction of trees. 我们应该帮助保护环境，劝阻对树木的不必要的毁坏。
maneuver: v.
1) move or turn skillfully
She maneuvered her car into a difficult parking space. 她设法把车开进一个不易停车的地方。
2) get sth. one wants by using a clever or dishonest plan
By secretly buying company shares he maneuvered himself into a controlling position. 他通过秘密地购买公司的股票而得到一个要职。
propel: vt. push or drive forward or onward
The purpose of many such small-scale adaptations is to propel the enterprise forward. 许多小规模调整的目的是推动企业的发展。
His addiction to drugs propelled him into a life of crime. 吸毒成瘾使他走上了犯罪的道路。
Language Point 7
In technical terms, chemical rockets have low maximum velocity growth, which means that their exhaust velocities are not high enough to impart very high speeds to the rocket. (Para.3)
Meaning: Technically speaking, chemical rockets are low in maximum velocity growth, which means that the speed they discharge their exhaust gases is not high enough to create very high speeds for the rocket.
velocity: n. speed that sth. moves at in one direction; rate of motion
At current velocity, the plane will arrive in New York within two hours. 按目前的速度，飞机将于两小时内到达纽约。
Wild winds were sweeping at a rapid velocity throughout the country. 狂风以非常快的速度席卷了这个国家。
impart: vt. give or grant
He will impart that experience to the managers of tomorrow through his continuing involvement in the business. 他将通过对业务工作的继续参与把经验传给未来的经理。
Doctors do not always impart this information clearly to their patients. 医生并不总是把这种情况清楚地告诉病人。
Language Point 8
The best chemical rockets, which are based on the reaction between hydrogen and oxygen, impart a maximum velocity of about 10 kilometers (six miles) a second to spacecraft departing from Earth orbit. (Para.3)
Meaning: The most efficient chemical rockets are based on the reaction between hydrogen and oxygen, and the maximum speed they are able to produce for a spacecraft leaving Earth orbit is about ten kilometers (six miles) a second.
Language Point 9
Nuclear rockets, in contrast to their chemical counterparts, could impart a maximum velocity of up to about 22 kilometers a second. (Para.4)
Meaning: In comparison to chemical rockets, nuclear rockets can attain a maximum speed of about 22 kilometers a second.
counterpart: n. a person or thing that corresponds to or has the same function as sb. or sth. else
The US Congress is the counterpart of the British Parliament. 美国国会相当于英国议会。
The sales director made a phone call to his counterpart in the other firm. 销售经理给另外一个公司的销售经理打了电话。
Language Point 10
Such a high value would make possible a direct path to, say Saturn, reducing travel time from about seven years to as little as three. (Para.4)
Meaning: With such a high velocity, direct flight to Saturn, for instance, is possible, with the traveling time being reduced from about seven years to as short as three years.
Language Point 11
A nuclear rocket such as this would be inherently safe and environmentally harmless: contrary to popular belief, a nuclear rocket need not be strongly radioactive when launched. (Para.4)
Meaning: Contrary to what is commonly believed, a nuclear rocket like this would in essence be safe and harmless to the environment since a nuclear rocket would not be very radioactive at the time it is launched.
radioactive: a. pertaining to or characteristic of radioactivity
Much research has been done on the disposal of radioactive wastes. 在处理辐射性废弃物方面已进行了大量的研究工作。
A radioactive element was discovered in the eighteenth century. 放射性元素是在18世纪发现的。
Language Point 12
The spacecraft, with its nuclear rockets, would be launched on top of a conventional chemical rocket. (Para.4)
Meaning: The spacecraft and its nuclear rockets would be launched into space by being placed on top of a conventional chemical rocket.
Language Point 13
Then, once the vehicle had ascended to high-Earth orbit, above about 800 kilometers, the nuclear reactor module would detach from the chemical rocket and start up. (Para.4)
Meaning: Once the vehicle has risen to an orbit of about 800 kilometers high, the module containing the nuclear reactor would separate from the chemical rocket and switch on and start working.
ascend: vi. go or move upward; rise
We watched the mists ascending from the valley below. 我们看着薄雾从下面的山谷中升上来。
vt. mount; climb
It took about twenty minutes to ascend the mountain for the view, but it was worth the effort.登山观景花去了约20分钟，但这是值得的。
I found a narrow pass before me, and then began to ascend the rough track. 我发现前面有一个很窄的关口，之后就开始沿着艰难的小径向上爬。
detach: vt. unfasten and remove a part from sth.
A gear will be detached from the machine which stopped working. 出了故障的机器上的齿轮将被拆下来。
He has to detach the chain from the bike before fixing the tire. 在修轮胎之前他需要把链条从自行车上拆下来。
Language Point 14
The technology required to build a rocket motor powered by nuclear fuel is not far beyond current capabilities. (Para.5)
Meaning: We have most of the technology that is necessary to build a rocket powered by nuclear fuel.
Language Point 15
In fact, my colleagues and I have designed a compact nuclear rocket engine, which we call Mitee (deriving the letters loosely from the words "miniature reactor engine"), that could be built in about six or seven years at a cost of $600 million to $800 million — actually quite modest in the context of space launches. (Para.5)
Meaning: In fact, my colleagues and I have designed a small nuclear-fueled rocket engine that we call "Mitee"; we got the name from letters in the words "miniature reactor engine". It could be built in six or seven years at a cost of $600 million to $800 million, which is actually quite inexpensive when compared with other space launches.
compact: a. arranged so as to save space
The latest product of the company is a compact camera designed for those who love traveling. 公司的最新产品是为爱好旅游的人而设计的小型照相机。
miniature: a. represented on a small scale; very small
An exhibition of miniature photography will be held in the city museum. 微型摄影展将在城市博物馆举行。
n. portrayal or representation of anything on a small scale
They sell miniatures of the Eiffel Tower to visitors. 他们向参观者出售埃菲尔铁塔的微缩模型。
Language Point 16
In fact, the costs of developing the engine would be offset by savings in future launch costs. (Para.5)
Meaning: In fact, the costs of developing such an engine would be compensated for by the savings on the cost of space launches in the future.
offset: vt. counter-balance; compensate for
The family had to offset the father's small salary by living economically. 全家只得靠节俭过日子来弥补父亲的微薄收入。
The low cost of rail transport will be offset by the high expenses of loading and unloading. 低廉的铁路运输费将被昂贵的装卸费所抵消。
Language Point 17
The reason is that a nuclear spacecraft powered by the engine would not need to haul along a large mass of chemical fuel, meaning that launching it would not require a gigantic rocket costing $250 million to $325 million. (Para.5)
Meaning: The reason for the savings is that a spacecraft with a nuclear engine would not need to carry a large amount of chemical fuel, and this means it would not need to be launched into space by gigantic rocket that costs $250 million to $325 million.
haul: v. pull or draw strongly
With difficulty, she hauled this terrified boy away from the burning house to safety. 她费了很大的劲才把这个受到惊吓的小孩从着火的房子拖到安全的地方。
How long will it take to inflate the bags and haul the plane to the surface? 需要多长时间才能将这些袋子充满气把飞机拉到水面上来？
Language Point 18
Instead, a lower-priced rocket, in the range of $50 million to $125 million, could be used. (Para.5)
Meaning: Instead, a lower-priced rocket that would cost between $50 million and $125 million could be used.
Language Point 19
In our design, the reactor's nuclear fuel would be in a configuration where layers of metallic sheets are penetrated by numerous small holes and then formed into a cylinder. (Para.6)
Meaning: Our design has the nuclear fuel put in a place where layers of metallic sheets are penetrated by many small holes before the sheets are rolled into a cylinder.
configuration: n. the shape or arrangement of the parts of a thing; conformation
A small business computer in its simplest configuration is rather popular due to its competitive price. 由于价格上的优势，配置简单的小型商用计算机非常受欢迎。
Now mankind has got a clear picture of the configuration of the moon's surface. 现在人类对于月球表面的构形有了清楚的了解。
metallic: a. pertaining to or consisting of metal
They are working on a kind of metallic compound, which could be used for aviation purposes. 他们正在试制一种可用于航空的金属化合物。
cylinder: n.
1) the tube within which a piston moves backwards and forwards in an engine or piece of machinery
The machine works on the force coming from a hydraulic cylinder. 这台机器是靠液压缸产生的力工作的。
2) a hollow or solid shape with a circular base and straight sides
The painting was rolled up and put into a cardboard cylinder. 画被卷起来放在一个硬纸板做的圆筒里。
Language Point 20
Liquid hydrogen would flow from the outside of the cylinder inward, through the holes, quickly turning into a gas as it heated up and flowed toward the center. (Para.6)
Meaning: It would work this way: liquid hydrogen entered the cylinder from the outside through the holes in the cylinder's side, and then changed into a gas as it heated up and flowed toward the center.
Language Point 21
The superheated gas, at about 2,700 degrees Celsius, would flow at high velocity along a channel at the center axis of the cylinder and then out through a small opening at the end. (Para.6)
Meaning: Once at about 2,700 degrees Celsius, the extremely hot gas would flow along a channel at the center axis of the cylinder before finally being ejected from its opposite end at a very high speed.
axis: n. an imaginary straight line around which a planet or other round body spins
Long ago, people proved that the Earth rotates on its own axis. 很早以前，人们就证实了地球绕地轴自转。
Language Point 22
A key attraction of nuclear rockets is that the fuel actually propelling the craft — hydrogen — is widely available in gases of the giant planets of the outer solar system and in the water ice of distant moons, planets, and comets. (Para.7)
Meaning: A significant attraction in using nuclear rockets is that the fuel that propels the craft — hydrogen — is abundant in the atmospheres of the giant planets in the outer solar system and in the water ice of distant moons, planets, and comets.
comet: n. a bright celestial body that develops a cloudy tail as it moves in an orbit around the sun
A huge comet is approaching the Earth and will be visible for a few weeks. 一颗巨大的彗星正在接近地球，几周内都可以看到。
Comets move around the sun like planets, but in a long oval course. 彗星像行星一样绕太阳运转，但其轨道呈狭长的椭圆形。
Language Point 23
Thus, because the nuclear fuel would be relatively long lasting, it's possible to envisage a nuclear-powered craft touring the outer solar system for 10 or 15 years, collecting its hydrogen fuel as necessary. (Para.7)
Meaning: Because the nuclear fuel would last a fairly long time, it's possible to imagine a nuclear-powered craft that travels through the outer solar system for 10 or 15 years and collect its hydrogen fuel whenever necessary.
envisage: vt. have a mental picture of
She had never envisaged that they would all be solidly against it. 她从来没有想到他们会这样坚决地反对它。
Our latest project was more costly than we had envisaged. 我们最近的一项工程耗资比我们原先设想的要多。
Language Point 24
A vehicle could fly for months in the atmospheres of the giant gas planets collecting and purifying hydrogen for fuel, while also gathering detailed data on the composition of the atmosphere and weather patterns. (Para.7)
Meaning: A vehicle could fly for months in the atmospheres of giant gas planets by collecting and purifying hydrogen for fuel, while at the same time gathering detailed information about the composition of the atmospheres and weather patterns.
purify: vt. make or become pure, free from impurities
The salt was specially purified for use in medicine. 药用盐是专门提炼过的。
The air in these rooms needs to be purified by filtration. 这些房间内的空气需要通过过滤来净化。
Language Point 25
Alternatively, a craft could fly to one of their moons to collect rock samples and also accumulate hydrogen, by separating water obtained from melted ice, for the trip back to Earth. (Para.7)
Meaning: An alternative would be that a craft could fly to one of their moons and collect rock samples and accumulate hydrogen by means of seperating water that is obtained from melted ice for its trip back to Earth.
Language Point 26
In the outer parts of the solar system, the sun's rays are too feeble to provide energy for spacecraft's instruments. (Para.8)
Meaning: In the outer parts of the solar system, the sun's rays are so weak that they can't provide power for spacecraft's instruments.
feeble: a. lacking in strength or endurance; very weak
Those journalists have criticized his feeble efforts in handling the crises. 那些记者抨击他在处理危机时措施不力。
He was worried by the results, and thought he must be dying to have as feeble a pulse as that.他为诊断结果而感到担忧，认为他会因脉搏虚弱而死去。
Language Point 27
So, they generally run on highly radioactive power sources, which are dangerous even during launch. (Para.8)
Meaning: So, they are generally powered by highly radioactive sources that are dangerous even during launch.
Language Point 28
In a probe with nuclear rockets, on the other hand, the instruments would be run off the same reactor that propels the spacecraft. (Para.8)
Meaning: In a probe that uses nuclear rockets, the instruments would get their power from the same reactor that propels the spacecraft.
Language Point 29
Moreover, the amount of radioactive waste produced would be negligible — amounting to about a gram of highly radioactive material for a deep-space mission — and in any event the material would never come back to contaminate the Earth. (Para.8)
Meaning: Another advantage is that the amount of radioactive waste produced would be so small that it can be neglected — amounting to a gram of highly radioactive material on a deep-space mission — and there is no possibility that the material would come back to pollute the Earth.
negligible: a. not worth considering (because of trifling size, amount, or extent); insignificant
Twenty years ago, when the firm was of negligible size, he became its director and proceeded to build it up into a giant enterprise. 20年前，当公司规模非常小时，他成为该公司的经理，并努力将其建设成为一个大公司。
The world production of iron and steel is somewhere round 450 million tons, and that of all other metals is negligible by comparison. 世界钢铁产量大约是4亿5千万吨，相比之下其他金属的产量就微不足道了。
contaminate: vt. pollute; make impure
It provides a standard method for treating contaminated soils and sands. 它提供了处理被污染的土壤和沙地的标准方法。
Then it happened again and I checked the fuel filter and discovered that it was contaminated.之后同样的情况又出现了；我检查了燃料过滤器，发现它已被污染。
Language Point 30
...the US Space Nuclear Thermal Propulsion Program... (Para.9)
thermal: a. hot; pertaining to or caused by heat
It was proved a long time ago that most metals are thermal conductors. 很久以前就证实大多数金属都是导热体。
A thermal nuclear reactor can be used to generate electricity. 热核反应堆可以用作发电。
Language Point 31
Its goal was to develop a compact, lightweight nuclear engine for defense applications, such as launching heavy satellites into high-Earth orbit. (Para.9)
Meaning: The goal of the program was to develop a small, lightweight nuclear engine for defense purposes, such as launching heavy satellites into high-Earth orbit.
Language Point 32
Although the work ended before a full-scale nuclear engine was built, engineers did successfully fabricate and operate low-power prototype reactors based on the concepts for such an engine and demonstrated that power outputs in the range of millions of watts could be achieved. (Para.9)
Meaning: Although the work ended before a full-scale nuclear engine was built, engineers were successful in making and operating a low-power prototype reactor based on the original ideas for such an engine, and it demonstrated that millions of watts of power could be achieved.
fabricate: vt. make or manufacture; build
The factory has the capacity to fabricate 100,000 cars annually. 该厂年生产能力是100,000辆汽车。
The company is entrusted to fabricate airplane parts. 该公司负责生产飞机部件。
prototype: n. an original model on which subsequent forms are based
The machines will be built on a German prototype. 这些机器将按照德国的原型制造。
They continued working for ten days and succeeded in designing a production prototype. 他们连续工作了10天，最后成功地设计出生产原型。
watt: n. a particular unit of electric power
One unit of horsepower is equal to 746 watts. 1马力等于746瓦特。
Language Point 33
It is an easily provable fact that with only chemical rockets, our ability to explore the outer planets and their moons is hindered. (Para.10)
Meaning: It is easy to prove the fact that when we only use chemical rockets, our ability to explore the outer planets is greatly limited.
hinder: vt. interfere with the progress; retard; prevent from occurring
This kind of research has proved of little value in the past and this will continue to hinder medical progress in the future. 这种研究在过去已证实没有什么价值，而且将继续防碍未来的医学发展。
They can detect the problems which may hinder learning. 他们能够发现可能影响学习的困难。
Language Point 34
In the near term, only nuclear rockets could give us the kind of power needed to allow us to significantly improve our understanding of the still largely mysterious worlds at the far edges of our solar system. (Para.10)
Meaning: For now, we can see that only nuclear rockets could give us the kind of power that is needed to better our understanding of the worlds that are still largely mysterious at the far edges of our solar system.
