雅思阅读真题（Part 2）
把一颗小行星拖回地球轨道
本篇也叫：小行星捕获计划、抓小行星、小行星拖回地球、小行星采矿、近地小行星、小行星变空间站
Part 2 · 考频：高频 · 最近考试：2021.11.20
本篇为雅思阅读真题（Part 2）《The plan to bring an asteroid to earth》，共 13 题，2021.11.20雅思考试真题回忆，页面提供完整原文、题目、答案与解析，并支持在线机考模式免费练习。本页同时提供 Markdown 版本 供 AI 助手与搜索引擎直接读取。
文章讲的是加州理工学院的科学家提出一项计划：用机器人捕获一颗近地小行星，把它拖到地球轨道附近，作为未来载人深空任务的中转基地。小行星引力弱，便于开采金属并建造太空栖息地，还能缩短宇航员飞行时间。文中还提到NASA行星防御项目及近地小行星数量等背景。
Moving in orbit around our Sun are millions of rocks known as asteroids.
Now scientists have plans to capture one.
A
Send a robot into space, catch an asteroid and bring it back to Earth's orbit. This, say scientists and engineers at the California Institute of Technology (Caltech), could be feasible. A four-day workshop was dedicated to investigating the feasibility of capturing a near-Earth asteroid, bringing it closer to our planet and using it as a base for future manned space-flight missions.
This is not something the scientists are imagining could be done someday in the future. It is possible with the technology we have today and could be accomplished within a decade. A robotic probe could anchor to an asteroid with simple magnets or grab it with specialised claws. Alternatively, a large spacecraft could use its gravitational field to shift the orbit of a larger asteroid, sending it towards Earth.
'Once you get over the initial reaction - You want to do what?! - it actually starts to seem like a reasonable idea,' says engineer John Brophy, who helped organise the workshop. In fact, many of these ideas have been on the drawing board for years as part of NASA's planetary-defence programme against large space-based objects that might threaten Earth. And there's no shortage of potential targets: NASA estimates there are 19 500 asteroids at least 100 metres wide within 45 million kilometres of Earth.
B
Though rearranging the heavens may seem an excessive undertaking, this US mission has its merits. The US already has plans to send astronauts to a near-Earth asteroid, a mission that would mean confining them in a tiny capsule for three to six months and would involve all the risks of a deep-space voyage. Instead, robots could bring an asteroid close enough for them to get there in just a month.
An asteroid would provide a stationary base from which to launch missions further into space. There are several advantages to this. For one, launching missions carrying materials from Earth requires a lot of power, fuel and, consequently, money, because of our planet's strong force of gravity. Since this would be far weaker on an asteroid, materials mined there could be more easily taken off the asteroid and shuttled around the solar system.
Many asteroids have a lot to offer. Some are rich in metals, which can be mined and used to build space-based habitats, or brought back to Earth. Others are up to one-quarter water, which could be used for life-support or broken down into hydrogen and oxygen to make fuel. Astronomers would also have the chance to get a close-up look at one of the solar system's earliest relics, generating important scientific data. 'Executing the asteroid-retrieval plan would help demonstrate and greatly expand mankind's space-based engineering capabilities,' says engineer Louis Friedman, another co-organiser of the Caltech workshop. For instance, the mission would teach engineers how to capture an unco-operative target, which could be useful practice for planetary-defence missions in the event of a threat from a meteoroid or comet approaching our planet, he adds.
C
Former astronaut Rusty Schweickart, co-founder of the B612 Foundation, an organisation dedicated to protecting Earth from asteroid strikes, points out that although it would be technically feasible, shifting such a hefty and substantial target would not be easy: 'You're moving the largest mother-lode imaginable,' he says.
Engineers would need to be absolutely certain they could control such a potentially dangerous object. 'It's the opposite of planetary defence; if you do something wrong you have a Tunguska event,' says engineer Marco Tantardini from the Planetary Society, referring to the powerful 1908 explosion above a remote Russian region thought to have been caused by a meteoroid or comet.
D
Still, these obstacles only add to the appeal of the project for engineers, who love to go over every potential difficulty in order to solve it. And if the challenges posed by a large asteroid seem too daunting, researchers could always start with a smaller asteroid, perhaps two to ten metres across. Last year, Brophy helped conduct a study to look at the feasibility of bringing a two-metre, 1 000-kilogram asteroid - of which there might conceivably be millions - to the International Space Station. The study suggested the asteroid could be captured robotically in something as simple as a large bag. Of course, such a small object might not have the same emotional impact as a larger target. 'NASA isn't going to want to go to something that is smaller than our spaceships,' says engineer Dan Mazanek from NASA's Langley Research Center.
E
No matter the size of the asteroid, these plans would require hefty investments. Even capturing a small asteroid would consume at least a billion dollars. Convincing taxpayers to foot such a bill could be difficult. However, private industry might be interested in getting involved. One possibility would be to push the asteroid into near-Earth orbit and then invite anyone who wants to develop the capabilities to reach and mine the object.
However, although the undertaking might be scientifically exciting and provide great insight into the solar system's formation, this is not enough on its own to justify the expense of bringing an asteroid to Earth. Investigations of asteroids can be done much more cheaply with an unmanned spacecraft, says chemist Joseph A. Nuth from NASA's Goddard Space Flight Center. According to Brophy, ultimately we would be working towards bringing an asteroid closer to Earth in order to help humanity move out into the solar system.
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答案：an achievable goal, not an impossible dream
原文定位：This is not something the scientists are imagining could be done someday in the future. It is possible with the technology we have today and could be accomplished within a decade
答案：practical, economic and research justifications
原文定位：Instead, robots could bring an asteroid close enough for them to get there in just a month.、materials mined there could be more easily taken off the asteroid and shuttled around the solar system;Astronomers would also have the chance to get a close-up look at one of the solar system's earliest relics, generating important scientific data
答案：the need for skill and care
原文定位：Engineers would need to be absolutely certain they could control such a potentially dangerous object
答案：beginning with a less challenging task
原文定位：And if the challenges posed by a large asteroid seem too daunting, researchers could always start with a smaller asteroid, perhaps two to ten metres across
答案：obtaining support for the project
原文定位：Convincing taxpayers to foot such a bill could be difficult. However, private industry might be interested in getting involved
答案：E The skill gained could save Earth from future danger.
原文定位：For instance, the mission would teach engineers how to capture an unco-operative target, which could be useful practice for planetary-defence missions in the event of a threat from a meteoroid or comet approaching our planet, he adds
答案：D An asteroid's weight makes the project extremely challenging.
原文定位：Former astronaut Rusty Schweickart;points out that although it would be technically feasible, shifting such a hefty and substantial target would not be easy;'You're moving the largest mother-lode imaginable,' he says
答案：B It might be difficult to arouse interest in an asteroid of limited size.
原文定位：Of course, such a small object might not have the same emotional impact as a larger target. 'NASA isn't going to want to go to something that is smaller than our spaceships,' says engineer Dan Mazanek from NASA's Langley Research Center
答案：G Capturing an asteroid would not be an efficient method of research.
原文定位：However, although the undertaking might be scientifically exciting and provide great insight into the solar system's formation, this is not enough on its own to justify the expense of bringing an asteroid to Earth. Investigations of asteroids can be done much more cheaply with an unmanned spacecraft, says chemist Joseph A. Nuth
答案：base
原文定位：An asteroid would provide a stationary base from which to launch missions further into space
答案：gravity
原文定位：For one, launching missions carrying materials from Earth requires a lot of power, fuel and, consequently, money, because of our planet's strong force of gravity. Since this would be far weaker on an asteroid, materials mined there could be more easily taken off the asteroid and shuttled around the solar system
答案：metals
原文定位：Some are rich in metals, which can be mined and used to build space-based habitats, or brought back to Earth
答案：water
原文定位：Others are up to one-quarter water, which could be used for life-support or broken down into hydrogen and oxygen to make fuel