Section C
Directions: In this section, you will hear three passages. At the end of each passage, you will hear three or four questions. Both the passage and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D). Then mark the corresponding letter on Answer Sheet 1 with a single line through the centre.
Passage One
[16] Lift-off is usually the most environmentally harmful stage of any space mission, with vast quantities of fuel burnt up in a matter of minutes. For instance, SpaceX’s Falcon 9 gets through 112 tonnes of refined fuel, emitting about 336 tonnes of CO2. This is the equivalent produced by your average car driving almost 70 times around the world. [16] As well as greenhouse gases, rocket engines emit particles that destroy ozone. These issues are growing more pressing with the emergence of commercial spaceflight. There were 114 space launches in 2020, but there may be up to 1,000 per year in future.
Sustainable fuels are the top priority to enable greener space travel. Current spacecraft use a variety of fuels, but most are based on fossil fuels. One potentially greener option is liquid hydrogen and oxygen. Hydrogen can be obtained sustainably by using solar power to break water down into oxygen and hydrogen.
Reusable rockets can cut down on some of the waste associated with spaceflight. [17] Traditionally, boosters, fuel tanks and other components are treated as expendable. But guiding them back to Earth in a controlled manner opens new possibilities—most components from the Falcon 9 can be reused up to 100 times.
Truly environmentally friendly space travel is still some way off. [18] But we already have many of the technologies needed to start limiting its impact on our planet.
短文一
发射通常是任何太空任务中对环境危害最大的阶段,大量燃料在短短几分钟内燃烧殆尽。例如,太空探索技术公司(SpaceX)的“猎鹰9号”火箭消耗112吨精炼燃料,排放约336吨二氧化碳。这相当于一辆普通汽车环绕地球行驶近70圈所产生的排放量。除了温室气体,火箭发动机还会排放破坏臭氧层的微粒。随着商业太空旅行的兴起,这些问题变得愈发紧迫。2020年共有114次太空发射,但未来每年可能高达1000次。
要实现更环保的太空旅行,可持续燃料是首要任务。目前的航天器使用多种燃料,但大多基于化石燃料。一种潜在的更环保选择是液氢和液氧。通过太阳能将水分解为氧和氢,可以可持续地获取氢气。
可重复使用火箭能够减少太空飞行中的部分浪费。传统上,助推器、燃料箱和其他部件都被视为消耗品。但以可控方式将它们引导回地球开启了新的可能性——“猎鹰9号”的大部分部件可重复使用多达100次。
真正环保的太空旅行仍有一段路要走。但我们已经拥有了许多必要的技术,可以开始限制其对地球的影响。
What do we learn from the passage about the lift-off of spacecraft?
问:关于航天器的发射,我们从文章中了解到什么?
解析:
What happens traditionally to boosters, fuel tanks and other components in spaceflight?
问:在航天飞行中,助推器、燃料箱和其他部件传统上是如何处理的?
解析:
What does the passage say we already have regarding spaceflight?
问:这篇文章提到在航天飞行方面我们已经拥有什么(技术)?
解析:
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