(单词翻译:单击)
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.
发射通常是任何太空任务中对环境最有害的阶段，因为大量燃料会在几分钟内燃烧殆尽。
For instance, SpaceX's Falcon 9 gets through 112 tons of refined fuel, emitting about 336 tons of CO2.
例如，SpaceX的猎鹰9号消耗了112吨精炼燃料，排放了约336吨二氧化碳。
This is the equivalent produced by your average car driving almost 70 times around the world, as well as greenhouse gases.
这相当于普通汽车绕地球行驶近70圈所产生的排放量，以及温室气体。
Rocket engines emit particles that destroy ozone. These issues are growing more pressing with the emergence of commercial spaceflight.
火箭发动机排放的颗粒会破坏臭氧层。随着商业航天的出现，这些问题变得越来越紧迫。
There were 114 space launches in 2020, but there may be up to 1,000 per year in future.
2020年有114次太空发射，但未来每年可能会有多达1000次。
Sustainable fuels are the top priority to enable greener space travel.
可持续燃料是实现更环保的太空旅行的首要任务。
Current spacecraft use a variety of fuels,but most are based on fossil fuels.
目前的航天器使用各种燃料，但大多数都是基于化石燃料。
One potentially greener option is liquid hydrogen and oxygen.
一种潜在的更环保的选择是液态氢和氧。
Hydrogen can be obtained sustainably by using solar power to break water down into oxygen and hydrogen.
可以通过利用太阳能将水分解成氧气和氢气来可持续地获取氢气。
Reusable rockets can cut down on some of the waste associated with spaceflight.
可重复使用的火箭可以减少与航天相关的一些浪费。
Traditionally, boosters, fuel tanks, and other components are treated as expendable.
传统上，助推器、燃料箱和其他部件被视为消耗品。
But guiding them back to Earth in a controlled manner opens new possibilities.
但以受控的方式引导它们返回地球开辟了新的可能性。
Most components from the Falcon 9 can be reused up to 100 times.
猎鹰9号的大多数部件可以重复使用多达100次。
Truly environmentally friendly space travel is still some way off.
真正环保的太空旅行仍然遥遥无期。
But we already have many of the technologies needed to start limiting its impact on our planet.
但我们已经拥有许多必要的技术来开始限制其对地球的影响。
Question 16. What do we learn from the passage about the lift-off of spacecraft?
问题16. 关于航天器的发射，我们从文章中了解到什么？
Question 17. What happens traditionally to boosters, fuel tanks, and other components in spaceflight?
问题17 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？
Question 18. What does the passage say we already have regarding spaceflight?
问题18 这篇文章提到在航天飞行中我们已经拥有什么技术？
