Dear Fara, December 18, 2050
So you're going to Mars! I suppose you've read books about Mars. But there's a lot you won't learn just by reading, you had better practise so much. You know, what a wonderful time we live in! Here are some pointers:
The cheapest round trip comes to about $30,000. The cost depends upon how close Mars is to Earth at the time. You may be surprised to know that the shortest trip costs the most! On short trips you need great changes of speed as you jump from one orbit1 to the other. And in space, speed, rather than distance, costs money. You won't be able to take very much with you. But it really doesn't matter. You can buy what you need when you get to Mars. What's more, you'll throw it away when you leave.
Take a camera by all means. You can get some wonderful shots when you leave Earth and as you come near Mars. And you can sell a good camera on Mars for five times its price here. Your spaceship will probably leave from a high mountaintop in New Guinea. Why there? It's on the equator2. A spaceship taking off from there gets the 1000-mile-an-hour boost3 of the Earth's spin4. And there's the whole ocean for empty fuel tanks to fall into.
There's nothing to worry during the takeoff. You just lie on a couch5 and fasten your safety belt. Then you put in your earplugs6 and relax7. In about a minute you'll feel the strong pull back toward Earth. The noise is loud and painful. But it lasts only five minutes. Then you'll be in orbit. About 30 minutes after takeoff, you'll reach Space Station One. Your spaceship will match its speed to that of the station. Then clang8! Air locks will hook9 the ferry10 to the station. An air lock is a kind of tunnel11. The one on your spaceship will fit into a larger one on the station.
When your spaceship is “hooked on”, you can undo your safety belt. Then you'll know what it's like to be weightless. But hang on to the rope while passing through the air lock. Don't try to fly around like a bird. You might get hurt!
At the space station, you'll spend your time in the lookout room. Everyone does this, no matter how many times he has been out in space. The view is wonderful. You've never really seen the stars like this before.
Several hours later you'll go aboard your space liner. If it's a big one, there'll be about 100 passengers and a crew of 20. Most of your fellow passengers will be scientists or builders with jobs to do on Mars. Your cabin12 looks like a large shelf. Here you'll may have trouble sleeping. You'll miss your weight. But your bed has special covers to keep you from floating off!
You can keep in touch with Earth and Mars by space radio and space internet. And the liner will have a good library of microbooks and E-books. But I'll bet you'll spend a lot of time at the telescope13. Having the stars all around you is something you'll never forget.
The first thing you'll see on Mars will be one of the polar14 ice caps. In the week before you land you'll get to know the geography of Mars. You'll land first on Phobos15, Mars' inner moon. It's about 4000 miles from there to Mars, a trip of about three hours. Your ferry has to go halfway around Mars before it loses enough speed to land.
As you come in over Port Lowell, you'll see a cluster16 of bubbles17. These are the plastic domes18 of the city. When the sun catches them, they are a very pretty sight. You'll spend most of your time at Port Lowell, the largest city. Like most of the cities, it is in the southern part of Mars. The northern part is nearly all desert.
When you go outside the domes, you'll have to take along your own air for breathing. You'll see people going around without an air supply. But don't you try it. These people have been on Mars for years. They have learned to make one lungful of air last for several minutes.
For short trips you may ride in a “sand flea19”, a kind of jeep20. For longer trips, you may fly. You'll find that it is very cold on Mars. The warmest I've ever known it to be is in the 80's of Fahrenheit21. And that's unusual. I've heard that it has been as cold as 190 degrees below zero! But you'll be warm in your suit, made to prevent your body heat from escaping. Finally, if you are free, I hope you can bring me some new stamps from Mars.
Have a great and wonderful trip!
Your Friend,
Miles
亲爱的法拉： 2050年12月18日
这么说你要去火星了！我想你已经读过有关火星的书，但是有许多东西光靠读书是学不到的。你最好亲身体验一下。你要知道，我们生活在一个多么了不起的时代呀！这里有几条指南供你参考：
来回旅行一趟最便宜的花销接近三万美元。这个价格取决于火星当时离地球有多远。你可能会很吃惊地发现最短的行程费用却最贵。在短途旅行中从一个运行轨道跳到另一个运行轨道时，你需要极大地改变速度。在太空里旅行，费钱的是速度而不是距离。你不能带很多东西，但这其实没关系。当到达火星后你可以购买需要的东西。而且，离开时你会把它们都扔掉的。
务必要带一个照相机，在离开地球和靠近火星的时候，你可以拍到一些奇妙的镜头，你还可以在火星上以五倍于这里的价格把一个好照相机卖掉。你的宇宙飞船很可能在新几内亚的一座高山顶上发射升空。为什么在那儿呢？因为它在赤道上，飞船从哪儿起飞可以借助地球的自转产生的每小时1000英里的助推力，而且那儿还有一大片海洋，正好接收掉下来的空燃料箱。
起飞没什么让人担心的，你只需躺在靠椅上系紧安全带。然后戴上耳塞，放松就可以了。大约一分钟后，你会感到一股把你拖回地球的强大拉力，噪音刺耳，让人不舒服，但仅仅持续五分钟，然后你就进入了运行轨道。起飞后大约三十分钟，你就到达了一号太空站。这时你的宇宙飞船就会把速度调整得同太空站一致，然后哐当一声！气闸室会把渡运飞船和太空站对接起来，气闸室是一种隧道，宇宙飞船上的气闸室会塞进太空站较大的气闸室里。
当飞船对接之后，你就可以解开安全带了。然后你就会知道失重是什么滋味。但是你通过气闸室的时候要抓住绳子，切不要像鸟儿一样乱飞，那样你会受伤的。
在太空站里，你将会在瞭望室消磨时光，不管到过太空多少次，每个人都是如此。景色非常奇妙，你以前从未真正地看见过这样的星星！
几个小时以后你就会登上太空班机，如果是个大型客机，它会容纳大约100个旅客和20个人的机组人员，你的旅伴大多是到火星上去工作的科学家或建设者。你的舱位像一个大书架，（在这上面）你可能很难入睡，你的体重会减轻。但你床上有特殊的被子可以防止你浮起来！
你可以通过太空电台和太空互联网同地球和火星保持联系。班机上会有一个很好的图书馆，里面有许多微缩书籍和电子图书。但我敢打赌，你一定会在望远镜前花去很多时间，四周群星闪耀足以让你终生难忘。
在火星上你看到的第一个东西会是一个极地冰帽，在着陆前的一周内，你将了解到火星的地理概貌。你将先在火星的里层卫星火卫一上降落，从那里到火星约有4000英里，大约三个小时的路程。渡运飞船须绕火星半圈才能让速度变慢，足以降落。
当你飞临洛威尔港上空时，你会看到一串水泡。这些都是该城的一个个塑料圆屋顶。当阳光照射到上面时，景色真是非常漂亮！你的大部分时间都将在最大的城市洛威尔港度过，同大多数火星城市一样，该城也在火星的南半部。火星的北半部几乎全是荒漠。
如果你要到圆屋顶外面去，就必须带上供你呼吸用的空气。你会看到人们走来走去，并不带空气。但你可别试着这样做。 这些人在火星上已经呆了许多年了，早已学会吸满一口气后几分钟都不呼吸。
短途旅行时你可以乘坐一种叫“沙蚤”的吉普车，长途旅行时可以坐飞机。你会发现火星上很冷。据我所知火星上最暖和的温度是华氏80几度。但这也不常见。我听说最冷时曾冷到零下190度！但你穿的衣服是专门防止体温散发的，所以穿着衣服是很暖和的。最后，假如你有空的话，别忘了给我带一些火星上的新邮票。
祝你有一个愉快而神奇的旅行！
你的朋友，
麦尔斯
1. orbit n． 轨道
2． equator n． 赤道
3． boost n． 上推
4． spin [spin] n． 旋转
5． couch n． (文学)床, 睡椅
6． earplug n． 耳塞
7． relax v． 放松, 休息
8． clang n． 铿锵声
9． hook [huk] v． 钩住
10． ferry n． 摆渡, 渡船
11． tunnel n． 隧道, 地道
12． cabin n． 船舱
13． telescope n． 望远镜
14． polar adj． [天]两极的, 极地的
15． Phobos n． [天]火卫一
16． cluster n． 串, 丛
17． bubble n． 泡沫
18． dome n． 圆屋顶
19． flea n． 跳蚤
20． jeep n． 吉普车
21． Fahrenheit n． 华氏温度