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When it comes to landing spacecraft on planets, or moons, or back here on earth – Mars sucks.
相比着陆行星、卫星或地球而言，火星太糟糕了。
There's a lower success rate landing on Mars than on Venus, the moon, the earth, even Saturn's moon Titan.
着陆火星的成功率比金星、月球、地球，甚至比土星的泰坦都要低。
And in large part, this is because Mars's atmosphere is in the perfect goldilocks zone of being a total headache.
大部分原因是因为火星的大气层刚好处于棘手地带。
On the moon (or an asteroid) you can use lightweight spacecraft made essentially out of tinfoil
在月球（或小行星）上，你可以用锡纸制成的轻型航天器
because there's no air to cause drag or pressure or heat.
因为月球上没有空气，不会造成阻力、压力或热。
Essentially, you save weight not having heat shields or thick walls,
事实上，你不需要防护罩或厚厚的外壳减重
but need to use rockets to land in what's called a "powered descent."
但需要火箭在所谓的“动力下降”中着陆。
On earth, or Venus, or Titan, there's enough air that you can land largely unpowered,
在地球、金星或泰坦上，有足够的空气可以让你在没有动力的情况下着陆
first by slowing down with a heat shield and atmospheric drag, and then with parachutes.
首先用防护罩和大气的阻力，再用降落伞减速。
So you use a lot of weight for heat shields and walls and parachutes, but don't need big rockets or lots of fuel to land.
所以你需要很重的防护罩、外壳和降落伞，但却不需要巨大的火箭或很多燃料。
However, the air on Mars is literally the worst of both worlds – thick enough that you actually have to deal with it with heat shields and walls,
但火星上的空气确实是最糟糕的——它厚到你不得不用防护罩和外壳来应付它
but thin enough that it doesn't help you slow down much and you also need to use rockets.
但也薄到无法帮助你减速，因此你还需要使用火箭。
Mars is simply a challenging place to land a spacecraft, which is why we've tried so many different and crazy techniques for landing there:
火星对飞船着陆而言是一个充满挑战的地方，因此我们尝试过非常多不同的疯狂的着陆技术：
we've landed landers and rovers using retrorockets, in inflatable bouncy airbags, by being lowered from a hovering sky crane,
包括制动火箭、可充气气囊、用空中起重机
all of which ALSO used heat shields and parachutes and rocket powered descent before the last stage of landing.
所有这些方式，在着陆的最后阶段都用到了防护罩和降落伞以及火箭动力下降。
And space agencies are testing other crazy things like giant supersonic parachutes and inflatable innertubes around landers
航天机构正在测试其他疯狂的东西，比如巨大的超音速降落伞以及在登陆器周围配备充气内胎
to increase their surface area and help them slow down more in the thin air before landing (probably still with rockets, or sky cranes).
以增强它们的表面区域并帮助它们在着陆前在稀薄的空气中减速（可能还是要用到火箭，或空中起重机）。
Yes, you heard that right – it's possible that when the first humans land on Mars, we may do so in an inflatable donut.
是的，你没听错—可能第一个太空人上火星时，他要待在一个充气甜甜圈里。
Or we'll just skim at a really low angle past the tops of mountains for a really long time to slow down enough...
或者我们要以很低的角度不断越过山顶，慢慢减速。
