地平线系列：火星旅行者指南（2017）

so they've been basically rounded during a transport process.
而它们又太大了
And they're too large to have been moved
不可能被风力移♥动♥和磨圆
and rounded by wind processes,
所以它们只可能是
and so the only way we can actually
被水流所磨圆的
get this rounding is by water flow.
我犹记得这张图像刚传回来的时候
And I remember when this image first came up and we were all
我们都围在一块巨大的屏幕前面观察
huddled around a giant screen looking at this,
事实上我们花了不少时间才醒悟过来
it actually took us a while to really hit home, oh, gosh,
这其实就是第一份
actually, this is the first evidence
从地面传回来的火星上存在过水流的证据
from on the ground of water flow on Mars.
这只是好奇号♥
This was just one in a long list of features
在这个陨击坑中发现的
Curiosity discovered within the crater
诸多类似地球上水流形成的地貌之一
that are reminiscent of features shaped by water here on Earth.
根据这些地质学证据 我认为
I think it's irrefutable that there was once water flowing
火星表面曾有水流这一理论是无可辩驳的
at the surface on Mars, based on the geological evidence.
探测车不仅向我们展示了火星表面的每个细节
Rovers haven't just shown us the surface of Mars in detail,
还证明了在火星着陆有多么困难
they've also shown us how difficult it is to land.
航♥天♥器结构工程师艾比·赫蒂
Spacecraft structures engineer Abbie Hutty
负责确保欧洲第一辆火星车
is responsible for making sure Europe's first rover,
火星生命探测计划
ExoMars,
完好无缺地着陆
stays in one piece.
着陆永远都是探测火星任务
Landing's always going to be one of the trickiest parts
艾比·赫蒂
空中客车防务与航♥天♥公♥司♥
最难的部分
of getting a mission to Mars safely.
很难预测探测车
It's very hard to predict exactly
掉落的具体♥位♥置
what you're going to be dropping down through
因为风速变化很大
because the wind speeds vary dramatically.
还有沙尘暴 会大幅改变大气密度
You get dust storms, which really change the atmospheric density.
最根本的原因是
And fundamentally,
从进入大气顶部
you don't have that much thickness of atmosphere
到撞击地面
between entering it at the top
之间的大气厚度不够
and hitting the ground at the bottom,
因此没有足够的阻力来让探测车减速
so you've not got very much to actually slow yourself down.
刚进入火星大气表面时
When you first hit the top of Mars' atmosphere,
你的速度过快
you are going so fast
你能做的其实只是躲在一块挡热板后面
that really all you can do is just hide behind a heat shield
祈求上天
and hope for the best.
在进入大气层的过程中
During atmospheric entry,
探测车需要承受
the lander will need to withstand temperatures
高达1750摄氏度的温度
reaching up to 1750 Celsius.
最终你会到达一个临界点
So eventually you'll get to the point
那时你就可以释放一顶大得多的降落伞
where you can deploy a much larger parachute,
这样你就能更有效地降低你的速度
so you have a lot more acting to slow yourself down
此时 你的速度已经足够低
and, at this point, you're going slow enough
其实不再需要挡热板了
that you don't really need this heat shield any more,
你就可以将挡热板分离
so you jettison your heat shield.
下一阶段 你可以发射制动火箭
The next stage is you can fire retrorockets,
就是朝你运行的方向发射的火箭
so they're rockets that fire in the direction of travel.
这些制动火箭可以让你降低到
These retrorockets can bring it to a hover about a metre,
距地面一米到一点五米处
a metre and a half above the planet's surface,
之后你就可以走完那最后的一米
and then you can drop that final metre down onto the surface,
直到最终在火星表面着陆
until you're landing there on the surface of Mars.
这是一台铝制样机
This is an aluminium prototype.
而最终的火星生命探测计划将由碳纤维制成
But the final version of ExoMars will be made of carbon fibre,
一种强度极高
an incredibly tough,
具有热稳定性的轻质材料
lightweight material that is thermally stable -
这些都是安全着陆和任务成功必需的特质
all qualities needed for a safe landing and successful mission.
跟任何这样巨大的挑战一样
As with any really grand challenge like this,
火星车要成功通过
there's so many different stages
多个不同阶段
the rover has to go through successfully
整个任务才能算成功
for the whole mission to be declared a success.
我认为真正让人担心的事
I think the things that really are concerning
是那些你控制不了的事
are things that are completely out of your hands.
所以像火箭发射这种
So the rocket launch,
瞬间发生的事
it's one of those kind of split-second things
不是发射成功 就是在空中爆♥炸♥
that it's either going to work or it's going to go up in flames.
着陆同样也是
And then the landing as well
一件有挑战性的事
is another really challenging aspect
过去许多任务正是在这一步失败
and that's where a lot of missions have failed in the past,
所以当你确定着陆成功时
so definitely, when you get that safe landing confirmed,
你确实可以松一大口气
that's going to be a big relief.
像艾比一样的工程师
Engineers like Abbie
总有一天会设计出
will one day design vehicles
第一次带着人类登上火星的运载工具
to take the first human travellers to Mars.
但是还有一个问题 该在哪着陆呢
But the question remains, where should you land?
离开地球七个月后
Seven months after leaving Earth behind,
火星来访者将会欣赏到
Martian visitors will be met with astounding views
火星上令人震惊的景色
of the Red Planet
以及亟待探索的广阔地貌
and vast landscapes calling out to be explored.
但最完美的着陆点可能会让你吃惊
But the perfect spot may surprise you.
地点 水手谷
长4000千米 宽200千米 深10千米
这就是水手谷
This is Valles Marineris,
以美国航♥天♥局
named after Mariner 9,
发现该峡谷的水手9号♥命名
the NASA mission that discovered it.
该峡谷的跨度令人惊叹
The scale of the canyon is breathtaking.
就像地球上的科罗拉多大峡谷 但是超大版的
It is like the Grand Canyon on Earth, but super-size.
水手谷
有的地方 其深度达到十千米
In places, its walls plunge 10km down,
其独特的地质构造
a unique geological formation
是火星上其他任何地方都无法比拟的
not matched anywhere else on the planet.
得益于大峡谷体系的地质情况
And it's thanks to this geology that this vast canyon system
使它成为了理想的着陆点
makes the ideal landing site on Mars...
宇宙地质学家吉姆·赖斯博士
As astro geologist Dr Jim Rice
可以证实这一点
can testify to.
自1994年火星探路者任务
He's been involved in selecting Mars landing sites
他参与了美国宇航局
for every NASA mission
每一次着陆点的选择
since Mars Pathfinder in 1994.
我们需要的是比较平坦的地方
You want something fairly flat,
没有很多岩石以及尘土
not too rocky, not too dusty.
吉姆·赖斯博士 行星科学研究所
因为我们在进入火星大气层时
And because we use parachutes to help slow us down
利用降落伞来减速
in the entry into the Martian atmosphere,
海拔需要低一些
a little bit lower in elevation.
景色也是相当令人惊叹
And the views would be breathtaking, too.
水手谷是一个非常棒的地方
Valles Marineris is a great spot
就像地球上的科罗拉多大峡谷一样
because it's basically kind of like the Grand Canyon here,
由一位巨人外科医生拿着手术刀
it's like someone's taken a giant surgeon with a scalpel
划开一个口子 打开了火星的地壳
and made an incision and opened up the crust of the planet,
让你看到里面更深处的样子
allowing you to see deeper down
地质上的更深处意味着更久远的历史
and deeper down in geology is further back in history.
正是火星内部的这些景观
It's this view inside the planet
深深吸引着赖斯博士
that is the big draw for Dr Rice.
但对于我们大多数人来说
But for most of us,
单是这宏伟的规模就有足够吸引力了
the epic scale alone would be enticing enough.
该峡谷的长度是科罗拉多大峡谷的十倍
Now, that canyon is ten times longer than the Grand Canyon here.
深度是它的四倍 宽度是它的十二倍
It's four times deeper and about 12 times wider.
换个角度来想
Another way to think about it is the vast expanse of this canyon,
它的长度相当于从纽约到洛杉矶的距离
the length of it, would be from New York City to Los Angeles,
称得上是太阳系的大峡谷
so that truly is the Grand Canyon of the Solar System.
火星奥德赛轨道飞行器 2002年2月至2005年11月
水手谷对所有火星来访者
Valles Marineris would provide the ultimate draw
都具有终极吸引力
for any Martian visitor.
但它吸引人的不只是其景色
But it's not just the views that are attractive.
深入探索水手谷
Touching down inside Valles Marineris
火星快车 2004年5月28日
会帮我们解答一个长久以来
could help answer long-held questions
关于峡谷形成的问题
about the chasm's formation.
像这样在轨道上拍摄的图片
Images like this, taken from orbit,
会提供给我们一些其历史成因的线索
give us some clues to its history.
一种说法是古老的火山爆发
One theory is that ancient volcanoes
撕裂了火星的表面
ripped apart the surface,
形成了裂缝
creating a rift
水流持续冲刷侵蚀裂缝