TED2015
Fred Jansen: How to land on a comet
福瑞得．詹森: 如何在慧星上登陸
Filmed:
Readability: 4
1,308,991 views
身為羅塞塔任務的主管，福瑞得．詹森於2014年成功完成探測器登陸67P/丘留莫夫．格拉西緬科慧星的壯舉。透過本回引人入勝的輕鬆演講，詹森透露如何精密計算，從遠在地球5億公里外，引導菲萊號探測器登陸慧星──同時也分享沿途拍攝的一些精彩照片。
Fred Jansen - Space explorer
As manager of the Rosetta mission, Fred Jansen is in charge of the project that could be instrumental in uncovering clues to the origins of life on Earth. Full bio
As manager of the Rosetta mission, Fred Jansen is in charge of the project that could be instrumental in uncovering clues to the origins of life on Earth. Full bio
Double-click the English transcript below to play the video.
00:12
I'd like to take you on the epic quest
of the Rosetta spacecraft.
of the Rosetta spacecraft.
0
717
4797
我將帶領大家跟著羅塞塔號太空船
進行史詩般的探險。
進行史詩般的探險。
00:17
To escort and land the probe on a comet,
1
5514
4026
護送這個探測器在一顆彗星上登陸，
00:21
this has been my passion
for the past two years.
for the past two years.
2
9540
3190
一直是我這過去兩年來的熱情所在。
00:25
In order to do that,
3
13450
1095
為此，
00:26
I need to explain to you something
about the origin of the solar system.
about the origin of the solar system.
4
14545
3470
我需要向大家解釋一些關於太陽系起源的東西。
00:30
When we go back
four and a half billion years,
four and a half billion years,
5
18015
2223
讓我們回到45億年前，
00:32
there was a cloud of gas and dust.
6
20238
1719
有個充滿氣體和灰塵的雲團。
00:33
In the center of this cloud,
our sun formed and ignited.
our sun formed and ignited.
7
21957
4527
在這個雲團的中心，
我們的太陽在那裡形成並燃燒。
我們的太陽在那裡形成並燃燒。
00:38
Along with that, what we now know
as planets, comets and asteroids formed.
as planets, comets and asteroids formed.
8
26484
5711
同時，今日所知的行星、彗星和小行星跟著形成。
00:44
What then happened, according to theory,
9
32195
3413
根據理論，接下來，
00:47
is that when the Earth had cooled down
a bit after its formation,
a bit after its formation,
10
35608
4017
隨著地球形成並逐漸冷卻，
00:51
comets massively impacted the Earth
and delivered water to Earth.
and delivered water to Earth.
11
39625
4771
大量彗星撞擊地球，並帶來了水。
00:57
They probably also delivered
complex organic material to Earth,
complex organic material to Earth,
12
45082
4434
它們可能還給地球帶來了複雜的有機物。
01:01
and that may have bootstrapped
the emergence of life.
the emergence of life.
13
49516
3390
正是這些有機物引發了生命的出現。
01:04
You can compare this to having
to solve a 250-piece puzzle
to solve a 250-piece puzzle
14
52906
3460
這過程猶如必須拼湊一幅250片的拼圖，
01:08
and not a 2,000-piece puzzle.
15
56366
3204
而非2000片。
01:11
Afterwards, the big planets
like Jupiter and Saturn,
like Jupiter and Saturn,
16
59570
3483
之後，像木星和土星之類的大行星，
01:15
they were not in their place
where they are now,
where they are now,
17
63053
2578
它們尚未在今日所在位置，
01:17
and they interacted gravitationally,
18
65631
2647
透過彼此重力吸引，
01:20
and they swept the whole interior
of the solar system clean,
of the solar system clean,
19
68278
3552
它們將整個內太陽系空間清掃乾淨。
01:23
and what we now know as comets
20
71830
1602
至於今日所知之彗星，
01:25
ended up in something
called the Kuiper Belt,
called the Kuiper Belt,
21
73432
2113
最後則落入所謂柯伊伯帶之內。
01:27
which is a belt of objects
beyond the orbit of Neptune.
beyond the orbit of Neptune.
22
75545
3668
這是一條位於海王星軌道之外的天體聚集帶。
01:31
And sometimes these objects
run into each other,
run into each other,
23
79213
3693
有時這些天體會相互碰撞，
01:34
and they gravitationally deflect,
24
82906
3065
導致引力偏向，
01:37
and then the gravity of Jupiter
pulls them back into the solar system.
pulls them back into the solar system.
25
85971
4457
此時，木星的引力會將它們拉回太陽系。
01:42
And they then become the comets
as we see them in the sky.
as we see them in the sky.
26
90428
3692
然後，它們就變成我們在天空中所見的彗星。
01:46
The important thing here to note
is that in the meantime,
is that in the meantime,
27
94120
3274
重要的一點是，在此期間，
01:49
the four and a half billion years,
28
97394
2299
在這45億年間，
01:51
these comets have been sitting
on the outside of the solar system,
on the outside of the solar system,
29
99693
3182
這些彗星一直安坐於太陽系之外，
01:54
and haven't changed --
30
102875
1415
並且從沒變過——
01:56
deep, frozen versions of our solar system.
31
104290
2903
就像沉底，凍結版的太陽系。
01:59
In the sky, they look like this.
32
107193
2089
在天空中，它們看起來像這樣。
02:01
We know them for their tails.
33
109282
1951
我們靠慧尾認識它們，
02:03
There are actually two tails.
34
111233
1671
慧尾其實有兩條。
02:04
One is a dust tail,
which is blown away by the solar wind.
which is blown away by the solar wind.
35
112904
3855
一條是塵埃尾，因太陽風吹拂而生。
02:08
The other one is an ion tail,
which is charged particles,
which is charged particles,
36
116759
3645
另一條是離子尾，含帶電粒子，
02:12
and they follow the magnetic field
in the solar system.
in the solar system.
37
120404
2739
其方向遵循太陽系內磁場方向。
02:15
There's the coma,
38
123143
1149
這是慧髮，
02:16
and then there is the nucleus,
which here is too small to see,
which here is too small to see,
39
124292
2907
然後這是慧核，小到看不見，
02:19
and you have to remember
that in the case of Rosetta,
that in the case of Rosetta,
40
127199
2490
但是別忘記，就羅塞塔號而言，
02:21
the spacecraft is in that center pixel.
41
129689
2177
太空船就在中央那個像素裡。
02:23
We are only 20, 30, 40 kilometers
away from the comet.
away from the comet.
42
131866
4110
我們距離彗星只有20 、30、 40公里。
02:27
So what's important to remember?
43
135976
2321
其重要性何在？
02:30
Comets contain the original material
from which our solar system was formed,
from which our solar system was formed,
44
138297
4869
彗星中含有太陽系形成時的原始物質，
02:35
so they're ideal to study the components
45
143166
2360
因此，其成份是我們研究地球
02:37
that were present at the time
when Earth, and life, started.
when Earth, and life, started.
46
145526
4265
及生命起源時期的絕佳對象。
02:41
Comets are also suspected
47
149791
1882
彗星還疑似
02:43
of having brought the elements
which may have bootstrapped life.
which may have bootstrapped life.
48
151673
4271
帶來了那些引發生命起源的元素。
02:47
In 1983, ESA set up
its long-term Horizon 2000 program,
its long-term Horizon 2000 program,
49
155944
4365
1983年，歐洲太空總署(ESA)
開啟了長期的地平線2000計畫，
開啟了長期的地平線2000計畫，
02:52
which contained one cornerstone,
which would be a mission to a comet.
which would be a mission to a comet.
50
160309
3924
其中包含一塊重要基石，即彗星探索任務。
02:56
In parallel, a small mission to a comet,
what you see here, Giotto, was launched,
what you see here, Giotto, was launched,
51
164233
4890
同時期，為了一項小型的彗星探索任務，
畫面上的喬托號發射升空，
畫面上的喬托號發射升空，
03:01
and in 1986, flew by the comet of Halley
with an armada of other spacecraft.
with an armada of other spacecraft.
52
169123
6206
喬托號於1986年飛掠過哈雷彗星，
前後跟著一大群其他太空船。
前後跟著一大群其他太空船。
03:07
From the results of that mission,
it became immediately clear
it became immediately clear
53
175329
3571
通過那次任務的結果，一件事變得很清楚，
03:10
that comets were ideal bodies to study
to understand our solar system.
to understand our solar system.
54
178900
5187
那就是彗星是用來研究太陽系的理想天體。
03:16
And thus, the Rosetta mission
was approved in 1993,
was approved in 1993,
55
184087
4512
因此，1993年批准了羅塞塔號任務，
03:20
and originally it was supposed
to be launched in 2003,
to be launched in 2003,
56
188599
3635
一開始，它應該是在2003年發射的，
03:24
but a problem arose
with an Ariane rocket.
with an Ariane rocket.
57
192234
2624
卻因亞利安火箭出現問題而取消。
03:26
However, our P.R. department,
in its enthusiasm,
in its enthusiasm,
58
194858
3065
不過，我們的公關部門，充滿熱情，
03:29
had already made
1,000 Delft Blue plates
1,000 Delft Blue plates
59
197923
2222
他們早已製作了1000枚代爾夫特藍陶盤，
03:32
with the name of the wrong comets.
60
200145
2390
並印上了那些錯誤的彗星名字。
03:34
So I've never had to buy any china since.
That's the positive part.
That's the positive part.
61
202535
3567
因此從那以後我就不需再買任何瓷器。
這也算是其正向的一面。
這也算是其正向的一面。
03:38
(Laughter)
62
206102
1719
（笑聲）
03:39
Once the whole problem was solved,
63
207821
1880
解決了所有問題之後，
03:41
we left Earth in 2004
64
209701
3181
羅塞塔號於2004年離開地球，
03:44
to the newly selected comet,
Churyumov-Gerasimenko.
Churyumov-Gerasimenko.
65
212882
3088
飛向重新選定的丘留莫夫·格拉西緬科彗星。
03:47
This comet had to be specially selected
66
215970
2856
這顆彗星是特別挑選的，
03:50
because A, you have to
be able to get to it,
be able to get to it,
67
218826
2654
因為首先，你必須能到得了，
03:53
and B, it shouldn't have been
in the solar system too long.
in the solar system too long.
68
221480
2781
其次，它必須沒在太陽系長期待過。
03:56
This particular comet has been
in the solar system since 1959.
in the solar system since 1959.
69
224261
3947
這顆特別的彗星從1959年開始來到太陽系。
04:00
That's the first time
when it was deflected by Jupiter,
when it was deflected by Jupiter,
70
228208
3315
那是它受木星偏向後第一次來到太陽系，
04:03
and it got close enough
to the sun to start changing.
to the sun to start changing.
71
231523
2977
且靠近太陽近到足夠出現變化。
04:06
So it's a very fresh comet.
72
234500
1651
所以這是一顆非常新的彗星。
04:08
Rosetta made a few historic firsts.
73
236611
2891
羅塞塔號取得了好些歷史性的第一。
04:11
It's the first satellite to orbit a comet,
74
239502
2516
它是首顆環繞彗星的人造衛星，
04:14
and to escort it throughout
its whole tour through the solar system --
its whole tour through the solar system --
75
242018
3622
並跟著慧星周遊整個太陽系——
04:17
closest approach to the sun,
as we will see in August,
as we will see in August,
76
245640
3298
八月將到達近日點，
04:20
and then away again to the exterior.
77
248938
2321
然後離開太陽系。
04:23
It's the first ever landing on a comet.
78
251259
2601
這是首次有太空船在彗星上登陸。
04:25
We actually orbit the comet
using something which is not
using something which is not
79
253860
3692
在環繞這顆彗星飛行時，我們實際用到一項
04:29
normally done with spacecraft.
80
257552
1449
其他太空船罕用的技術。
04:31
Normally, you look at the sky and you know
where you point and where you are.
where you point and where you are.
81
259001
3635
通常，你望向天空，就能知道你的方位和座標。
04:34
In this case, that's not enough.
82
262636
2136
但是為了環繞慧星，那還不夠。
04:36
We navigated by looking
at landmarks on the comet.
at landmarks on the comet.
83
264772
3298
我們要靠彗星上的地標來導航。
04:40
We recognized features --
boulders, craters --
boulders, craters --
84
268070
2475
我們辨別一些特徵——卵石、坑洞——
04:42
and that's how we know where we are
respective to the comet.
respective to the comet.
85
270545
4017
這樣才能知道我們相對於彗星的位置。
04:46
And, of course, it's the first satellite
to go beyond the orbit of Jupiter
to go beyond the orbit of Jupiter
86
274562
4529
當然，這也是使用太陽能電池的太空船
04:51
on solar cells.
87
279091
1201
第一次飛越木星的軌道。
04:52
Now, this sounds more heroic
than it actually is,
than it actually is,
88
280292
2327
這聽起來似乎是項英雄事蹟，但事實不完全如此，
04:54
because the technology
to use radio isotope thermal generators
to use radio isotope thermal generators
89
282619
5096
理由是那時候歐洲還沒有
放射性同位素熱電源的技術可用，
放射性同位素熱電源的技術可用，
04:59
wasn't available in Europe at that time,
so there was no choice.
so there was no choice.
90
287715
3298
所以當時別無選擇。
05:03
But these solar arrays are big.
91
291013
1577
不過這些太陽能電池板很大。
05:04
This is one wing, and these are not
specially selected small people.
specially selected small people.
92
292590
3275
這是它的一隻翅膀，而這些是人，
沒有特意挑矮子。
沒有特意挑矮子。
05:07
They're just like you and me.
93
295865
1834
他們是跟你我一樣的正常人。
05:09
(Laughter)
94
297699
2391
（笑聲）
05:12
We have two of these wings,
65 square meters.
65 square meters.
95
300090
4201
我們有兩隻翅膀，共65平方公尺。
05:16
Now later on, of course,
when we got to the comet,
when we got to the comet,
96
304291
3019
當然，隨後當我們到達這顆彗星時，
05:19
you find out that 65 square meters of sail
97
307310
3529
你會發現，讓這65平方公尺的巨帆
05:22
close to a body which is outgassing
is not always a very handy choice.
is not always a very handy choice.
98
310839
5642
向一個正在釋放氣體的天體靠近並不是很方便的設計。
05:28
Now, how did we get to the comet?
99
316481
2044
我們是怎麼到達這顆彗星呢？
05:30
Because we had to go there
for the Rosetta scientific objectives
for the Rosetta scientific objectives
100
318525
3668
因為我們須要到一個十分遙遠的地方
去完成羅塞塔號的
去完成羅塞塔號的
05:34
very far away -- four times the distance
of the Earth to the sun --
of the Earth to the sun --
101
322193
3808
科學任務——距離為地球到太陽的4倍——
05:38
and also at a much higher velocity
than we could achieve with fuel,
than we could achieve with fuel,
102
326001
4110
而且須要以一個遠超過我們用燃料
所能達到的速度飛行。
所能達到的速度飛行。
05:42
because we'd have to take six times as
much fuel as the whole spacecraft weighed.
much fuel as the whole spacecraft weighed.
103
330111
4319
如果要達到這速度，
我們得攜帶六倍於太空船本身重量的燃料。
我們得攜帶六倍於太空船本身重量的燃料。
05:46
So what do you do?
104
334430
1410
所以你會怎麼做？
05:47
You use gravitational flybys, slingshots,
105
335840
3483
你會採用重力場飛掠法，即彈弓原理，
05:51
where you pass by a planet
at very low altitude,
at very low altitude,
106
339323
3367
以非常低的高度，飛掠行星，
05:54
a few thousand kilometers,
107
342690
1765
大概幾千公里高，
05:56
and then you get the velocity
of that planet around the sun for free.
of that planet around the sun for free.
108
344455
4713
這樣你就能免費獲得那顆行星的公轉速度。
06:01
We did that a few times.
109
349168
2043
我們這樣做了好多次。
06:03
We did Earth, we did Mars,
we did twice Earth again,
we did twice Earth again,
110
351211
2479
我們利用過地球、火星 ，然後又第二次使用地球，
06:05
and we also flew by two asteroids,
Lutetia and Steins.
Lutetia and Steins.
111
353690
3968
我們還飛掠了兩顆小行星，司琴星，以及斯坦斯。
06:10
Then in 2011, we got so far from the sun
that if the spacecraft got into trouble,
that if the spacecraft got into trouble,
112
358318
4665
然後到了2011年，我們已經距離太陽夠遠了，
如果這時太空船遇到什麼問題，
如果這時太空船遇到什麼問題，
06:14
we couldn't actually
save the spacecraft anymore,
save the spacecraft anymore,
113
362983
3809
事實上，我們再也沒辦法拯救它了，
06:18
so we went into hibernation.
114
366792
1973
所以我們進入冬眠狀態。
06:20
Everything was switched off
except for one clock.
except for one clock.
115
368765
3338
除了一個時鐘外，所有其他儀器都關掉了。
06:24
Here you see in white the trajectory,
and the way this works.
and the way this works.
116
372103
3511
畫面上白線為太空船的運動軌跡，
可看出其工作原理。
可看出其工作原理。
06:27
You see that from
the circle where we started,
the circle where we started,
117
375614
2443
你看，從一開始出發的這個圓，
06:30
the white line, actually you get
more and more and more elliptical,
more and more and more elliptical,
118
378057
3816
沿著白線，我們看到軌跡變成越來越狹長的橢圓，
06:33
and then finally we approached the comet
119
381873
2949
2014年5月，我們終於靠近彗星。
06:36
in May 2014, and we had to start
doing the rendezvous maneuvers.
doing the rendezvous maneuvers.
120
384822
4365
然後我們開始進行會合動作。
06:41
On the way there, we flew by Earth and we
took a few pictures to test our cameras.
took a few pictures to test our cameras.
121
389187
4597
在途中，我們飛經地球
並拍了一些照片以測試我們的相機。
並拍了一些照片以測試我們的相機。
06:45
This is the moon rising over Earth,
122
393784
2178
這是月球從地平線上升的景像，
06:47
and this is what we now call a selfie,
123
395962
1955
這是我們現在所稱的自拍，
06:49
which at that time, by the way,
that word didn't exist. (Laughter)
that word didn't exist. (Laughter)
124
397917
3692
順便說一下，那個時候“自拍”
這個詞還不存在。（笑聲）
這個詞還不存在。（笑聲）
06:53
It's at Mars. It was taken
by the CIVA camera.
by the CIVA camera.
125
401609
2971
這是在火星上方，
由彗星紅外與可見光分析儀 (CIVA) 相機所拍攝。
由彗星紅外與可見光分析儀 (CIVA) 相機所拍攝。
06:56
That's one of the cameras on the lander,
126
404580
2182
那是登陸器上的一台相機，
06:58
and it just looks under the solar arrays,
127
406762
2415
從太陽能電池板下方望出的景像，
07:01
and you see the planet Mars
and the solar array in the distance.
and the solar array in the distance.
128
409177
4273
你能看到火星及遠處的太陽能電池板。
07:05
Now, when we got out
of hibernation in January 2014,
of hibernation in January 2014,
129
413450
5668
當我們在2014年1月從冬眠中甦醒後，
07:11
we started arriving at a distance
130
419118
1785
5月份我們到達距離慧星
07:12
of two million kilometers
from the comet in May.
from the comet in May.
131
420903
2833
200萬公里的地方。
07:15
However, the velocity
the spacecraft had was much too fast.
the spacecraft had was much too fast.
132
423736
4109
然而，這時太空船的速度太快了。
07:19
We were going 2,800 kilometers an hour
faster than the comet, so we had to brake.
faster than the comet, so we had to brake.
133
427845
6061
我們的時速比這顆彗星快2800 公里，
因此我們需要刹一刹車。
因此我們需要刹一刹車。
07:25
We had to do eight maneuvers,
134
433906
1857
我們作了8次的減速動作，
07:27
and you see here,
some of them were really big.
some of them were really big.
135
435763
2577
你看這圖，其中的一些減速幅度真的很大。
07:30
We had to brake the first one
by a few hundred kilometers per hour,
by a few hundred kilometers per hour,
136
438340
6024
我們的第一次減速需要將時速降低數百公里，
07:36
and actually, the duration of that
was seven hours,
was seven hours,
137
444364
4310
這個過程實際花了7個小時，
07:40
and it used 218 kilos of fuel,
138
448674
2948
並消耗了218公斤燃料，
07:43
and those were seven nerve-wracking
hours, because in 2007,
hours, because in 2007,
139
451622
3950
這7小時令人心驚膽戰，因為在2007年，
07:47
there was a leak in the system
of the propulsion of Rosetta,
of the propulsion of Rosetta,
140
455572
3190
羅塞塔號的推進系統出現了漏氣現象，
07:50
and we had to close off a branch,
141
458762
2147
使得我們必須關掉一處分路，
07:52
so the system was actually
operating at a pressure
operating at a pressure
142
460909
2578
因此推進系統實際所處的工作壓力
07:55
which it was never designed
or qualified for.
or qualified for.
143
463487
3298
並不符合原始設計條件。
07:59
Then we got in the vicinity of the comet,
and these were the first pictures we saw.
and these were the first pictures we saw.
144
467795
4909
然後我們到達這顆彗星的附近，
這是我們看到的第一批照片。
這是我們看到的第一批照片。
08:04
The true comet rotation period
is 12 and a half hours,
is 12 and a half hours,
145
472704
2573
這顆彗星真實的自轉週期是12.5小时，
08:07
so this is accelerated,
146
475277
2089
所以這是加快影片，
08:09
but you will understand that
our flight dynamics engineers thought,
our flight dynamics engineers thought,
147
477366
3251
但是你會理解我們的飛行動力學工程師在想什麼，
08:12
this is not going to be
an easy thing to land on.
an easy thing to land on.
148
480617
3854
這可不是一個容易登陸的東西。
08:16
We had hoped for some kind
of spud-like thing
of spud-like thing
149
484471
4644
我們原本希望它像某種馬鈴薯形狀一樣
08:21
where you could easily land.
150
489115
2166
可以輕易的登陸在上面。
08:23
But we had one hope: maybe it was smooth.
151
491281
3291
我們還有一種希望：也許它是平坦的。
08:26
No. That didn't work either. (Laughter)
152
494572
3738
不，以上兩種都不是。（笑聲）
08:30
So at that point in time,
it was clearly unavoidable:
it was clearly unavoidable:
153
498310
2693
因此，當下顯然別無選擇：
08:33
we had to map this body
in all the detail you could get,
in all the detail you could get,
154
501003
3531
我們得儘可能詳細繪製這個天體的地圖，
08:36
because we had to find an area
which is 500 meters in diameter and flat.
which is 500 meters in diameter and flat.
155
504534
5153
因為我們必須找到一塊直徑500公尺的平地。
08:41
Why 500 meters? That's the error
we have on landing the probe.
we have on landing the probe.
156
509687
4599
為什麼是500公尺？
這是我們探測器登陸時的誤差。
這是我們探測器登陸時的誤差。
08:46
So we went through this process,
and we mapped the comet.
and we mapped the comet.
157
514286
3181
我們經歷此過程，繪製出彗星表面的地圖。
08:49
We used a technique
called photoclinometry.
called photoclinometry.
158
517467
2367
我們使用一種叫做照相測斜術的技術。
08:51
You use shadows thrown by the sun.
159
519834
2230
作法是利用太陽拋下的陰影。
08:54
What you see here is a rock
sitting on the surface of the comet,
sitting on the surface of the comet,
160
522064
3087
你在這裡看到一塊安坐於彗星表面的岩石，
08:57
and the sun shines from above.
161
525151
2926
陽光從上面照下來。
09:00
From the shadow, we, with our brain,
162
528077
2159
透過陰影，我們用大腦，
09:02
can immediately determine
roughly what the shape of that rock is.
roughly what the shape of that rock is.
163
530236
3644
可以立刻大致判斷出這塊岩石的形狀。
09:05
You can program that in a computer,
164
533880
2042
這過程可以用電腦寫成程式，
09:07
you then cover the whole comet,
and you can map the comet.
and you can map the comet.
165
535922
4254
然後將範圍涵蓋整顆彗星，
你就可以繪製彗星地圖。
你就可以繪製彗星地圖。
09:12
For that, we flew special trajectories
starting in August.
starting in August.
166
540176
3680
為此，我們從8月份開始以一種特殊的軌跡飛行。
09:15
First, a triangle
of 100 kilometers on a side
of 100 kilometers on a side
167
543856
2909
首先，在100公里距離的地方，
09:18
at 100 kilometers' distance,
168
546765
1663
沿一個邊長為100公里的三角形飛行，
09:20
and we repeated the whole
thing at 50 kilometers.
thing at 50 kilometers.
169
548428
3004
然後將距離及邊長改為50公里再重複整個過程。
09:23
At that time, we had seen the comet
at all kinds of angles,
at all kinds of angles,
170
551432
3647
此時，我們已從各種角度觀察過這顆彗星，
09:27
and we could use this technique
to map the whole thing.
to map the whole thing.
171
555079
4673
可利用本技術繪製彗星全圖。
09:31
Now, this led to a selection
of landing sites.
of landing sites.
172
559752
3267
現在，到了選擇登陸地點的時候了。
09:35
This whole process we had to do,
to go from the mapping of the comet
to go from the mapping of the comet
173
563019
4260
這整個必要過程，從繪製彗星地圖，
09:39
to actually finding
the final landing site, was 60 days.
the final landing site, was 60 days.
174
567279
3565
到實際找到最終登陸地點，花費60天。
09:42
We didn't have more.
175
570844
1386
我們並沒有更多的時間。
09:44
To give you an idea,
the average Mars mission
the average Mars mission
176
572230
2120
給你們一個參考，平均一次火星任務
09:46
takes hundreds of scientists
for years to meet
for years to meet
177
574350
3784
需要上百位科學家花數年的時間開會
09:50
about where shall we go?
178
578134
2067
才能找到一個登陸地點。
09:52
We had 60 days, and that was it.
179
580201
2158
我們只有60天，就那麼多了。
09:54
We finally selected the final landing site
180
582359
3043
我們最終選定了一個登陸點，
09:57
and the commands were prepared
for Rosetta to launch Philae.
for Rosetta to launch Philae.
181
585402
5053
並且為羅塞塔號準備好發射菲萊號的指令。
10:02
The way this works is that Rosetta
has to be at the right point in space,
has to be at the right point in space,
182
590455
4375
其登陸方式為羅塞塔號得處在太空中的正確位置，
10:06
and aiming towards the comet,
because the lander is passive.
because the lander is passive.
183
594830
2823
並且瞄準這顆彗星，因為登陸器是被動的。
10:09
The lander is then pushed out
and moves towards the comet.
and moves towards the comet.
184
597653
3677
隨後推出登陸器，使其飛向彗星。
10:13
Rosetta had to turn around
185
601330
1790
羅塞塔號得轉個身，
10:15
to get its cameras to actually look
at Philae while it was departing
at Philae while it was departing
186
603120
4557
讓其相機正對著菲萊號飛離過程，
10:19
and to be able to communicate with it.
187
607677
2469
及維持通訊。
10:22
Now, the landing duration
of the whole trajectory was seven hours.
of the whole trajectory was seven hours.
188
610146
4574
整個登陸過程花費7個小時。
10:26
Now do a simple calculation:
189
614720
2787
簡單的計算一下：
10:29
if the velocity of Rosetta is off
by one centimeter per second,
by one centimeter per second,
190
617507
4039
如果羅塞塔號的速度誤差是每秒1公分，
10:33
seven hours is 25,000 seconds.
191
621546
4342
7個小時就是25000秒，
10:37
That means 252 meters wrong on the comet.
192
625888
4365
那就意味著登陸器登陸彗星時的誤差是252公尺。
10:42
So we had to know the velocity of Rosetta
193
630253
3344
因此羅塞塔號的速度誤差
10:45
much better than
one centimeter per second,
one centimeter per second,
194
633597
2507
必須小於每秒1公分，
10:48
and its location in space
better than 100 meters
better than 100 meters
195
636104
4064
其太空中的位置誤差必須小於100公尺
10:52
at 500 million kilometers from Earth.
196
640168
3204
此時它距離地球5億公里遠。
10:55
That's no mean feat.
197
643372
2368
那可不容易。
10:57
Let me quickly take you through
some of the science and the instruments.
some of the science and the instruments.
198
645740
4389
讓我快速帶領大家認識一些科學和儀器。
11:02
I won't bore you with all the details
of all the instruments,
of all the instruments,
199
650129
3436
我不會講太多儀器細節，以免大家厭煩，
11:05
but it's got everything.
200
653565
1649
但是它什麼東西都有。
11:07
We can sniff gas,
we can measure dust particles,
we can measure dust particles,
201
655214
3134
我們可以聞氣體，可以測塵粒，
11:10
the shape of them, the composition,
202
658348
2252
測量其形狀及成份，
11:12
there are magnetometers, everything.
203
660600
2508
有磁力儀，等等一切。
11:15
This is one of the results from
an instrument which measures gas density
an instrument which measures gas density
204
663108
3599
這是一部儀器所測到的氣體密度結果
11:18
at the position of Rosetta,
205
666707
1858
位置在羅塞塔號附近，
11:20
so it's gas which has left the comet.
206
668565
2229
所以這是從彗星上釋放出來的氣體。
11:22
The bottom graph
is September of last year.
is September of last year.
207
670794
2484
這下面的圖是去年9月份的結果。
11:25
There is a long-term variation,
which in itself is not surprising,
which in itself is not surprising,
208
673278
3297
可看到一個長期的變化，這變化本身並不稀奇，
11:28
but you see the sharp peaks.
209
676575
1881
但是你看那些尖峰。
11:30
This is a comet day.
210
678456
2090
這就是彗星上的一天。
11:32
You can see the effect of the sun
on the evaporation of gas
on the evaporation of gas
211
680546
4110
你可以看到太陽影響氣體蒸發的效果，
11:36
and the fact that the comet is rotating.
212
684656
2948
以及彗星本身旋轉的事實。
11:39
So there is one spot, apparently,
213
687604
1708
所以顯然有一處地點，
11:41
where there is a lot of stuff coming from,
214
689312
2147
很多東西都出自那裡，
11:43
it gets heated in the Sun,
and then cools down on the back side.
and then cools down on the back side.
215
691459
3297
它受太陽加熱，然後在背面冷卻。
11:46
And we can see
the density variations of this.
the density variations of this.
216
694756
3506
我們可以看看這裡的密度差異。
11:50
These are the gases
and the organic compounds
and the organic compounds
217
698262
4133
這些是我們已經測量到的
11:54
that we already have measured.
218
702395
1695
氣體和有機化合物。
11:56
You will see it's an impressive list,
219
704090
1788
這是一張令人印象深刻的清單，
11:57
and there is much, much,
much more to come,
much more to come,
220
705878
2484
以後還會有更多更多的東西出現在上面，
12:00
because there are more measurements.
221
708362
1946
因為還會作更多測量。
12:02
Actually, there is a conference
going on in Houston at the moment
going on in Houston at the moment
222
710308
3348
其實，目前在休斯頓那邊就有一場研討會，
12:05
where many of these results are presented.
223
713656
2461
許多結果正在發表。
12:08
Also, we measured dust particles.
224
716827
1621
還有，我們也測量塵粒。
12:10
Now, for you, this will not
look very impressive,
look very impressive,
225
718448
2802
現在對你們來說可能毫不起眼，
12:13
but the scientists were thrilled
when they saw this.
when they saw this.
226
721250
3273
但是當科學家們看到這個的時候都非常激動。
12:16
Two dust particles:
227
724523
1417
畫面有兩顆塵粒：
12:17
the right one they call Boris,
and they shot it with tantalum
and they shot it with tantalum
228
725940
2994
右邊的塵粒它們叫伯里斯，他們用鉭去撞擊它，
12:20
in order to be able to analyze it.
229
728934
2114
以便能夠分析它。
12:23
Now, we found sodium and magnesium.
230
731048
2391
我們發現了鈉和鎂。
12:25
What this tells you is this is
the concentration of these two materials
the concentration of these two materials
231
733439
4249
這顯示出太陽系形成時期，
12:29
at the time the solar system was formed,
232
737688
2716
這兩種物質的濃度。
12:32
so we learned things about
which materials were there
which materials were there
233
740404
3367
所以我們學到行星形成時，
12:35
when the planet was made.
234
743771
3088
存在哪些物質。
12:38
Of course, one of the important
elements is the imaging.
elements is the imaging.
235
746859
2718
當然，重要設備之一就是相機。
12:41
This is one of the cameras of Rosetta,
the OSIRIS camera,
the OSIRIS camera,
236
749577
3366
這是羅塞塔號上的一部相機——OSIRIS
(光學、光譜與紅外遙測攝影系統)
相機——所拍攝，
(光學、光譜與紅外遙測攝影系統)
相機——所拍攝，
12:44
and this actually was the cover
of Science magazine
of Science magazine
237
752943
2995
其實這曾是《科學》雜誌
12:47
on January 23 of this year.
238
755938
2670
今年1月23日那一期的封面。
12:50
Nobody had expected
this body to look like this.
this body to look like this.
239
758608
3438
沒有人想到這天體會看來如此。
12:54
Boulders, rocks -- if anything, it looks
more like the Half Dome in Yosemite
more like the Half Dome in Yosemite
240
762046
3598
大卵石，岩石——如果非要和其他地方作比較，
12:57
than anything else.
241
765644
2507
它看起來更像是優勝美地的半圓丘。
13:00
We also saw things like this:
242
768151
2578
我們還看到了這樣的東西：
13:02
dunes, and what look to be,
on the righthand side, wind-blown shadows.
on the righthand side, wind-blown shadows.
243
770729
4922
沙丘，及右手邊，
看起來好像受風吹動的影子。
看起來好像受風吹動的影子。
13:07
Now we know these from Mars,
but this comet doesn't have an atmosphere,
but this comet doesn't have an atmosphere,
244
775651
3924
目前我們知道火星上有這些，但是這顆彗星沒有大氣，
13:11
so it's a bit difficult to create
a wind-blown shadow.
a wind-blown shadow.
245
779575
2879
所以要產生一個受風吹動的影子是有點困難的。
13:14
It may be local outgassing,
246
782454
1985
這可能是局部氣體釋放，
13:16
stuff which goes up and comes back.
247
784439
2183
有什麼東西上升然後落下來。
13:18
We don't know, so there is
a lot to investigate.
a lot to investigate.
248
786622
3181
我們還不清楚，所以還有很多需要調查。
13:21
Here, you see the same image twice.
249
789803
2090
這裡，你看到同一地點的兩張照片。
13:23
On the left-hand side,
you see in the middle a pit.
you see in the middle a pit.
250
791893
2517
左手邊這張，你看中間有一個坑。
13:26
On the right-hand side,
if you carefully look,
if you carefully look,
251
794410
2217
右手邊這張，如果你仔細看，
13:28
there are three jets coming out
of the bottom of that pit.
of the bottom of that pit.
252
796627
3231
有三股氣流從那個坑的底部噴出。
13:31
So this is the activity of the comet.
253
799858
2297
這就是這顆彗星的活動。
13:34
Apparently, at the bottom of these pits
is where the active regions are,
is where the active regions are,
254
802155
4017
顯然，這些坑的底部就是活動區域，
13:38
and where the material
evaporates into space.
evaporates into space.
255
806172
2763
也是物質蒸發到太空的地方。
13:40
There is a very intriguing crack
in the neck of the comet.
in the neck of the comet.
256
808935
3610
這顆彗星的頸部有一條非常引人好奇的裂縫。
13:44
You see it on the right-hand side.
257
812545
1996
你可以從右手邊照片看到。
13:46
It's a kilometer long,
and it's two and a half meters wide.
and it's two and a half meters wide.
258
814541
3696
它有1公里長，2.5公尺寬。
13:50
Some people suggest that actually,
259
818237
2246
事實上有些人暗示，
13:52
when we get close to the sun,
260
820483
2068
隨著我們靠近太陽，
13:54
the comet may split in two,
261
822551
1858
這顆彗星可能一分為二，
13:56
and then we'll have to choose,
262
824409
1680
這時我們將必須選擇，
13:58
which comet do we go for?
263
826089
2252
究竟要跟隨哪一半彗星？
14:00
The lander -- again, lots of instruments,
264
828341
3173
這是（菲萊號）登陸器——一樣的，攜帶了很多儀器，
14:03
mostly comparable except for the things
which hammer in the ground and drill, etc.
which hammer in the ground and drill, etc.
265
831514
5341
除了地面錘子和鑽子等，幾乎可與羅塞塔號相媲美。
14:08
But much the same as Rosetta, and that is
because you want to compare
because you want to compare
266
836855
3877
而與羅塞塔號攜帶幾乎一樣的儀器是因為我們想比較
14:12
what you find in space
with what you find on the comet.
with what you find on the comet.
267
840732
3506
來自太空和來自彗星上的兩種觀察結果有何不同。
14:16
These are called
ground truth measurements.
ground truth measurements.
268
844238
2693
這些稱為“地面真值調查”。
14:18
These are the landing descent images
269
846931
3231
這些是登陸下降照片
14:22
that were taken by the OSIRIS camera.
270
850162
2048
由OSIRIS相機拍攝。
14:24
You see the lander getting further
and further away from Rosetta.
and further away from Rosetta.
271
852210
4226
你看登陸器離羅塞塔號越來越遠。
14:28
On the top right, you see an image
taken at 60 meters by the lander,
taken at 60 meters by the lander,
272
856436
3808
右上角，是登陸器在60公尺高拍的照片，
14:32
60 meters above the surface of the comet.
273
860244
2856
彗星表面60公尺上空。
14:35
The boulder there is some 10 meters.
274
863100
2414
那個大卵石直徑約10米。
14:37
So this is one of the last images we took
before we landed on the comet.
before we landed on the comet.
275
865514
4714
這是我們登陸彗星前所拍的最後一張照片。
14:42
Here, you see the whole sequence again,
but from a different perspective,
but from a different perspective,
276
870228
3558
這裡，我們從一個不同的視角將整個過程再看一遍，
14:45
and you see three blown-ups
from the bottom-left to the middle
from the bottom-left to the middle
277
873786
4185
從圖左下角到中間有三幅放大照，
14:49
of the lander traveling
over the surface of the comet.
over the surface of the comet.
278
877971
4185
顯示登陸器飛過彗星表面的情景。
14:54
Then, at the top, there is a before
and an after image of the landing.
and an after image of the landing.
279
882156
4186
然後，在頂部有登陸之前和登陸之後的對比照片。
14:58
The only problem with the after image is,
there is no lander.
there is no lander.
280
886342
3927
其中，登陸後的照片有個問題就是找不到登陸器。
15:02
But if you carefully look
at the right-hand side of this image,
at the right-hand side of this image,
281
890269
3271
但是你如果仔細觀察這張照片的右手邊，
15:05
we saw the lander still there,
but it had bounced.
but it had bounced.
282
893540
4029
我們看到登陸器還在，只是它彈走了。
15:09
It had departed again.
283
897569
1661
它又離開了彗星表面。
15:11
Now, on a bit of a comical note here
284
899230
3087
現在，有點滑稽的是
15:14
is that originally Rosetta was designed
to have a lander which would bounce.
to have a lander which would bounce.
285
902317
4620
本來在羅塞塔號的設計中，
它會攜帶一個能反彈的登陸器。
它會攜帶一個能反彈的登陸器。
15:18
That was discarded because
it was way too expensive.
it was way too expensive.
286
906937
2573
但是因為成本太高所以這一方案遭捨棄。
15:21
Now, we forgot, but the lander knew.
287
909510
2274
現在，我們忘了這件事，但是登陸器還記得。
15:23
(Laughter)
288
911784
1604
（笑聲）
15:25
During the first bounce,
in the magnetometers,
in the magnetometers,
289
913388
2507
第一次反彈期間，在磁力儀上，
15:27
you see here the data from them,
from the three axes, x, y and z.
from the three axes, x, y and z.
290
915895
3830
你可以看到來自X、Y、Z三個座標軸的資料。
15:31
Halfway through, you see a red line.
291
919725
2206
半途中，你可以看到一條紅線。
15:33
At that red line, there is a change.
292
921931
1834
在紅線處，有發生改變。
15:35
What happened, apparently,
is during the first bounce,
is during the first bounce,
293
923765
3925
發生了什麼？很顯然在第一次反彈時
15:39
somewhere, we hit the edge of a crater
with one of the legs of the lander,
with one of the legs of the lander,
294
927690
4726
登陸器的一條腿在某處碰到一個坑的邊緣，
而登陸器的旋轉速度產生改變。
15:44
and the rotation velocity
of the lander changed.
of the lander changed.
295
932416
2820
15:47
So we've been rather lucky
296
935236
1973
所以我們能落在目前所在位置，
15:49
that we are where we are.
297
937209
2276
是非常幸運的。
15:51
This is one of
the iconic images of Rosetta.
the iconic images of Rosetta.
298
939485
3669
這是羅塞塔號拍的標誌性圖片之一。
15:55
It's a man-made object,
a leg of the lander,
a leg of the lander,
299
943154
3923
那是一個人造物體，登陸器的腿，
15:59
standing on a comet.
300
947077
1951
站在一顆彗星上。
16:01
This, for me, is one of the very best
images of space science I have ever seen.
images of space science I have ever seen.
301
949028
5131
對我來說，這是所見太空科學照片中最棒的一張。
16:06
(Applause)
302
954159
5181
（掌聲）
16:11
One of the things we still have to do
is to actually find the lander.
is to actually find the lander.
303
959340
3851
我們仍然需要去做的一件事是實際找到這個登陸器。
16:15
The blue area here
is where we know it must be.
is where we know it must be.
304
963191
3696
藍色區域是我們認為它應在的位置。
16:18
We haven't been able to find it yet,
but the search is continuing,
but the search is continuing,
305
966887
3618
我們還沒能找到它，但是搜索仍在繼續，
16:22
as are our efforts to start getting
the lander to work again.
the lander to work again.
306
970505
3765
同時我們也在努力讓登陸器重新工作。
16:26
We listen every day,
307
974270
1742
我們每天用心監聽，
16:28
and we hope that between now
and somewhere in April,
and somewhere in April,
308
976012
2558
我們希望從現在到4月份的某個時候，
16:30
the lander will wake up again.
309
978570
1738
這個登陸器會再一次醒來。
16:32
The findings of what
we found on the comet:
we found on the comet:
310
980308
2137
我們在這顆彗星上的發現有：
16:35
This thing would float in water.
311
983795
2456
這個東西可以在水上漂浮。
16:38
It's half the density of water.
312
986251
2624
其密度為水的一半。
16:40
So it looks like
a very big rock, but it's not.
a very big rock, but it's not.
313
988875
3018
因此它看起來雖然像一個很大的岩石，
但實際上不是。
但實際上不是。
16:43
The activity increase we saw
in June, July, August last year
in June, July, August last year
314
991893
3646
去年6、7、8月我們看到
16:47
was a four-fold activity increase.
315
995539
2391
其活躍性提高了4倍。
16:49
By the time we will be at the sun,
316
997930
1743
當我們靠近太陽時，
16:51
there will be 100 kilos
a second leaving this comet:
a second leaving this comet:
317
999673
4573
每秒將會有100公斤的物質離開這顆彗星：
16:56
gas, dust, whatever.
318
1004246
1556
氣體、灰塵等。
16:57
That's 100 million kilos a day.
319
1005802
2531
1天的話就是1億公斤。
17:01
Then, finally, the landing day.
320
1009603
2375
最後，結束前，要提登陸那一天。
17:03
I will never forget -- absolute madness,
250 TV crews in Germany.
250 TV crews in Germany.
321
1011978
5388
我將永生難忘——太瘋狂了，
在德國有250名電視臺工作人員在場。
在德國有250名電視臺工作人員在場。
17:09
The BBC was interviewing me,
322
1017366
2019
當BBC採訪我時，
17:11
and another TV crew
who was following me all day
who was following me all day
323
1019385
2972
旁邊還有一位電視臺工作人員，整天跟著我，
17:14
were filming me being interviewed,
324
1022357
2136
也同時在拍攝我的訪問過程，
17:16
and it went on like that
for the whole day.
for the whole day.
325
1024493
2438
那種狀況持續了一整天。
17:18
The Discovery Channel crew
326
1026931
1811
探索頻道的工作人員
17:20
actually caught me
when leaving the control room,
when leaving the control room,
327
1028742
2322
在離開控制室時找到了我，
17:23
and they asked the right question,
328
1031064
2113
他們問了個好問題，
17:25
and man, I got into tears,
and I still feel this.
and I still feel this.
329
1033177
3625
我竟哭了起來，我現在仍然能感受到這心情。
17:28
For a month and a half,
330
1036802
1683
此後的1個半月裡，
17:30
I couldn't think about
landing day without crying,
landing day without crying,
331
1038485
2834
每次想到登陸日我都會熱淚盈眶，
17:33
and I still have the emotion in me.
332
1041319
2715
那種情緒仍留存在我心裡。
17:36
With this image of the comet,
I would like to leave you.
I would like to leave you.
333
1044034
2949
我想用這張彗星照片來結束今天的演講。
17:38
Thank you.
334
1046983
2113
謝謝。
17:41
(Applause)
335
1049096
4879
（掌聲）
ABOUT THE SPEAKER
Fred Jansen - Space explorerAs manager of the Rosetta mission, Fred Jansen is in charge of the project that could be instrumental in uncovering clues to the origins of life on Earth.
Why you should listen
Fred Jansen manages the European Space Agency’s Rosetta mission, which guided a probe into orbit around a comet and dispatched a lander to its surface -- both firsts in space exploration. Although the lander Philae could not accomplish its full mission before going into hibernation, the data it’s already gathered will immeasurably multiply our knowledge of comets and their contributions to the ingredients of life on Earth.
In addition to his work with the Rosetta Mission, Jansen oversees the ESA’s XMM-Newton, an orbiting x-ray space observatory delving into the most elusive secrets of the universe, including black holes and dark matter.
Fred Jansen | Speaker | TED.com