
Europe's Rosetta probe goes into orbit around comet 67P - NickPollard
http://www.bbc.co.uk/news/science-environment-28659783
======
yread
You can watch the live stream here
[http://rosetta.esa.int/](http://rosetta.esa.int/)

The detailed explanations and behind the scenes looks are really interesting,
meeting such tiny piece of rock 400M km away is just crazy.

Sometimes it's also funny (one of the scientists was showing a slow mo video
with seemingly nothing happening "well, you got time, right? _WE_ had to wait
for 10 years")

EDIT:it's over

~~~
exDM69
> The detailed explanations and behind the scenes looks are really
> interesting, meeting such tiny piece of rock 400M km away is just crazy.

What makes this even more crazy is that the space craft cruised 31 months
powered down, from Mars to beyond the orbit of Jupiter and then back. The
precision required to accomplish this is tiny!

The mission controllers must have had a pretty good confidence before giving
the ok to power down.

Huge accomplishment and magnificent engineering. Hats off to the guys in ESOC
and other ESA facilities.

~~~
levesque
Is the precision tiny or huge? :>

~~~
tormeh
I think "great" is the word. Tiny margins/tolerances, but not precision. Not
that it really matters.

~~~
verytrivial
Even if it doesn't matter: "exquisite".

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Sharlin
I watched ESA's livestream this morning and they explained that Rosetta is
actually just co-orbiting the Sun with 67P as of now. They're making it slowly
drift to a few different directions and measuring the acceleration caused by
the comet's gravity, so they can build an accurate model of the mass and
density distribution of such an irregularly shaped object.

~~~
jeroen94704
With the masses of the comet and the spacecraft being relatively close, it's
hard to tell whether Rosetta is co-orbiting the sun or orbiting the comet
itself.

~~~
exDM69
> With the masses of the comet and the spacecraft being relatively close

No, they're not close at all. The comet is three by five kilometers across,
and the mass is around 3.14 * 10^12 kg. The orbiter at launch weighs in at
2900 kg and the lander is 100 kg.

[http://en.wikipedia.org/wiki/Rosetta_(spacecraft)](http://en.wikipedia.org/wiki/Rosetta_\(spacecraft\))
[http://en.wikipedia.org/wiki/67P/Churyumov%E2%80%93Gerasimen...](http://en.wikipedia.org/wiki/67P/Churyumov%E2%80%93Gerasimenko)

~~~
BtM909
I think jeroen94704 is saying "With the masses of the comet _,_ and the
spacecraft being relatively close"

[comma added]

~~~
dalke
I disagree. At the very least it would need to be "mass" not "masses". The
closest statement should be more like "With the mass of the comet, and the
spacecraft being relatively distant."

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basicallydan
This is my favourite part of the article:

 _The mission gets even more ambitious in November when, after moving Rosetta
closer to 67P, mission controllers will attempt to put the Philae lander on
the surface.

The lander will use harpoons to anchor itself and will carry out a series of
experiments, including drilling into the material that makes up the comet.

The mission aims to add to knowledge of comets and their role in ferrying the
building blocks of life around the early Solar System._

Harpoons. Very, very cool. I can't wait to find out more about this comet!

~~~
arianvanp
And the obligatory XKCD: [http://xkcd.com/1402/](http://xkcd.com/1402/)

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sidcool
I watched the news on BBC. They are right now in an orbit 100 km away from the
comet and getting pictures of 2.5 mt resolution. In the next few weeks they
will reach upto 30 km orbit and take more high resolution pics.

The head of the mission mentioned about boulder like structures on the comet,
origins of which is not knows. The comet also has vast plain areas, suitable
for landing a probe. It will be by November when we get detailed results of
the chemical composition of the comet.

~~~
bergie
Photo of the surface:
[http://www.esa.int/var/esa/storage/images/esa_multimedia/ima...](http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/08/comet_details/14710766-1-eng-
GB/Comet_details_fullwidth.png?1407329750964)

------
base
Photo of the comet:
[https://pbs.twimg.com/media/BuWJaVSIcAAVgZ9.jpg:large](https://pbs.twimg.com/media/BuWJaVSIcAAVgZ9.jpg:large)

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zak_mc_kracken
Video of the approach:

[https://www.youtube.com/watch?v=Emhj53b-YOI](https://www.youtube.com/watch?v=Emhj53b-YOI)

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TomGullen
> On 6 June 2014 water vapor was detected being released from Churyumov-
> Gerasimenko at a rate of roughly 1 litre per second

[http://en.wikipedia.org/wiki/67P/Churyumov%E2%80%93Gerasimen...](http://en.wikipedia.org/wiki/67P/Churyumov%E2%80%93Gerasimenko)

I find that pretty amazing! That's a lot of water coming off one comet just
being sprayed everywhere.

~~~
robin_reala
The comet is pretty big. I don’t know if you know London, but this image
posted on the BBC earlier put it into perspective:
[http://ichef.bbci.co.uk/news/625/media/images/76758000/jpg/_...](http://ichef.bbci.co.uk/news/625/media/images/76758000/jpg/_76758586_rosetta_comet_624.jpg)

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ck2
_The probe weighed in at 3,000kg at liftoff back in 2004, with over half of
that made up of propellant_

Wow I am starting to understand why they are so interested in that propellant-
free drive.

Does the comet actually have enough gravity to make an orbit happen or is the
orbit completely artificial?

~~~
hrjet
My guess: The probe won't orbit the comet, but rather orbit the sun in sync
with the comet. That too would be artificial because the comet's mass and the
probe's mass will keep changing (presumably at different rates). So the probe
would need to catch up every once in a while.

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owenversteeg
That's a great article. The author said "invested" rather than "spent" a
billion euros, I loved the visualization [0] of how big the asteroid was, and
they kept the article not too technical as to bore the audience but technical
enough to interest the more science-minded readers.

[0]
[http://news.bbcimg.co.uk/media/images/76758000/jpg/_76758586...](http://news.bbcimg.co.uk/media/images/76758000/jpg/_76758586_rosetta_comet_624.jpg)

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lotsofmangos
This is the first step in developing the techniques required to sustain life
in space without having to haul everything up Earth's gravity well. If we can
get good at this, then it changes the entire economics of space.

~~~
Narishma
What techniques are you referring to specifically?

~~~
exch
I am guessing OP is referring to the ability to reliably orbit and land on
comets (and asteroids). We can use them for manned way stations or
construction platforms. Not to mention mining them for whatever useful stuff
may be in there.

~~~
XorNot
If we could show that comets have available surface water ice in the right
form, then their gravity is low enough that you could plan to drill it off and
melt it to be fed into water-ion thrusters. That would let you at the very
least launch a mission which could study one comet, refuel, then slingshot
away to a different target.

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soperj
I feel like I'm in a new era where more people care about space again, but the
reality is probably more that the "right" people care about space, so now more
is happening.

~~~
MrRage
When did this era start? This probe was launched 10 years go, and the planning
must have started at least a few years before that.

~~~
soperj
after the 90s.

~~~
MrRage
Hmm so when were was there a lull? Serious question. I grew up in the 80's and
although I don't check space news every day it doesn't seem like activity in
space decreased in that time. All I'm really aware of is the loss in interest
in, say, manned moon missions after Apollo 11. Are you talking about robotic
probes?

~~~
soperj
Maybe it's the fact that I can actually watch all the launches now, and things
are making the news. I'd never hear about the launch of anything in the 90s.
It was all too mundane or routine to even get a note in the paper apparently.

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tegeek
I wish I could upload my brain to something like Rosetta &amp; blast into the
space, travelling around space bodies, planets &amp; glaxies, gather the
information &amp; transmit back to space for the other Rosettas.

What more it'll take to create an artificial intelligent life which can
sustain herself almost everywhere?

~~~
ojilles
Accelerando.

~~~
jarin
For those who don't get the reference, it's a fantastic book by Charles Stross
that you can get for free from his website:

[http://www.antipope.org/charlie/blog-
static/fiction/accelera...](http://www.antipope.org/charlie/blog-
static/fiction/accelerando/accelerando-intro.html)

~~~
ojilles
Thanks for that link, did not know that was freely available! It's a blast to
read.

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Rapzid
This is incredible.

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flibitboat
Wait.. I thought it said the live airing was happening at 13:00 CEST today?!
did I miss it?! NOooo!!

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eps
Rosetta project is incredibly inspiring.

If you are ever stuck trying to name a variable, fire up your browser, look at
Rosetta's trajectory and let the fact that it's a flawlessly-executed ten-year
billion-kilometer plan to catch up with a fleck of rock in space sink in. Then
go back to your coding :)

~~~
incision
_> 'Then go back to your coding...'_

...where you imagine that you actually are working on trajectories - at
Gattaca Aerospace [1].

(Great movie, one of my favorites.)

1:
[http://en.wikipedia.org/wiki/Gattaca](http://en.wikipedia.org/wiki/Gattaca)

------
personZ
I assume that it isn't actually orbiting the comet, but instead is just
adjusting to follow the same orbit as the comet, right?

~~~
arethuza
It's being described as a "triangular orbit" :-)

 _" Rosetta will, follow, at least for now, a three-legged triangular orbit
that requires a small thruster burn at each apex. The legs are about 100 km
long and it will take Rosetta between three and four days to complete each
one."_

[http://blogs.esa.int/rosetta/2014/08/04/whats-happening-
in-r...](http://blogs.esa.int/rosetta/2014/08/04/whats-happening-in-rosetta-
mission-control-today/)

~~~
personZ
What a fascinating, seeming convoluted (but clearly intentional and
purposeful), flight path. Fascinating stuff, and it's amazing it has that much
residual thrust available.

~~~
Sharlin
AFAIK they're only doing it for a while to measure 67P's mass and density
distribution, so they can calculate a "real" orbit for Rosetta later (but it
will still require regular adjustments due to the highly irregular shape of
the comet).

