
Philae comet lander wakes up - DangerousPie
http://www.bbc.co.uk/news/science-environment-33126885
======
JohnHammersley
Woo hoo! What amazing news, especially given the difficulties during the
landing.

For those who didn't see the original coverage, you can see some brilliant
photos of the bounce the lander made during it's landing on the comet here:
[http://www.space.com/27788-philae-comet-landing-bounce-
photo...](http://www.space.com/27788-philae-comet-landing-bounce-photos.html)

Also a hat tip to the earlier missions (such as the Beagle probe that was lost
on Mars) which emphasized the importance of retaining radio contact for as
long as possible during landing and being able to send and receive commands
with the minimum amount of hardware reconfiguration once landed.

What a fantastic start to Sunday!

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kartikkumar
Wowoweeeee! This is FANTASTIC news! One of the few times that I have felt like
typing in all caps. Incredible news and a testament to the survivability of
space hardware. It'll be interesting to see how quickly they can triangulate
Philae's true position to better understand the amount of incident light
reaching the solar panels. It'll also be interesting to see how much of the
payload has survived. Any more data would be of huge scientific value!

Definitely made my day! :)

EDIT: fixed typo

~~~
aaggarwal
Yes, amazing news, I am waiting for more data to come in to analyze the comet
surface and the condition of the lander. This is obviously one the biggest
achievement of modern space missions and ESA.

~~~
aidanhs
Also an impressive achievement on the software side of things - no room for
showstopper bugs here! It's not quite as simple as taking it offline,
deploying some new code and starting it up again.

Is there any information on the processes used to have such a high level of
confidence in the software? Lots of simulation? Relatedly, it might also be
interesting to see a list of 'known bugs' and ways they've been worked around.

~~~
aaggarwal
Hmm, I am not sure if they would have very sophisticated software on the
lander, in the way your thinking. I don't think any processing is done on the
lander itself. It might be just primarily used as a remote sensing telemetry
system. I suppose the lander would have a lot of power management circuits,
some control circuits, sensor-actuator circuits, and transmitter-receiver
communication circuitry. There would probably be a RTOS for real-time
measurement and actuator motion.

Still, I think someone with specific expertise might give a better answer.

~~~
Osmium
> Hmm, I am not sure if they would have very sophisticated software on the
> lander, in the way your thinking.

I think it's safe to say that's still an order of magnitude more sophisticated
than anything I deal with on a daily basis ;)

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stbullard
Wow! And XKCD has already updated his epic Landing live-comic:
[https://xkcd.com/1446/](https://xkcd.com/1446/)

(See
[http://www.explainxkcd.com/wiki/index.php/1446:_Landing](http://www.explainxkcd.com/wiki/index.php/1446:_Landing)
for the background)

~~~
bitwize
I'm on a comet! I'm on a comet! Take a good hard look at the motherf*ing
comet!

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aaronharnly
The NYTimes is running a nice collection[1] of the jaw-dropping photos of the
comet from Rosetta over the course of the mission, including some from the
past month, and the spectacular close fly-by in March.

As many faraway and strange places as we've explored in the Solar System so
far, something about this comet – roughly the breadth of Central Park, yet
with untold nooks and crannies – feels more coldly alien than anything else
I've seen.

[1]
[http://www.nytimes.com/interactive/2015/03/20/science/space/...](http://www.nytimes.com/interactive/2015/03/20/science/space/rosetta-
comet-photos.html)

~~~
jxcl
These are fantastic. I want to get them printed and hang them up on my wall.

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CydeWeys
I wish Europe weren't so nuke-averse. The lander should have been powered by a
radioisotope thermoelectric generator (RTG), not solar panels. Then it
would've had uninterrupted power for years and it could have been returning
scientific data continuously since November.

Most of the US's long distance space probes have been powered with RTGs, which
don't put nearly the same kinds of limitations on mission profiles. The New
Horizons mission to Pluto, for example, is powered with 10.9 kg of plutonium
that provides a steady 228 watts and enough heat to prevent the kind of cold-
related damage we fear happened on Philae. That mission is so far from the Sun
that it wouldn't even be possible with only solar panels.

~~~
dempseye
You're blaming this on Europe being nuke averse, but Europe is not a
homogenous area. While some European countries may be nuke averse, others have
adopted nuclear power to a huge extent.

There are other reasons why an RTG might not have been appropriate for Philae.
They're pretty heavy, and the lander is pretty light. Also, it is wasteful to
use an RTG that could last many years when the mission is only expected to
last several months.

~~~
CydeWeys
You're right that Europe isn't homogenous, but it's not like every country in
Europe has its own independent space agency. They have the ESA, which is nuke-
averse. I was using "Europe" as a linguistic short-cut for the European space
efforts, which are unified.

Per someone else's comment, RTGs don't have to be heavy. Wikipedia lists one
as light as 2.1 kg:
[https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_ge...](https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator#Models)
Keep in mind that RTGs replace not just the solar panel and electricity
generating systems but also a lot of the heating system as well.

You can see the breakdown on Philae here:
[https://en.wikipedia.org/wiki/Philae_(spacecraft)#Design](https://en.wikipedia.org/wiki/Philae_\(spacecraft\)#Design)
It uses about 16 kg total between the power system and thermal control system.
You could fit in an RTG with the same or higher power output as the solar
panels for the same mass. Philae in total is around 98 kg, which is definitely
above the size threshold of craft that could be powered with an RTG.

~~~
DasIch
Not every country has it's own but quite a few do, like Germany for example.

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danso
Does anyone have any insight on what the team does while waiting for the
lander to wake up? Or in these past months when it wasn't sure if Philae had
successfully landed? I know in movies the team would be depicted as hunching
over blinking consoles 24/7 and tapping keys furiously until something
happened...but how is the team organized to work in the long haul? Are there a
few scientists and engineers devoted to the operational status of the lander,
while the rest work on examining past data that it has sent? Or they're
working on researching the next prototype lander?

~~~
nerd_stuff
A couple of things come to mind, though I'm speculating.

Operations: Rosetta and Philae are a pair of robots 300 million kilometers
from earth, one on a comet and the other orbiting it. Rosetta's orbits require
a bit of work, if I remember correctly it's not a stable orbit and Rosetta
needs to be within communication range of Philae while Philae is in the
sunlight.

Science: Interpreting data is not easy and probably takes months in many
cases. Once they've come to their conclusions they have to write and publish
their papers which takes time.

Planning: They have to plan what they will do with Philae's future awake time
which is filled with unknowns and opportunities that may only happen once.

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deepnet
With any luck we will have livestream of a comet entering Perihelion from the
surface.

This is potentially the space mission of the Century.

More surface data is going to change what we know about Solar System
formation.

Looks like Philae awoke earlier and has accumulated 8000 data packets for
transmission to Earth, via Rosetta - fingers crossed for more surface photos
later today :D

Coupled with Matt Taylor's seat of the pants trajectories through the tail and
coma, solar panels buffeted by highly turbulent solar wind - this is going to
be a super exciting science adventure.

Now we have located Philae, CONSERT'S volumetric map of the comet interior
will find out the interior structure and hopefully resolve the contact-binary
question.

That is if the tidal forces of Jupiter don't tear 67P apart.

~~~
ginko
>This is potentially the space mission of the Century.

I would really hope it isn't.

~~~
deepnet
space mission of the Century , so far...

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orf
When I'm feeling particularly melancholy I tell myself that none of the apps
I've made are ever going to outlive me, and they really don't matter in the
scheme of things.

But this... this is cool. Someone somewhere has programmed that lander so that
it's able to not only able to locate earth (whilst hurtling through god knows
where on a big rock) but also successfully re-establish communications. Those
developers must be having a good day today, finally seeing their work come to
fruition.

~~~
pja
I believe the lander is communicating via the Rosetta probe which is relaying
its data to earth. (This design meant that Philea needs to dedicate very
little power to radio transmissions.) It’s still awesome though :)

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140am
Great news. The linked BBC video "What is 67P? In 60 seconds" was very
informative as I had little knowledge about 67P :)
[http://emp.bbc.co.uk/emp/embed/smpEmbed.html?playlist=http%3...](http://emp.bbc.co.uk/emp/embed/smpEmbed.html?playlist=http%3A%2F%2Fplaylists.bbc.co.uk%2Fnews%2Fscience-
environment-29996475A%2Fplaylist.sxml&title=Comet%2067P%20explained%20in%2060%20seconds&product=news&lang=en-
gb)

~~~
pimlottc
Nice music, too ;)

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return0

      "In any case, by March 2015, when the comet is closer to the Sun, 
      it is likely that the lander will become too hot to operate. [...] 
      It will next pass through perihelion on 13 August 2015, 
      186 million kilometres from the Sun."

([http://www.esa.int/Our_Activities/Space_Science/Rosetta/Freq...](http://www.esa.int/Our_Activities/Space_Science/Rosetta/Frequently_asked_questions))

Will the heat affect the lander's measurements?

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warmcat
Wow....I just read "The Martian" novel and this reminds me of a scene when the
astronaut uses the dead Pathfinder probe to communicate with Earth.

~~~
LAMike
Awesome book!

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bane
It's awesome to wake up into a day knowing that humanity is taking another
step forward into the boundaries of knowledge.

Absolutely awesome.

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SCAQTony
The first photo looks like a submerged, antique, sculpture of a man looking up
towards the surface. Just beautiful!

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sidcool
Was this intentional hibernation?

~~~
kuschku
Yes and no. The original plan intended that Philae would have power due to
being in the sun, but the lander bounced off of the comet and landed in a
different place then expected, in the shadow of rough terrain.

Due to this the original set of experiments had to be completely run on
battery, although the battery capacity was not intended for this.

So ESA had to hibernate it early, hoping one day it would get enough sunlight
to be able to operate again, and allowing them to do more experiments – which
happened now.

~~~
sidcool
Wow, that's amazing. Hope the lander didn't sustain any damage.

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neals
I really thought the thing was lost when it bounced off a kilomter from the
comet. The main-stream news-coverage (for me) ended in dissapointment. So did
the lander actually fly back after that bounce and savely land on the surface?
Great to hear.

~~~
wbhart
It didn't fly back. It bounced, as in what goes up must (unless it achieves
escape velocity), come back down. The comet has gravity, just like earth. Just
not much, because it is much smaller than earth

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geoffbrown
YESSSSSS!!!!

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saidajigumi
The long-running XKCD comic "Landing" has been updated for the occasion:

[http://xkcd.com/1446/](http://xkcd.com/1446/)

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benihana
Oh my goodness I cannot image the excitement the Philae team must feel at
having their baby phone home. Congratulations! Woohooo!! This is so awesome!

