Comet probe sends back science treasure in final hours

November 15, 2014 by Richard Ingham, Veronique Martinache
A photo released on November 13, 2014 by the European Space Agency, and captured on November 12 by the CIVA-P imaging system, shows a 360º view of the surface of comet 67P/Churyumov-Gerasimenko during Philae's descent

Europe's science probe Philae sent home a treasure trove of data from a comet heading towards the Sun before falling silent as its power ran out, mission control said Saturday.

Crowning a historic feat, the robot lab streamed data from its experiments back to its mother ship Rosetta in the final hours before its battery ran down.

This included the outcome of an eagerly-waited chemistry test of a sample drilled from the comet's icy and dusty surface, scientists said.

"Rosetta's lander has completed its primary science mission," the European Space Agency (ESA) said.

Lacking power, its instruments and most systems went into standby mode after three days of non-stop work, sending back data that will keep scientists busy for years.

"The data collected by Philae and Rosetta is set to make this mission a game-changer in cometary science," said Matt Taylor, Rosetta project scientist.

Philae had landed in a dark shadow after a bouncy triple touchdown Wednesday.

It did not get enough sunlight to recharge its batteries sufficiently to extend its mission beyond its initial 60-hour work programme.

Mission engineers do not rule out making contact with the lander in the coming months as Comet 67P/Churyumov-Gerasimenko moves closer to the Sun.

Conceived more than 20 years ago, the Rosetta mission aims at shedding light on the origins of the Solar System 4.6 billion years ago, and maybe even life on Earth.

A graphic shows the difficult landing of Philae on 67P

A theory gaining ground in astrophysics is that the fledgling Earth was pounded by these bodies of cosmic ice and carbon-rich dust, seeding our planet with the basics to start life.

Rosetta and its payload travelled more than six billion kilometres (3.75 billion miles), racing around the inner Solar System before they caught up with the comet in August this year.

On Wednesday, Philae bade farewell to its mother ship and descended to a comet travelling at 18 kilometres (11 miles) per second, 510 million kilometres (320 million miles) from Earth.

The touchdown did not go entirely as planned—hardly a surprise in an operation some gloomily predicted had only a one-in-two chance of success.

Philae landed smack in the middle of its targeted site, but a pair of anchoring harpoons failed to deploy.

It rebounded, touched down again, bounced up once more and then landed for the third time at a place believed to be about a kilometre (half a mile) from the landing site.

Philae found itself in the shadow of a cliff, tilted at an angle that left one of its three legs pointed to the sky.

Weighing 100 kilos (220 pounds) on Earth, Philae's weight is just one gramme (0.03 of an ounce)—less than a feather—on the low-gravity, four-kilometre comet.

That meant just a jolt could have caused it to drift off into space.

And lack of sunlight for its solar panels meant it had to survive on a battery with a charge of around 60 hours, enough to carry out its scheduled scientific work.

Race against time

Stacked against the odds, the scientists resorted to every trick possible to use power miserly and keep Rosetta working without causing it to drift away.

Using the lander's toolkit of 10 instruments, they started with passive observation—taking pictures, measuring the comet's density, temperature, and internal structure, "sniffing" molecules of gas from its surface—that would not move the craft.

Finally, in the most important but riskiest experiment of all, they drilled a core of material out of the comet surface to analyse its chemical signature.

All the data had to be stored and dispatched back to Rosetta as the power indicators shrank towards the red zone.

"We received everything," mission scientist Jean-Pierre Bibring told AFP. "The word is 'fabulous,' just 'fabulous.'

The team's eagerly-awaited first report will be made at a meeting of the American Geophysical Union (AGU) in San Francisco next month.

The "67P" comet is due to loop around the Sun next year, flaring gas from its head and leaving a spectacular icy trail of ice from water stripped from its surface.

Rosetta will escort it until the heads back out towards the depths of the Solar System in December 2015.

Explore further: Relief as signal arrives from comet lander

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31 comments

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billpress11
5 / 5 (3) Nov 15, 2014
Quote from article: "Weighing 100 kilos (220 pounds) on Earth, Philae has a mass of just one gramme (0.03 of an ounce)—less than a feather—on the low-gravity, four-kilometre comet."

That should be weighing 0.03 of an ounce and has a mass of 220 pounds.
douglaskostyk
5 / 5 (4) Nov 15, 2014
" Weighing 100 kilos (220 pounds) on Earth, Philae has a mass of just one gramme (0.03 of an ounce)—less than a feather—on the low-gravity, four-kilometre comet. "

weight and mass, all mixed up in this statement. Philae is still 100 kg, it just has less weight.
TheGhostofOtto1923
1 / 5 (1) Nov 15, 2014
I suppose they'll have to consider some sort of harpoon they can shoot into the surface and pull the probe down into contact.
TheGhostofOtto1923
1 / 5 (1) Nov 15, 2014
You know, like the US is working on.
http://m.space.com/13948-nasa-comet-harpoon.html
thouser98
2 / 5 (2) Nov 15, 2014
I read the headline, "...send back science treasure.....," but there was none listed in the article. Really? Come on man!
UzzaBeeNet
1 / 5 (5) Nov 15, 2014
The primary problem was the use of the word "landing". Had the mindset of the engineers been that Philae needed to "dock" with the comet, then perhaps they would have slowed the speed down to much less than 1m/s. Also, they should have considered that the anchor harpoon may fail to fire. A softer "docking" would have least assured that Philae was on the surface, even if it couldn't be anchored. There is no excuse for failing to take these factors into account and causing an initial bounce lasting almost 2 hours! They're lucky they got any data at all.
JimD
1.6 / 5 (7) Nov 15, 2014
Someone should've thought about the likelihood that the probe would not land on a flat spot with adequate sunlight. Wow! Bumbling incompetence.
whiffledust
4.6 / 5 (9) Nov 15, 2014
Seems some posters fail to realize that it took 10 years and 3 close encounter type course corrections to even get to the point of making an attempted landing upon the comet in the first place. I wonder how many naysayers were even adults at the time this mission started, as appears to me not many were otherwise they would have had abit more enthusiasm for the fact that decades of time and hundreds of millions of miles later the lander actually made the objective. I'm impressed that those who undertook the project, against all the odds succeeded and should be congratulated, not criticized.
dharper7
3.7 / 5 (3) Nov 15, 2014
The primary problem was the use of the word "landing". Had the mindset of the engineers been that Philae needed to "dock" with the comet, then perhaps they would have slowed the speed down to much less than 1m/s. Also, they should have considered that the anchor harpoon may fail to fire. A softer "docking" would have least assured that Philae was on the surface, even if it couldn't be anchored. There is no excuse for failing to take these factors into account and causing an initial bounce lasting almost 2 hours! They're lucky they got any data at all.


Thank Captain Hindsight. Maybe you should get a job there and tell those genius scientists whats up!!
SFmike
1 / 5 (4) Nov 15, 2014
Pity. All that work, all those miles, and let down by relying on solar panels in the shade.

The Law of Unintended Consequences strikes again.
UzzaBeeNet
2.8 / 5 (4) Nov 15, 2014
Really@dharper7? To understand the gravity of this sized comet vs mass of Philea, and to think about the consequences of a failure of one or more systems on your probe is not hindsight, it's forethought; that's what systems engineers are suppose to be thinking about. They must brainstorm all possible scenarios and design the systems to mitigate risk. Actually though, they probably thought of that. The only reason they hit so hard was they must have underestimated the density of the Churyumov-Germasimenko's, which caused their "landing" speed to exceed the design limitations. That, and the anchor harpoons failing to deploy relegated this mission to just a nominal success. I would love to see the final mission report.
s2zeller
1.3 / 5 (4) Nov 15, 2014
Is there some reason a longer-lasting battery (e.g. nuclear, or at least multiples of the lithium-based for redundancy) wasn't put on board?

Granted, the actual implementation was enough to accomplish the initial mission, but what if that had failed?

I'm not trying to second-guess the team that put this awesome endeavor together (at least not much), but it seems like it would have been a likely scenario to have planned for.
TheFreudianSlip
1 / 5 (1) Nov 15, 2014
Perhaps a velcro like ball would have functioned better. Next time will be better. Kudos to the team, great effort.
Vietvet
4.3 / 5 (6) Nov 15, 2014
"The only reason they hit so hard was they must have underestimated the density of the Churyumov-Germasimenko's, which caused their "landing" speed to exceed the design limitations."

It landed at the designed speed. They knew the thrusters weren't going to work and it would be risky relying on the anchors without the thrusters. But what are you going to do after traveling through space for ten years, just throw up your hands and say "forgeta about it"?

Vietvet
3.3 / 5 (3) Nov 15, 2014
For a little perspective.

https://www.faceb...;theater
SSDeath Basturd
1.7 / 5 (6) Nov 15, 2014
There is no sun in Germany either and lots of worthless solar panels, just like on this lander.

Guess the Greens doomed this mission before it started.

Harpoons and solar power didn't work, mission is a complete success!
renken
1.6 / 5 (7) Nov 15, 2014
Boy I but the homeless and hungry really think this money spent by government funded scientists really improves their life....
mooster75
2.3 / 5 (3) Nov 16, 2014
There is no sun in Germany

That explains a few things...
bobderek
3 / 5 (2) Nov 16, 2014
The weight of an object varies as gravity varies. The mass of an object is constant. Pounds are a measure of weight, kilograms a measure of mass. So the weight of that 200 pound earth weight object will move lower as gravity decreases. However, that object will have a mass of about 90kg 718.47g no matter what the gravity is. Mass, the "amount" of an object, never changes.
Doug_Huffman
5 / 5 (1) Nov 16, 2014
Mass, the "amount" of an object, ...
Ya did fine until here. The unit of amount is Mole = Avogadro's Number of things.
tilaran
1.8 / 5 (5) Nov 16, 2014
Will take years for scientists to analyze.Hmmmmm. The last mineral, dirt and water samples I had done took less than a week.
Anyone smell"grant money" here ?
EnricM
5 / 5 (2) Nov 16, 2014
I suppose they'll have to consider some sort of harpoon they can shoot into the surface and pull the probe down into contact.


There was indeed a harpoon. It wasn't fired because there was an issue with a little trusted on the top of the probe that was meant to neutralize the momentum provided by the harpoon. Seems to have been a problem with the removal of a seal that covered the thruster.

EnricM
not rated yet Nov 16, 2014
There is no sun in Germany

That explains a few things...

Bwahaaaa, we stole it and hid it in Scheveningen, they will never get it back as they are unable to correctly spell the name XD
blisteryhistory
3 / 5 (4) Nov 16, 2014
This socialist space exploration plan only looks good on paper.
tomrb
1 / 5 (5) Nov 16, 2014
I say again why did they not just land anywhere gather up some Rockies and put in there basket ride asteroid back close the earth jump off into orbit and have Russia or china pick up there Rockies. and as far as power Duracell's last a long time. stupid idiots gosh
tomrb
1 / 5 (5) Nov 16, 2014
I say again why did they not just land anywhere gather up some Rockies and put in there basket ride asteroid back close the earth jump off into orbit and have Russia or china pick up there Rockies. and as far as power Duracell's last a long time. And why did they not think about gorilla glue they could shot it at landing spot and gripped like a gorilla stupid idiots gosh
Torbjorn_Larsson_OM
5 / 5 (3) Nov 16, 2014
Everyone can wish for a mission extension, but Philae did 100 % of its primary mission. Not bad for a first attempt!

@EnricM: I think the harpoons were commanded to fire, but neither did. Nor did the heater that was supposed to remove a wax seal to the nitrogen thruster. As said before, both harpoons and wax seals are many thousands of years old technologies ... Oh, well.
Torbjorn_Larsson_OM
5 / 5 (5) Nov 16, 2014
@renken: "Boy I but the homeless and hungry really think this money spent by government funded scientists really improves their life...."

I bet they do, but I am surprised you imply you don't think so. Everyone should _know_ that science is among the best ROI markets we have! Even if we can't predict exact which Is will give the Rs, it is all heavily correlated. Not doing science where we can is then a waste. [NASA research on research; google it up.]

E.g. the web alone that we use here is a major economical factor in Africa (more precisely, the phones that go with), they can plan daily work and buy/sell efficiently. Similarly, those homeless can google up the payoff of science nowadays, unless they are dysfunctional they have phones as far as I've seen - all of them, it seems to me. That technology came out of CERN accelerator infrastructure...
Torbjorn_Larsson_OM
5 / 5 (3) Nov 16, 2014
[ctd] Ironically then, not knowing that science is money well spent, comes out of less well spent money (and time) for web traffic of not researching the issue...

[I know, I have to reset the circuit protection for my irony meter yet again. Every time you think you have seen the last of false choice - 'we can't do both because ... just because' - and on science no less, it returns.]
antialias_physorg
5 / 5 (3) Nov 17, 2014
then perhaps they would have slowed the speed down to much less than 1m/s

This would have required multiple thrusters and larger fuel reserves (read weight that would have reduced the scientific payload). Seeing as the one thruster that was supposed to push Philae down failed after all this time in space - what makes you think that 6 (or more) thrusters would have all worked perfectly to get a softer landing? Any more brilliant ideas?
Pity. All that work, all those miles, and let down by relying on solar panels in the shade.

The science got done. So it's a success either way. Any more would have been a bonus (and maybe they'll get more when it gets closer to the sun)

and lots of worthless solar panels

Funny how these 'worthless solar panels' are generating lots of power (pretty envious of my fathers energy bill. The panels paid for themselves after 12 years and from now on it's all savings)
exequus
5 / 5 (1) Nov 24, 2014
What a super-duper achievement, deservedly lauded and celebrated by just about everybody with the exception of JimD and his fellow chauvinists for whom the only game that counts in space exploration is the one played by the U.S.A. The rest of the world? Bumbling incompetents, naturally, even when a mission this complex manages, against astronomical odds, to deliver on its primary objective. I wonder what JimD would say about the NASA rocket that blew up on lift-off a few weeks ago, or the even more tragic crash of the Virgin space plane. Tell us, JimD, are these examples of peerless anglo technology? Stupid a..hole

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