Philae craft lands on comet

And what if they discover a trace of RNA?

TomS said: And what if they discover a trace of RNA?

ESA has a different structure from NASA’s. It relies much more on contributions from member-states, whereas NASA pays for most instrument development directly. On Rosetta, for example, ESA hasn’t paid for very much of the €100 million camera, called OSIRIS, and therefore has less control over how its data is disseminated. “It’s easier for [NASA] to negotiate [data release] because we’re paying the bills,” Green says, whereas ESA has to do it “by influence.”

Awesome that it made the landing safely! Hope pictures do get released. But one thing I note in the BBC article about it (and have seen elsewhere):

"One theory holds that comets were responsible for delivering water to the planets. Another idea is that they could have "seeded" the Earth
with the chemistry needed to help kick-start life."

I apologize, I am speaking from ignorance, but why should this be the case? Why would there be any greater likelihood that the chemistry or water would exist on a comet, but not on a planet like Earth (billions of years ago etc)?

TomS said: And what if they discover a trace of RNA?

Last fall, my freshman design course was "hired" to design a lander that would automatically right itself if it landed on a slope. The designs in my class included gimbal mounts, eccentrically balanced spheres or spheroids, and a few devices that deployed feet that oriented the device after it landed -- but very, very slowly, so that the lander was not thrown off the asteroid. We were told to assume that the asteroid was not smooth. I was interested that the Philae team located a flat spot and aimed for it; we were never told that was an option.

Unfortunately, according to CNN, the harpoons failed to deploy; I am concerned that the lander will just float away or tumble if it is not tethered to the comet. I do not know the mass or the diameter of the comet, but the 100-kg lander is probably light as a feather in the weak gravitational field of the comet (note to Gotcha gang: not literally).

daoudmbo said: Awesome that it made the landing safely! Hope pictures do get released. But one thing I note in the BBC article about it (and have seen elsewhere): "One theory holds that comets were responsible for delivering water to the planets. Another idea is that they could have "seeded" the Earth with the chemistry needed to help kick-start life." I apologize, I am speaking from ignorance, but why should this be the case? Why would there be any greater likelihood that the chemistry or water would exist on a comet, but not on a planet like Earth (billions of years ago etc)?

daoudmbo said: Why would there be any greater likelihood that the chemistry or water would exist on a comet, but not on a planet like Earth (billions of years ago etc)?

Matt Young said: Unfortunately, according to CNN, the harpoons failed to deploy; I am concerned that the lander will just float away or tumble if it is not tethered to the comet.

bart.declercq said: Basically, it has to do with where the object formed - the closer to the sun during formation, the less "lighter elements" would have been present in the mix - hydrogen is a very light element, which is why there's lots more of it in the further reaches of the solar system (Jupiter is 90% hydrogen). Comets formed in the outer reaches of the solar system and are mostly made of ice (both water ice and frozen carbon dioxide), while the earth is mostly made up of metals, silicate rocks and carbon, with a mostly nitrogen atmosphere. Furthermore, the formation of earth was very violent, with planetesimals (proto-planetary bodies) slamming into each other, which vapourised a lot of material and turned the surface into boiling hot lava for quite some time, evaporating off much of the lighter stuff that was near the surface. Once the earth cooled down, a steady rain of water and carbon bearing comets would have added back a lot of the lighter elements.

It's landed and it's talking :)

gdavidson418 said:

TomS said: And what if they discover a trace of RNA?

Yes, but what if it finds The Designer? Glen Davidson

Matt Young said: Unfortunately, according to CNN, the harpoons failed to deploy; I am concerned that the lander will just float away or tumble if it is not tethered to the comet. I do not know the mass or the diameter of the comet, but the 100-kg lander is probably light as a feather in the weak gravitational field of the comet (note to Gotcha gang: not literally).

The Beeb remarks that some kind of reverse thruster also failed to fire, and the probe may have bounced when it hit. It now sits 4 cm into the surface, which may, I suppose, stabilize it. They will decide tomorrow whether to fire the harpoons. When is perihelion?

Perihelion for the comet looks like 13 August 2015.

http://en.wikipedia.org/wiki/67P/Churyumov%E2%80%93Gerasimenko

Pictures: https://www.flickr.com/photos/europeanspaceagency/sets/72157638315605535/ !

Oooh! Nice pix!

Look at the gas jets in the pic taken on 10 September. Reminded me that I gave a problem to my class: What does their "sat" weigh on the asteroid? There are at least 2 correct ways to solve the problem. Two of my 10 teams got the easy way:

In this case, the comet's diameter is 4 km; the earth's diameter is about 13,000 km. If the density of the comet is the same as that of earth, then the lander weighs a factor of (4/13,000)² less than on earth. I hate to use the kilogram as a unit of force, but it "weighs" about 10 mg (actually less, because the comet is surely less dense than the earth, but you get the idea).

Its mass is still 100 kg, and you have to accelerate a mass of 100 kg, but still it takes only a very small force to blow it off the surface and start it drifting. All the more remarkable to me that it returned to the surface after 1 bounce. Someone else can calculate the escape velocity.

Curses! I did that calculation wrong -- but I assure you that the freshmen got it right. I forgot to include the relative masses of the earth and the comet; no wonder I got a B in freshman physics. Anyway, when you do it right, you get 4/13,000, not the square, so about (1/3000)x100 kg, or 30 g. Much heavier, but still not a great weight, and quite a bit less if the comet is less dense than the earth. Or so I think.

Makes ya proud to be human, eh? For all the ways in which we're a mess, we are capable of amazing things. If only we had the will to be amazing more often....

Pierce R. Butler said: Pictures: https://www.flickr.com/photos/europeanspaceagency/sets/72157638315605535/ !

XKCD, probably the second best* comic strip on Earth, listens in for the landing.

_{(*The first best is, of course, Wiley's 'Non-Sequitur', but they're not talkin)}

Any idea what the albedo of the thing is? There's no referent to tell how "dark" the surface actually is. All you have are relative sunlit and shadowed areas.

Are you sure that's a gat jet on Sept 10? Could it be an over exposed camera flare of some sort? (That was my first guess on some of the overexposed closeups. Or do you think they were deliberately over exposing the shot in order to capture the otherwise very faint jet?

The albedo is 99%, according to this article:
http://www.bbc.com/news/science-environment-29525157

The albedo is 99%, ....

Matt Young said: All the more remarkable to me that it returned to the surface after 1 bounce. Someone else can calculate the escape velocity.

Ars Technica has a succinct summary of the status as we know it.

ksplawn said: Ars Technica has a succinct summary of the status as we know it.

Here is the Ars Technica site. Looks like it bounced twice and came to rest in the shadow of a ridge, which limits its exposure to sunlight. The harpoons were supposed to prevent bouncing but failed to deploy.

I am loath to diminish anything about this amazing accomplishment, but... It seems that some tests done (I think well after launch) showed that the nitrocellulose (gun cotton) charge used for the harpoons is almost assured not to work in a vacuum. I can dig out the reference to the article if requested. I am surprised they didn't foresee possible issues like not landing flat on all three pads and incorporate a lot of redundancy in their tethering requirements. I hope they can still perform at least some of the tests they hoped to do. Pictures are nice but data about composition would be great.

As you said, most of the available test results on guncotton in a vacuum seem to have been done well after the launch of the probe. As for redundancy, there is a severely constraining mass budget to consider. The researchers and designers wanted as many scientific instruments as possible, and if there was a problem with the grappling system then a second chance would be iffy anyway, so they likely weighed the risks and benefits of making a reusable (or redundant) grappling system and decided that the scientific objectives would be more important.

To help keep things in perspective, maybe it's worth remembering that we live at a time when it's possible to botch a cometary landing by a robotic probe. :)

(And yes, sorry about the copy/paste fail. Seems the ESA isn't the only one having trouble with their anchors!)

Also, I've read that it may be possible to use the lander's legs for a kind of "hopping" maneuver to free the probe and, potentially, land it somewhere else in a better position. If the ESA chooses to do this, it'll likely be as a last ditch attempt to move the probe when its batteries start running low and after they've gathered all the data they feel they can gather in the current orientation. Basically, once they've got nothing left to lose.

It's worth mentioning that this same technique has been suggested in several comment threads, based on people's experience with the rocketry sim game Kerbal Space Program. Actually, that game has been heavily referenced in just about every discussion of the landing I've seen in recent weeks. Just goes to show how much science and space literacy can be had by disguising the topic as a game!

Matt Young said:

The albedo is 99%, ....

No, that's Enceladus -- the comet's albedo is 4-6 %, according to the same article.

ngcart2011 said: I am loath to diminish anything about this amazing accomplishment, but... It seems that some tests done (I think well after launch) showed that the nitrocellulose (gun cotton) charge used for the harpoons is almost assured not to work in a vacuum. I can dig out the reference to the article if requested. I am surprised they didn't foresee possible issues like not landing flat on all three pads and incorporate a lot of redundancy in their tethering requirements. I hope they can still perform at least some of the tests they hoped to do. Pictures are nice but data about composition would be great.

Also, I’ve read that it may be possible to use the lander’s legs for a kind of “hopping” maneuver to free the probe and, potentially, land it somewhere else in a better position. If the ESA chooses to do this, it’ll likely be as a last ditch attempt to move the probe when its batteries start running low and after they’ve gathered all the data they feel they can gather in the current orientation. Basically, once they’ve got nothing left to lose.

Contrary to The Guardian, Science says that they are using the drill and the hammer for their intended purposes, despite the risks, and may use the legs for (randomly, I assume) hopping to another site.

It's sleeping. But it is out around the orbit of Mars, where the sunlight is perhaps half that at Earth's orbit, so it still may wake up.

So, let me be sure I understand the current situation correctly.

1. We have a $1.8 billion dollar piece of equipment that requires solar radiation for power.

2. The $1.8 billion dollar piece of equipment had a critical operation (anchoring harpoons deployment) fail.

3. The $1.8 billion dollar piece of equipment bounced from the designated landing site and has come to “rest” in the shadow of a cliff face blocking almost all of the Sun's light.

4. The $1.8 billion dollar piece of equipment, and all on-board instruments and experiment packages, are in an idle mode (everything is shutdown, in other words).

5. BUT, it's possible that things could change at some point (perhaps months from now) and it could be awaken to continue its mission. Or not.

Not bad so far for a $1.8 billion dollar mission? Hmmm …I could scream!

Keelyn said: So, let me be sure I understand the current situation correctly..... (snip) Not bad so far for a $1.8 billion dollar mission? Hmmm …I could scream!

stevaroni said:

Keelyn said: So, let me be sure I understand the current situation correctly..... (snip) Not bad so far for a $1.8 billion dollar mission? Hmmm …I could scream!

Well, don't forget that there's more to the mission than the lander. True, the lander is icing on the cake, but the cake is pretty impressive in it's own right. The orbiter, Rosetta, is still up there, as it has been for months, and it's been using its full suite of scientific instruments every day, as it will long into the future, as the comet approaches the sun and things start to get really interesting. It is, by cometary probe standards, an amazingly long-term observer, ready to watch a really interesting point in the comets lifetime. The lander, of course, carries other instruments that work best in actual contact and ts loss is, well a loss, but it did spend about 60 hours on the comets surface taking measurements before the batteries died. True, there were some instruments that didn't work, like the sample drill, but there were others that quietly and stoically ran for their full planned time. Unfortunately, the organizations involved in launching the instruments are keeping their cards close to their chest until their own investigators have a couple of months to publish the initial discoveries, and this is giving everyone the impression that not much came back from little Philae. Even given the accomplishments of previous probes like Giotto, Stardust and Deep Impact, I'd venture a bet that when all is said and done this one mission probably doubled the hard data about comets over what mankind had gathered in the last 3000 years.

Keelyn said: Not bad so far for a $1.8 billion dollar mission? Hmmm …I could scream!

Keeping this in perspective, compare just one single example - out of many - of the risks and costs of what politicians want to do with taxpayer money with that of what scientists would like to do with taxpayer money.

Think of people like Paul "Lies-From-the-Pit-of-Hell" Broun being the chairman of a "science' committee in Congress.

And speaking of other people's money, how about that slick Wall Street crowd?

Our Republican politicians haven’t appeared to be in touch with any kind of reality for at least the last 15 years; and they have repeatedly tried to shuck the blame for their messes all onto Obama. How's that for intelligence and foresight?

I think I'll stick with the science.

Consider what a small country spent on its Singapore Sports Hub: $1.3 billion.

I presume that Keelyn knows that Rosetta was funded by the European Space Agency.

(I think NASA pulled out of the project early on and the US contribution to funding was either low or zero. But, I didn't look hard enough to find a cost breakdown.) Continuing...

I presume that Keelyn is a US citizen, so very concerned about precious tax money being wasted on frivolous projects, and not a Citizen of the World concerned for the same reason.

Finally, I presume that Keelyn would agree that feeding every American a single $5 breakfast, one day, at about the same cost of $1.8, for which they would say "yum yum" once and crap out 8 hours later, thus, leaving humanity at no net gain in knowledge, but less hungry for an hour or two would be a better use for that money.

Congratulations, Keelyn, you have graduated to the rank of Junior Troll, Second Class.

Feeding hungry people is too socialist an idea. The Republicans would prefer to give the money to people like the Koch brothers, so that they can spend it wisely (ie, buying the next election).

Ha.

richard09 said: Feeding hungry people is too socialist an idea. The Republicans would prefer to give the money to people like the Koch brothers, so that they can spend it wisely (ie, buying the next election).

KlausH said: Republicans are against the GOVERNMENT taking other peoples' money to give it, without consent, to charity programs that GOVERNMENT favors.

Doc Bill said: Congratulations, Keelyn, you have graduated to the rank of Junior Troll, Second Class.

Oh dear. I think we will declare further discussion of the role of government in anything but science to be out of bounds, preferably before we descend into a hissing match.

Keelyn's comment is not necessarily trollish, I think, but it seems to be based on a misunderstanding -- in fact, the primary battery ran for several days, and the lander apparently sent back gobs of data and did almost everything it was supposed to do. That the solar panels cannot get enough sunlight is unfortunate, but not an indication that the money was wasted; far from it. See the trove of pictures that Mr. Butler linked to, for example, and wait for the scientific analyses.

I presume that Doc Bill meant "$1.8 billion". I thought that the money was well spent, though I would agree with him if I thought that not spending that money would necessarily feed anyone; it would not.

KlausH said: Republicans are against the GOVERNMENT taking other peoples' money to give it, without consent, to charity programs that GOVERNMENT favors.

You mean, like the National School Lunch Program National Science Foundation?

Doc Bill said: I presume that Keelyn knows that Rosetta was funded by the European Space Agency. (I think NASA pulled out of the project early on and the US contribution to funding was either low or zero. But, I didn't look hard enough to find a cost breakdown.)

I presume that Keelyn is a US citizen, so very concerned about precious tax money being wasted on frivolous projects, and not a Citizen of the World concerned for the same reason.

Keelyn said: Cassini had its problems, too, but it was still a stunning success. I would say that just accomplishing what the project has so far (like getting there on the bullseye, for example – not mention possible future discoveries) is worth every cent.

Finally, I presume that Keelyn would agree that feeding every American a single $5 breakfast, one day, at about the same cost of $1.8, for which they would say "yum yum" once and crap out 8 hours later, thus, leaving humanity at no net gain in knowledge, but less hungry for an hour or two would be a better use for that money.

Congratulations, Keelyn, you have graduated to the rank of Junior Troll, Second Class.

phhht said:

KlausH said: Republicans are against the GOVERNMENT taking other peoples' money to give it, without consent, to charity programs that GOVERNMENT favors.

You mean, like the National School Lunch Program National Science Foundation?

KlausH said:

phhht said:

KlausH said: Republicans are against the GOVERNMENT taking other peoples' money to give it, without consent, to charity programs that GOVERNMENT favors.

You mean, like the National School Lunch Program National Science Foundation?

Last I checked, the Republicans kept approving funding for NSF. I admit the Coburn Amendment was a stupid and ill-conceived reaction to far left "studies".

Oh dear, again. Rational and not excessively sarcastic responses please, people!

Yeah, what's a "far left study"? Investigating something the Fox/Limbaugh crowd find uncomfortable, like, oh, shrinking of Alaskan glaciers? How about anything involving evolution, which certain right-wingers think is straight from the pit of Hell? What could be more "far left" than that?

Matt Young said: Oh dear, again. Rational and not excessively sarcastic responses please, people!

To clarify, I did not mean any sarcasm whatsoever in my last post. All my questions are serious and, if I may say so, rational.

Matt Young said:

To clarify, I did not mean any sarcasm whatsoever in my last post. All my questions are serious and, if I may say so, rational.

I should have said "serious," rather than "rational." That said, I thought your comment about "the socialistic practices of the NSF," etc. was, if not sarcastic, then dangerously close. If you did not mean it that way, then I apologize for misconstruing it.

No, you see, 'socialist' is a dirty word, so if there's something a Republican likes, it can't, by definition, be socialist. And if Barack HUSSEIN Obama backs anything, even laissez faire capitalism, then that is socialist. Until 2 years from now, when he's out of office. Then it won't be socialist anymore, and they can vote for it, just like they did 7 years ago.

KlausH said: Last I checked, the Republicans kept approving funding for NSF. I admit the Coburn Amendment was a stupid and ill-conceived reaction to far left "studies".

I'm wondering where all the IDers are on this. What does ID tell us about what we should find on comets? Does it say anything at all?

scienceavenger said: I'm wondering where all the IDers are on this. What does ID tell us about what we should find on comets? Does it say anything at all?

I had no idea my comments would illicit that sort of assessment of me.

TomS said:

scienceavenger said: I'm wondering where all the IDers are on this. What does ID tell us about what we should find on comets? Does it say anything at all?

What is the ID position on geocentrism? Do they say that it is not a matter of "design", "information", or "naturalism", so they will include geocentrists under the Big Tent?

scienceavenger said: I'm wondering where all the IDers are on this. What does ID tell us about what we should find on comets? Does it say anything at all?

eric said:

scienceavenger said: I'm wondering where all the IDers are on this. What does ID tell us about what we should find on comets? Does it say anything at all?

There was only a 1E-900 chance that the lander would bounce exactly the way it did and end up in exactly the position it did...therefore, this was God bouncing it like a basketball, not undirectected (pfaugh!) physics.

Stupid Microshaft tablet! I wrote "some", not "omen". The surface RT keeps changing words all on its own, without notification. MS always thinks it knows better than the user.

Eric said: There was only a 1E-900 chance that the lander would bounce exactly the way it did and end up in exactly the position it did...therefore, this was God bouncing it like a basketball, not undirectected (pfaugh!) physics.