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As late as 12 November, the ESA's own FAQ [1] was stating that Philae's minimum mission target was one week of surface operation (powered entirely by primary ba

by justsee 12y ago

As late as 12 November, the ESA's own FAQ [1] was stating that Philae's minimum mission target was one week of surface operation (powered entirely by primary batteries), with even more operational time powered by back-up batteries (themselves recharged by solar) - resulting in an expected surface operation period measured in months. They airbrushed the FAQ on 12 November to remove mention of the minimum one week mission target, and inserted among other things '2.5 days'. [2] A diff of the two versions would probably be interesting. Now with the lander mission prematurely ended an associated scientist is tweeting a very rosy summary [3]: "What a perfect ending. All the science completed, data received. Primary mission successful. Well done everybody." How can a week of carefully-planned scientific activities be 'completed' in only 2.5 days? It seems implausible. How did the primary and secondary batteries not power the lander for the calculated one week+ of operation? Why aren't they open about what clearly seems to be a major failure with the scientific mission? It seems a case of intense bureaucratic / political pressure to change targets after they aren't met, and the fact scientists are participating in this is pretty disappointing. [1] https://web.archive.org/web/20140805030451/http://www.esa.int/Our_Activities/Space_Science/Rosetta/Frequently_asked_questions https://web.archive.org/web/20140805030451/http://www.esa.in... [2] http://www.esa.int/Our_Activities/Space_Science/Rosetta/Frequently_asked_questions http://www.esa.int/Our_Activities/Space_Science/Rosetta/Freq... [3] https://twitter.com/rocketeddy/status/533421309553016832 https://twitter.com/rocketeddy/status/533421309553016832

acqq 12y ago
The targets have to change during the mission. The initial plan was even the another comet. It shouldn't matter. http://en.wikipedia.org/wiki/Rosetta_%28spacecraft%29 http://en.wikipedia.org/wiki/Rosetta_%28spacecraft%29 "Rosetta was set to be launched on 12 January 2003 to rendezvous with the comet 46P/Wirtanen in 2011. This plan was abandoned after a failure of the Ariane 5 carrier rocket during a communications satellite launch on 11 December 2002, grounding it until the cause of the failure could be determined." No reason to blindly stick to the initial target when you're doing something for the first time ever. It's not that you planned to drive from your home to the shopping mall and have to excuse to your other that you went drinking beer instead. You would probably complain that it's not an initial comet now too? The device landed on the darn comet! After travelling 6 billion km in 10 years. Managed to work a few days and send the data! First time ever! Powered only by the solar energy! (+) In the outside temperature of absolute zero. How many firsts do you need? https://www.youtube.com/watch?v=uEY58fiSK8E https://www.youtube.com/watch?v=uEY58fiSK8E Nothing built by humans was ever on the comet surface before. This thing even worked. +) Edit: Thanks to jdiez17 for pointing that the lander used a non-rechargeable battery on the comet surface. It was all the time planed to do the main work with that battery. The solar powered work wasn't the primary objective.
- jdiez17 12y ago
  To be completely fair, it was not powered by solar energy - the experiments were run on power from the non-rechargeable battery. Which is fine, this is what Philae was designed to do. It looks like they completed all the objectives in the First Science Sequence (FSS), which was the lander's primary mission.
  - acqq 12y ago
    And also to be fair, the whole mission didn't depend on any RTG technology, used only by the US and Russia in space: https://news.ycombinator.com/item?id=8610585 https://news.ycombinator.com/item?id=8610585
    - jdiez17 12y ago
      While it would have been convenient to have a RTG onboard, it would have made the lander too heavy (with the current RTG technology. Smaller nuclear generators are possible in theory but none have been built yet.)
      - acqq 12y ago
        Yes, the lander was around 100 kg, whereas RTG would weight around 40 kg alone. And it would anyway be needed only in this case of unfortunate landing in the shadow. Once we talk about details it's clear how a lot of the complaints are based purely on a huge ignorance. It's good to ask to learn. But when somebody starts from the position that people who managed 25-year mission missed something to him "simple and obvious"...
        hrjet 12y ago
        > It's good to ask to learn. In that spirit, I have a question. How heavy are the solar panels? If their weight is comparable to 40kg then it makes RTG more attractive.
        12y ago
danmaz74 12y ago
Their mistake was to state a _minimum_ target mission like that in the first place, when you know that this is an incredibly complicated mission.
- acqq 12y ago
  Even that isn't the mistake at all. It's a good strategy to prepare to do a lot, then when some things go wrong, at least some of all things we're prepared for work. If you set the goals too low, you'll do much less. Therefore, the basic plan was to do the most of the work during a short time period. But they prepared to be able to do something interesting for much longer, if everything goes as perfect as it ideally could. The mistake would be allowing others to feed on smaller-effect non working stuff instead of the things that amazingly worked.
  - danmaz74 12y ago
    Yes but you don't need to announce that in a public FAQ ;)
    - dodyg 12y ago
      Damn straight. The top commenter treats the public FAQs of some kind of post-mortem report.
Osmium 12y ago
> It seems a case of intense bureaucratic / political pressure to change targets after they aren't met, and the fact scientists are participating in this is pretty disappointing. This is a big leap to make from the available evidence. Mission targets change all the time. It's a very fluid situation with many unknowns, so I don't find it at all surprising. I think calling foul play is premature to say the least.
- justsee 12y ago
  Do you think changing the mission target of a 12 year mission on the day of landing has a scientific or bureaucratic / political motive? I'm inclined to believe it is the latter. Until 12 November the FAQ [1] stated: During the first week – the minimum mission target – a first run of the most important scientific measurements will be completed. During this phase the lander can operate on primary battery power, should this be necessary. In a second phase that is meant to last up to three months, a secondary set of observations will be conducted, using backup batteries that will be recharged by the energy from the solar cells on the lander. However, no one knows precisely how long the lander will survive on the comet. Editing to omit the minimum mission target on 12 November [2] indicates something was already wrong at that stage, which would presumably relate to the two batteries that were to power the lander over more than a week, but no public announcement of any issue like that was made. So we should instead assume the batteries were fully operational. Instead we have ESA announcements and news articles asserting that the reason for the very short period of operation was a lack of solar power, but solar was never planned to be required for over a week at least. It seems obvious that they had a battery failure. That would not be surprising, but why not openly announce it? [1] https://web.archive.org/web/20140805030451/http://www.esa.int/Our_Activities/Space_Science/Rosetta/Frequently_asked_questions https://web.archive.org/web/20140805030451/http://www.esa.in... [2] https://web.archive.org/web/20141112043243/http://www.esa.int/Our_Activities/Space_Science/Rosetta/Frequently_asked_questions https://web.archive.org/web/20141112043243/http://www.esa.in...
  - sherjilozair 12y ago
    Because it's not important. What is more important is that the First Science Sequence was finished. In a detailed report, you may find that the battery didn't last as much as they thought it did (perhaps because of the double landings Philae had to make, etc.), but a public-facing article is not the place for it. Also, there are probably N things that didn't happen as they thought it did. It is better to mention the K important things (K << N), than the N unimportant things that they got wrong. If Philae, for example, didn't land on the comet at all, then they would have announced something like this: "Philae took a drive-by of the comet 67 p, and has done in-air experiments that would be valuable for us".
adventured 12y ago
The time variance is not very interesting to me at all, but the question of how or if they were able to get at least a week's worth of science done in 2.5 days, is very interesting to me. Was all the science completed, or just a fraction of it? Did they originally plan for only doing a day or two of science (with anything else being a plus), so the short mission life wasn't a problem?
- acqq 12y ago
  How about first learning which experiments were actually supposed to be done? Can you list them? Can you explain what they are about? Then we can try to consider how much of which of those were done and what are the actual consequences of different schedules in their execution. We can expect the years of scientific papers based on the analysis of the raw data made by this mission.
avar 12y ago
Here's a word diff between the two FAQ versions you posted: https://gist.github.com/avar/29d060e178e8fac4e2a3#file-faq-word-diff-txt https://gist.github.com/avar/29d060e178e8fac4e2a3#file-faq-w... Just search for "[-" to find deleted entries and "{+" to find added entries.
Arnt 12y ago
They got there, landed and carried out the primary science mission. They didn't even start on the secondary work (AFAICT), but that's called secondary for a reason. At a guess, the primary science mission was done so quickly because that's what they did. They might have spent more watts on locating the lander, for instance, or on taking pretty pictures.
petercooper 12y ago
It seems a case of intense bureaucratic / political pressure to change targets after they aren't met This is essentially the European Union's modus operandi.
gtirloni 12y ago
It's disappointing that this is the most upvoted comment in this thread. The mission was a success and will enable the scientists to understand much more about the whole thing. Plus, the orbiter will continue to track the comet and there is a chance the lander will come back from hibernation mode once there is more sunlight available. I think people in general have come to expect the incredible lifetime of the Mars landers as the norm. It's not. But since this is HN, I'm sure we all in the IT world are pretty confident in our estimations and our projects are a complete success all the time. Might explain why we are so disappointed with ESA. </sarcasm>
- turbohz 12y ago
  Many might not agree with the conspiracy tone of the comment, but we can see that there's something to be explained.
- cjensen 12y ago
  The mission was not a success: it did not meet their minimum goal of one week. Failure happens and is nothing to be ashamed of when trying for such an ambitious goal. ESA needs to own it and move on.
  - LastZactionHero 12y ago
    Tough crowd.
  - arrrg 12y ago
    It’s not a failure, though. Clearly not. Obviously not. To call this a failure is flat out insane. It has no connection to any reality. Also, it’s not a dichotomous failure/success condition. Some things worked, some things didn’t. That’s the actual situation. That much is obvious. It seems they actually managed to fulfill all the primary goals, though you will probably have to wait for the published papers to assess the quality of the collected data. Could take a couple years.
shiven 12y ago
Either I am failing to grasp what you are saying or you are completely naive about the humongous risk involved in cutting edge science of any kind. This ain't some piddly kickstarter trinket. And exactly what was promised that you didn't get your money's worth for? Speaking as a researcher in the biological sciences, funded by public tax-payer sources only (don't forget, I also pay taxes), the risk of failure is absolutely astronomical with every project I have ever undertaken. The fact that those projects have succeeded the way they did, is, at least in my mind, phenomenal. Even then, none of these projects, or any projects of any other scientist in my field, have ever achieved all their stated goals. If this rankles you, move to a place without public funding of science and bet your money on trinkets put up on kickstarter. Or if they are not trinkets, but are true attempts at solving hard problems(curing HIV/cancer, landing on a comet), I hereby guarantee that none of them will succeed 100% of their stated targets.
- johnchristopher 12y ago
  > This ain't some piddly kickstarter trinket. And exactly what was promised that you didn't get your money's worth for? Parent never stated he wanted his money's worth. He points out some obvious history rewriting which highly harm Science's image (IMNSHO). In no way does that diminishes this mission's outcome, results, feats and the admiration it rightly deserves. I don't understand the hostility here for a valid question about something that has nothing to do (obligatory political rewriting, maybe ?) with what was achieved. > I hereby guarantee that none of them will succeed 100% of their stated targets. But you don't lower your expectations after the facts and state "look, we did it as we told we were going to do it".
  - nolok 12y ago
    This is because parent and you are confusing a FAQ meant as a "what is the project going to do in its current state" for the general public with the blueprint and historic objectives and logs of the mission. The mission's goals changed a hundred time since the project conception in the eighties, each of those version is archived, but it makes sense that the "space tourism" text meant to explain to everyday Joe what the mission is doing / has done reflects the up to date status.
Ilverin 12y ago
Not directly relevant, but why not spend the minute necessary to google whether the explanation for "How did the primary and secondary batteries not power the lander for the calculated one week+ of operation?" is readily available? (it is: The harpoons failed to deploy leading the lander to bounce off of its landing target and land in a crater where the solar panels intended to increase its battery life had limited sunlight. http://www.vox.com/2014/11/13/7214941/philae-comet-rosetta http://www.vox.com/2014/11/13/7214941/philae-comet-rosetta )
- justsee 12y ago
  1. The primary non-rechargeable battery was designed to power it for a whole week. 2. The secondary rechargeable battery was designed to continue powering it for months after that. The detail you include is only relevant to 2, and keep in mind it is reasonable to assume that the secondary battery was fully charged before descent.
  - acqq 12y ago
    > it is reasonable to assume that the secondary battery was fully charged before descent Actually, no, it's not, unless you show something to prove that. Have you ever designed the device with two different power sources supposed to work on a comet after travelling 10 years through the space and being launched from the orbiter? I haven't, and can't claim it's reasonable to assume, whereas being an engineer I can imagine a lot of reasons for the directly opposite claim. What are your experiences or citations that allow you to claim that? Please state them or avoid uninformed claims. Specifically, if the secondary batteries were supposed to be fully charged before, why would the non-rechargeable batteries be the primary batteries at all? And technically, there are more primary batteries and more secondary batteries in Philae, the primary batteries having 1000 Wh, the secondary batteries having 140 Wh. Note that if you use e.g. 30 W during experiments, you use the primary batteries in some 30 hours. The scientists had to decide the rate of the battery use. Just like your mobile phone lasts only hours if you speak all the time on it. The lander being in the shade had different temperature environment than in the ideal case. It's extremely cold there and the high enough temperature is necessary for the things to work. Compare all that with your modem constantly using 10 W, your computer, if notebook, using probably 20 W for serious work. Even without the heating problem, you wouldn't be able to use internet and work for more than 30 hours with Philae's primary batteries, and certainly not for 4 days.
Voloskaya 12y ago
The primary objective was always planned to last few days, and it did that part pretty much perfectly (80-90% of results were received). After these few days, there was a secondary objective, which was to turn Philae into a kind of weather station on a comet, with pretty much every instrument turned off. It would have been great if it had worked of course, but compared to the main objective it doesn't really matter. What they really want to know is the chirality of the water on the comet and wether or not the comet contains certain elements, it seems like they manage to get this data. Also the secondary objective is not totally abandonned, since there is still a chance to see Philae back in some months, with the comet getting much more sunlight and warming considerably. Plans change with time, and the FAQ is adapted to those plan. Hell iirc there wasn't even suppose to be a lander in there initial plan 25 years ago.
melling 12y ago
"Why aren't they open about what clearly seems to be a major failure with the scientific mission?" Human nature. Haven't you worked in a corporate environment where people try to spin to the positive? A lot of money was spent and people want to feel good about the results. When they sold the project, the PowerPoint needed to present a great show or it wasn't going to get funded. A 1 week minimum was probably needed. Anyway, I could go on but just try observe human nature, otherwise people will accuse you of being negative. As for me, I thought it turned out to be a great because it became a mainstream story. We should be putting 4k video cameras on new craft. Get people excited so we can get a budget to build 10 times as many vehicles.
- Semiapies 12y ago
  Bandwidth's surprisingly limited on these missions, so 4K cameras, while awesome, would be problematic.
skywhopper 12y ago
I'm assuming they burned through much of the initial battery charge trying to establish contact, determine orientation, right the lander, etc. So it may have been able to operate for a week had they not had to do a lot of things they hadn't planned on. Yes, they want to give things a positive spin, but they aren't being disingenuous. They have learned a lot from this, and they got to run tests with all of the equipment on the lander. Calling it a major failure is way off base. You often learn more from things going wrong than from when they go right. Maybe not the things you were planning on learning, but this is very far from a failure. I also think you're over-interpreting their "minimum mission target". That was an "if everything goes to plan" target. Everything didn't go as planned, but here's the thing: that's also in the plan. It is not possible to do this kind of mission without things going wrong. Usually when things go wrong, you get no data back. But despite the landing going terribly awry, we still got a lot of data back! If you consider this a failure or a disappointment, then I'm glad you don't work for the ESA. You are far too cynical to be able to get this kind of science done.
mikeash 12y ago
Why is this comment at the top? Why do I have to scroll down so far to get to any sort of interesting discussion about the lander? Pathetic.
johnchristopher 12y ago
So I went ahead and actually used kdiff. Here are the relevant passage. Honestly it looks more like live rewriting of the FAQ to take into account the fact that Philae had a bumpy landing. I don't see an intention to deceive. It's awkward to present the document without mentioning it's not the detailed mission objectives. That maybe the `perfect ending` considering we have some data back and well.. it's the only ending we have so rosetta exploding before philae could even be launched might have been labeled `perfect` too because it's the first time we put something into the orbit of a duck-like comet. They certainly wished they had more philae time though. That would have been even more perfect. I wouldn't qualify this a `major failure` though (does the hostility come from that ?). > The science observations will start immediately. During the first week – the minimum mission target – a first run of the most important scientific measurements will be completed. During this phase the lander can operate on primary battery power, should this be necessary. In a second phase that is meant to last up to three months, a secondary set of observations will be conducted, using backup batteries that will be recharged by the energy from the solar cells on the lander. However, no one knows precisely how long the lander will survive on the comet. And then: > The science observations will start immediately. During the first 2.5 days the first series of scientific measurements will be completed. During this phase the lander will operate on primary battery power. In a second phase that may last up to three months, a secondary set of observations will be conducted, using backup batteries that will be recharged by the energy from the solar cells on the lander. However, no one knows precisely how long the lander will survive on the comet.
skywhopper 12y ago
Having read the two different versions of the FAQ, I also have to dispute your thesis here. On November 12, that FAQ page was probably getting more hits in an hour than it had in its entire history up until then. Say you're in charge of communications, and due to the landing problems, the mission profile has just changed from best-case to medium-case. What's the point of a FAQ that's wrong? The question is "How long will the lander operate on the comet's nucleus?", not "How long did you originally promise the bureaucrats the lander would operate?" As the answers change, the FAQ page changes. The previous version of that page on the Internet archive doesn't mention the landing at all. So this isn't even a long standing promise. Probably they were making estimates and new guesses every few days as they got closer to the comet and learned more about it. The target mission duration probably depended on the location they landed, which wasn't decided until a few weeks ago. Anyway, the FAQ page is not the official mission planning document, and it's not meant to be a history of every change in the plan. It's a place to answer questions that the public and the press have about the current state of the mission.
TrevorJ 12y ago
I read somewhere that the odds they places on getting the thing to stick the landing at all was between 50 and 75%. We put a lander on a comet, I'd be celebrating the upside too if I was them.
Stratoscope 12y ago
While you work on those discrepancies, I'm going to enjoy this version of the story and let myself get a little teary-eyed over this astounding success: > @ESA_Rosetta I'm feeling a bit tired, did you get all my data? I might take a nap… #CometLanding > Thank you, @ESA_Rosetta! I did it! I became the first spacecraft to land on a comet & study it! But it’s not over yet… #CometLanding > My #lifeonacomet has just begun @ESA_Rosetta. I'll tell you more about my new home, comet #67P soon… zzzzz #CometLanding https://twitter.com/Philae2014 https://twitter.com/Philae2014
MichaelMoser123 12y ago
will it get more energy once it gets closer towards the sun? will it still be operational once it gets there?
arrrg 12y ago
It’s an FAQ. It tells you precisely nothing about anything. Don’t be stupid, don’t be conspiracy mongering please. Why is this trash up there? It’s insane that this crap is seen as a valuable contribution.
- TillE 12y ago
  This is the second thread in as many days that's been completely derailed by embarrassing, irrelevant crap. Embarrassing because somehow the comments still have scores over 0.
verytrivial 12y ago
I couldn't help but wish there was someone of NASA's calibre with respect to public outreach "handling" this. I really think they got the tone wrong -- 99% of the THOUSANDS of people watching this really just wanted to experience the adventure, warts and all. We know it's hard, we empathise. We wanted to experience the trill, terror and wonder. There really wasn't any need to clam up like they did. If only they had someone (higher profile? I really have been looking for a good feed from with ESA) who could walk around and ask for the pulse of the investigation. "We have no idea, and this is why ..." would still be fascinating. Edit: And I LOVE that NASA just has a raw feed of the images as they come down. I'm thinking of the Mars rovers here. I can't fault how those programmes are communicated.
snowwrestler 12y ago
The FAQ on a website is a current document. Once it became clear that only 2.5 days of work was possible, that is the new reality and it is not wrong to update the FAQ to reflect that. The original mission parameters were well documented--that has not changed because an FAQ was edited. There will undoubtedly be a detailed technical review that investigate every change from plan to execution. Again, a website FAQ is not the forum for that.

by justsee 12y ago

acqq 12y ago

The targets have to change during the mission. The initial plan was even the another comet. It shouldn't matter. http://en.wikipedia.org/wiki/Rosetta_%28spacecraft%29 http://en.wikipedia.org/wiki/Rosetta_%28spacecraft%29 "Rosetta was set to be launched on 12 January 2003 to rendezvous with the comet 46P/Wirtanen in 2011. This plan was abandoned after a failure of the Ariane 5 carrier rocket during a communications satellite launch on 11 December 2002, grounding it until the cause of the failure could be determined." No reason to blindly stick to the initial target when you're doing something for the first time ever. It's not that you planned to drive from your home to the shopping mall and have to excuse to your other that you went drinking beer instead. You would probably complain that it's not an initial comet now too? The device landed on the darn comet! After travelling 6 billion km in 10 years. Managed to work a few days and send the data! First time ever! Powered only by the solar energy! (+) In the outside temperature of absolute zero. How many firsts do you need? https://www.youtube.com/watch?v=uEY58fiSK8E https://www.youtube.com/watch?v=uEY58fiSK8E Nothing built by humans was ever on the comet surface before. This thing even worked. +) Edit: Thanks to jdiez17 for pointing that the lander used a non-rechargeable battery on the comet surface. It was all the time planed to do the main work with that battery. The solar powered work wasn't the primary objective.

jdiez17 12y ago
To be completely fair, it was not powered by solar energy - the experiments were run on power from the non-rechargeable battery. Which is fine, this is what Philae was designed to do. It looks like they completed all the objectives in the First Science Sequence (FSS), which was the lander's primary mission.
- acqq 12y ago
  And also to be fair, the whole mission didn't depend on any RTG technology, used only by the US and Russia in space: https://news.ycombinator.com/item?id=8610585 https://news.ycombinator.com/item?id=8610585
  - jdiez17 12y ago
    While it would have been convenient to have a RTG onboard, it would have made the lander too heavy (with the current RTG technology. Smaller nuclear generators are possible in theory but none have been built yet.)
    - acqq 12y ago
      Yes, the lander was around 100 kg, whereas RTG would weight around 40 kg alone. And it would anyway be needed only in this case of unfortunate landing in the shadow. Once we talk about details it's clear how a lot of the complaints are based purely on a huge ignorance. It's good to ask to learn. But when somebody starts from the position that people who managed 25-year mission missed something to him "simple and obvious"...
      - hrjet 12y ago
        > It's good to ask to learn. In that spirit, I have a question. How heavy are the solar panels? If their weight is comparable to 40kg then it makes RTG more attractive.
        12y ago

danmaz74 12y ago

Their mistake was to state a _minimum_ target mission like that in the first place, when you know that this is an incredibly complicated mission.

acqq 12y ago
Even that isn't the mistake at all. It's a good strategy to prepare to do a lot, then when some things go wrong, at least some of all things we're prepared for work. If you set the goals too low, you'll do much less. Therefore, the basic plan was to do the most of the work during a short time period. But they prepared to be able to do something interesting for much longer, if everything goes as perfect as it ideally could. The mistake would be allowing others to feed on smaller-effect non working stuff instead of the things that amazingly worked.
- danmaz74 12y ago
  Yes but you don't need to announce that in a public FAQ ;)
  - dodyg 12y ago
    Damn straight. The top commenter treats the public FAQs of some kind of post-mortem report.

Osmium 12y ago

> It seems a case of intense bureaucratic / political pressure to change targets after they aren't met, and the fact scientists are participating in this is pretty disappointing. This is a big leap to make from the available evidence. Mission targets change all the time. It's a very fluid situation with many unknowns, so I don't find it at all surprising. I think calling foul play is premature to say the least.

justsee 12y ago
Do you think changing the mission target of a 12 year mission on the day of landing has a scientific or bureaucratic / political motive? I'm inclined to believe it is the latter. Until 12 November the FAQ [1] stated: During the first week – the minimum mission target – a first run of the most important scientific measurements will be completed. During this phase the lander can operate on primary battery power, should this be necessary. In a second phase that is meant to last up to three months, a secondary set of observations will be conducted, using backup batteries that will be recharged by the energy from the solar cells on the lander. However, no one knows precisely how long the lander will survive on the comet. Editing to omit the minimum mission target on 12 November [2] indicates something was already wrong at that stage, which would presumably relate to the two batteries that were to power the lander over more than a week, but no public announcement of any issue like that was made. So we should instead assume the batteries were fully operational. Instead we have ESA announcements and news articles asserting that the reason for the very short period of operation was a lack of solar power, but solar was never planned to be required for over a week at least. It seems obvious that they had a battery failure. That would not be surprising, but why not openly announce it? [1] https://web.archive.org/web/20140805030451/http://www.esa.int/Our_Activities/Space_Science/Rosetta/Frequently_asked_questions https://web.archive.org/web/20140805030451/http://www.esa.in... [2] https://web.archive.org/web/20141112043243/http://www.esa.int/Our_Activities/Space_Science/Rosetta/Frequently_asked_questions https://web.archive.org/web/20141112043243/http://www.esa.in...
- sherjilozair 12y ago
  Because it's not important. What is more important is that the First Science Sequence was finished. In a detailed report, you may find that the battery didn't last as much as they thought it did (perhaps because of the double landings Philae had to make, etc.), but a public-facing article is not the place for it. Also, there are probably N things that didn't happen as they thought it did. It is better to mention the K important things (K << N), than the N unimportant things that they got wrong. If Philae, for example, didn't land on the comet at all, then they would have announced something like this: "Philae took a drive-by of the comet 67 p, and has done in-air experiments that would be valuable for us".

adventured 12y ago

The time variance is not very interesting to me at all, but the question of how or if they were able to get at least a week's worth of science done in 2.5 days, is very interesting to me. Was all the science completed, or just a fraction of it? Did they originally plan for only doing a day or two of science (with anything else being a plus), so the short mission life wasn't a problem?

acqq 12y ago
How about first learning which experiments were actually supposed to be done? Can you list them? Can you explain what they are about? Then we can try to consider how much of which of those were done and what are the actual consequences of different schedules in their execution. We can expect the years of scientific papers based on the analysis of the raw data made by this mission.

avar 12y ago

Here's a word diff between the two FAQ versions you posted: https://gist.github.com/avar/29d060e178e8fac4e2a3#file-faq-word-diff-txt https://gist.github.com/avar/29d060e178e8fac4e2a3#file-faq-w... Just search for "[-" to find deleted entries and "{+" to find added entries.

Arnt 12y ago

They got there, landed and carried out the primary science mission. They didn't even start on the secondary work (AFAICT), but that's called secondary for a reason. At a guess, the primary science mission was done so quickly because that's what they did. They might have spent more watts on locating the lander, for instance, or on taking pretty pictures.

petercooper 12y ago

It seems a case of intense bureaucratic / political pressure to change targets after they aren't met This is essentially the European Union's modus operandi.

gtirloni 12y ago

It's disappointing that this is the most upvoted comment in this thread. The mission was a success and will enable the scientists to understand much more about the whole thing. Plus, the orbiter will continue to track the comet and there is a chance the lander will come back from hibernation mode once there is more sunlight available. I think people in general have come to expect the incredible lifetime of the Mars landers as the norm. It's not. But since this is HN, I'm sure we all in the IT world are pretty confident in our estimations and our projects are a complete success all the time. Might explain why we are so disappointed with ESA. </sarcasm>

turbohz 12y ago
Many might not agree with the conspiracy tone of the comment, but we can see that there's something to be explained.
cjensen 12y ago
The mission was not a success: it did not meet their minimum goal of one week. Failure happens and is nothing to be ashamed of when trying for such an ambitious goal. ESA needs to own it and move on.
- LastZactionHero 12y ago
  Tough crowd.
- arrrg 12y ago
  It’s not a failure, though. Clearly not. Obviously not. To call this a failure is flat out insane. It has no connection to any reality. Also, it’s not a dichotomous failure/success condition. Some things worked, some things didn’t. That’s the actual situation. That much is obvious. It seems they actually managed to fulfill all the primary goals, though you will probably have to wait for the published papers to assess the quality of the collected data. Could take a couple years.

shiven 12y ago

Either I am failing to grasp what you are saying or you are completely naive about the humongous risk involved in cutting edge science of any kind. This ain't some piddly kickstarter trinket. And exactly what was promised that you didn't get your money's worth for? Speaking as a researcher in the biological sciences, funded by public tax-payer sources only (don't forget, I also pay taxes), the risk of failure is absolutely astronomical with every project I have ever undertaken. The fact that those projects have succeeded the way they did, is, at least in my mind, phenomenal. Even then, none of these projects, or any projects of any other scientist in my field, have ever achieved all their stated goals. If this rankles you, move to a place without public funding of science and bet your money on trinkets put up on kickstarter. Or if they are not trinkets, but are true attempts at solving hard problems(curing HIV/cancer, landing on a comet), I hereby guarantee that none of them will succeed 100% of their stated targets.

johnchristopher 12y ago
> This ain't some piddly kickstarter trinket. And exactly what was promised that you didn't get your money's worth for? Parent never stated he wanted his money's worth. He points out some obvious history rewriting which highly harm Science's image (IMNSHO). In no way does that diminishes this mission's outcome, results, feats and the admiration it rightly deserves. I don't understand the hostility here for a valid question about something that has nothing to do (obligatory political rewriting, maybe ?) with what was achieved. > I hereby guarantee that none of them will succeed 100% of their stated targets. But you don't lower your expectations after the facts and state "look, we did it as we told we were going to do it".
- nolok 12y ago
  This is because parent and you are confusing a FAQ meant as a "what is the project going to do in its current state" for the general public with the blueprint and historic objectives and logs of the mission. The mission's goals changed a hundred time since the project conception in the eighties, each of those version is archived, but it makes sense that the "space tourism" text meant to explain to everyday Joe what the mission is doing / has done reflects the up to date status.

Ilverin 12y ago

Not directly relevant, but why not spend the minute necessary to google whether the explanation for "How did the primary and secondary batteries not power the lander for the calculated one week+ of operation?" is readily available? (it is: The harpoons failed to deploy leading the lander to bounce off of its landing target and land in a crater where the solar panels intended to increase its battery life had limited sunlight. http://www.vox.com/2014/11/13/7214941/philae-comet-rosetta http://www.vox.com/2014/11/13/7214941/philae-comet-rosetta )

justsee 12y ago
1. The primary non-rechargeable battery was designed to power it for a whole week. 2. The secondary rechargeable battery was designed to continue powering it for months after that. The detail you include is only relevant to 2, and keep in mind it is reasonable to assume that the secondary battery was fully charged before descent.
- acqq 12y ago
  > it is reasonable to assume that the secondary battery was fully charged before descent Actually, no, it's not, unless you show something to prove that. Have you ever designed the device with two different power sources supposed to work on a comet after travelling 10 years through the space and being launched from the orbiter? I haven't, and can't claim it's reasonable to assume, whereas being an engineer I can imagine a lot of reasons for the directly opposite claim. What are your experiences or citations that allow you to claim that? Please state them or avoid uninformed claims. Specifically, if the secondary batteries were supposed to be fully charged before, why would the non-rechargeable batteries be the primary batteries at all? And technically, there are more primary batteries and more secondary batteries in Philae, the primary batteries having 1000 Wh, the secondary batteries having 140 Wh. Note that if you use e.g. 30 W during experiments, you use the primary batteries in some 30 hours. The scientists had to decide the rate of the battery use. Just like your mobile phone lasts only hours if you speak all the time on it. The lander being in the shade had different temperature environment than in the ideal case. It's extremely cold there and the high enough temperature is necessary for the things to work. Compare all that with your modem constantly using 10 W, your computer, if notebook, using probably 20 W for serious work. Even without the heating problem, you wouldn't be able to use internet and work for more than 30 hours with Philae's primary batteries, and certainly not for 4 days.

Voloskaya 12y ago

The primary objective was always planned to last few days, and it did that part pretty much perfectly (80-90% of results were received). After these few days, there was a secondary objective, which was to turn Philae into a kind of weather station on a comet, with pretty much every instrument turned off. It would have been great if it had worked of course, but compared to the main objective it doesn't really matter. What they really want to know is the chirality of the water on the comet and wether or not the comet contains certain elements, it seems like they manage to get this data. Also the secondary objective is not totally abandonned, since there is still a chance to see Philae back in some months, with the comet getting much more sunlight and warming considerably. Plans change with time, and the FAQ is adapted to those plan. Hell iirc there wasn't even suppose to be a lander in there initial plan 25 years ago.

melling 12y ago

"Why aren't they open about what clearly seems to be a major failure with the scientific mission?" Human nature. Haven't you worked in a corporate environment where people try to spin to the positive? A lot of money was spent and people want to feel good about the results. When they sold the project, the PowerPoint needed to present a great show or it wasn't going to get funded. A 1 week minimum was probably needed. Anyway, I could go on but just try observe human nature, otherwise people will accuse you of being negative. As for me, I thought it turned out to be a great because it became a mainstream story. We should be putting 4k video cameras on new craft. Get people excited so we can get a budget to build 10 times as many vehicles.

Semiapies 12y ago
Bandwidth's surprisingly limited on these missions, so 4K cameras, while awesome, would be problematic.

skywhopper 12y ago

I'm assuming they burned through much of the initial battery charge trying to establish contact, determine orientation, right the lander, etc. So it may have been able to operate for a week had they not had to do a lot of things they hadn't planned on. Yes, they want to give things a positive spin, but they aren't being disingenuous. They have learned a lot from this, and they got to run tests with all of the equipment on the lander. Calling it a major failure is way off base. You often learn more from things going wrong than from when they go right. Maybe not the things you were planning on learning, but this is very far from a failure. I also think you're over-interpreting their "minimum mission target". That was an "if everything goes to plan" target. Everything didn't go as planned, but here's the thing: that's also in the plan. It is not possible to do this kind of mission without things going wrong. Usually when things go wrong, you get no data back. But despite the landing going terribly awry, we still got a lot of data back! If you consider this a failure or a disappointment, then I'm glad you don't work for the ESA. You are far too cynical to be able to get this kind of science done.

mikeash 12y ago

Why is this comment at the top? Why do I have to scroll down so far to get to any sort of interesting discussion about the lander? Pathetic.

johnchristopher 12y ago

So I went ahead and actually used kdiff. Here are the relevant passage. Honestly it looks more like live rewriting of the FAQ to take into account the fact that Philae had a bumpy landing. I don't see an intention to deceive. It's awkward to present the document without mentioning it's not the detailed mission objectives. That maybe the `perfect ending` considering we have some data back and well.. it's the only ending we have so rosetta exploding before philae could even be launched might have been labeled `perfect` too because it's the first time we put something into the orbit of a duck-like comet. They certainly wished they had more philae time though. That would have been even more perfect. I wouldn't qualify this a `major failure` though (does the hostility come from that ?). > The science observations will start immediately. During the first week – the minimum mission target – a first run of the most important scientific measurements will be completed. During this phase the lander can operate on primary battery power, should this be necessary. In a second phase that is meant to last up to three months, a secondary set of observations will be conducted, using backup batteries that will be recharged by the energy from the solar cells on the lander. However, no one knows precisely how long the lander will survive on the comet. And then: > The science observations will start immediately. During the first 2.5 days the first series of scientific measurements will be completed. During this phase the lander will operate on primary battery power. In a second phase that may last up to three months, a secondary set of observations will be conducted, using backup batteries that will be recharged by the energy from the solar cells on the lander. However, no one knows precisely how long the lander will survive on the comet.

skywhopper 12y ago

Having read the two different versions of the FAQ, I also have to dispute your thesis here. On November 12, that FAQ page was probably getting more hits in an hour than it had in its entire history up until then. Say you're in charge of communications, and due to the landing problems, the mission profile has just changed from best-case to medium-case. What's the point of a FAQ that's wrong? The question is "How long will the lander operate on the comet's nucleus?", not "How long did you originally promise the bureaucrats the lander would operate?" As the answers change, the FAQ page changes. The previous version of that page on the Internet archive doesn't mention the landing at all. So this isn't even a long standing promise. Probably they were making estimates and new guesses every few days as they got closer to the comet and learned more about it. The target mission duration probably depended on the location they landed, which wasn't decided until a few weeks ago. Anyway, the FAQ page is not the official mission planning document, and it's not meant to be a history of every change in the plan. It's a place to answer questions that the public and the press have about the current state of the mission.

TrevorJ 12y ago

I read somewhere that the odds they places on getting the thing to stick the landing at all was between 50 and 75%. We put a lander on a comet, I'd be celebrating the upside too if I was them.

Stratoscope 12y ago

While you work on those discrepancies, I'm going to enjoy this version of the story and let myself get a little teary-eyed over this astounding success: > @ESA_Rosetta I'm feeling a bit tired, did you get all my data? I might take a nap… #CometLanding > Thank you, @ESA_Rosetta! I did it! I became the first spacecraft to land on a comet & study it! But it’s not over yet… #CometLanding > My #lifeonacomet has just begun @ESA_Rosetta. I'll tell you more about my new home, comet #67P soon… zzzzz #CometLanding https://twitter.com/Philae2014 https://twitter.com/Philae2014

MichaelMoser123 12y ago

will it get more energy once it gets closer towards the sun? will it still be operational once it gets there?

arrrg 12y ago

It’s an FAQ. It tells you precisely nothing about anything. Don’t be stupid, don’t be conspiracy mongering please. Why is this trash up there? It’s insane that this crap is seen as a valuable contribution.

TillE 12y ago
This is the second thread in as many days that's been completely derailed by embarrassing, irrelevant crap. Embarrassing because somehow the comments still have scores over 0.

verytrivial 12y ago

I couldn't help but wish there was someone of NASA's calibre with respect to public outreach "handling" this. I really think they got the tone wrong -- 99% of the THOUSANDS of people watching this really just wanted to experience the adventure, warts and all. We know it's hard, we empathise. We wanted to experience the trill, terror and wonder. There really wasn't any need to clam up like they did. If only they had someone (higher profile? I really have been looking for a good feed from with ESA) who could walk around and ask for the pulse of the investigation. "We have no idea, and this is why ..." would still be fascinating. Edit: And I LOVE that NASA just has a raw feed of the images as they come down. I'm thinking of the Mars rovers here. I can't fault how those programmes are communicated.

snowwrestler 12y ago

The FAQ on a website is a current document. Once it became clear that only 2.5 days of work was possible, that is the new reality and it is not wrong to update the FAQ to reflect that. The original mission parameters were well documented--that has not changed because an FAQ was edited. There will undoubtedly be a detailed technical review that investigate every change from plan to execution. Again, a website FAQ is not the forum for that.