Philae comet lander wakes up | Hacker News Reader

Philae comet lander wakes up

bbc.co.uk

922 pointsDangerousPie155 comments

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...

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!

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

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.

Here's a little bit more info on the nature of the signal received: http://blogs.esa.int/rosetta/2015/06/14/rosettas-lander-phil...

24W is pretty good. More data on the instrumentation onboard can be found in DLR's fact sheet [1]. So I'm guessing if the hardware has survived, we should see some more science data trickling in. Fingers crossed!

[1] http://www.dlr.de/dlr/Portaldata/1/Resources/documents/Phila...

Yes, the power is pretty good. The temperature is currently told as -35 degree Celsius. I wonder how fast would the temperature variations be, with respect to the movement of the comet and how the lander with adjust to that.

That temperature made me think that humans could survive there if only they were sheltered from the vacuum and radiation of space.

I expected the temperature to be much lower, could this temperature be on the sunny side?

I am also surprised. I guess its because the comet is near perihelion.

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.

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.

> 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 ;)

AFAIK it's similar to the processes for avionics software, but with even more attention to detail. This link came up recently on HN in reference to avionics:

https://en.wikipedia.org/wiki/DO-178B

http://cacm.acm.org/magazines/2014/2/171689-mars-code/abstra... is a good watch.

And you can get a fair bit of insight through many of the videos from Flight Software Workshop - http://flightsoftware.jhuapl.edu/files/_site/workshops/2014/

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

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

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

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/...

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

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.

The so-called "green parties" have caused a lot of environmental damage to Europe and the earth. Instead of relatively speaking quite safe nuclear power, in many places we are getting quite dangerous coal power. Pretty much just out of ignorance.

I think nuclear power is safest even in absolute terms not only relatively.

solar would seem to be safer, presuming you can manufacture the cells without causing environmental degradation.

Nope, at least not according to the figures I've seen (e.g., http://www.forbes.com/sites/jamesconca/2012/06/10/energys-de...). I think the main reason is that installing solar panels isn't perfectly safe. Nuclear comes out a long way ahead of solar -- but both are vastly ahead of coal.

Why? This cursory Google search https://www.google.co.in/search?q=death+per+terawatt seems to say nuclear has less kills per terawatt-hour than coal, though obviously quantifying deaths from all these power sources is hard.

The issue with this is how it calculates deaths per terrawatt.

Nuclear has the whole waste storage (and, in some places, drinking water contamination) issue, while coal has the whole climate change issue.

Both are bad, but just saying that one of them has less short-term, but more long-term deaths isn’t a good argument.

Imho, "the whole climate change issue" is a waste storage issue as well.

Except it doesn't kill people quite as quickly, so we're okay with it just being released into our atmosphere.

Have there been any documented cases of nuclear waste storage causing mortal danger, and if so, how do they compare to coal's waste storage (or, more precisely, the lack thereof)?

I don't know any details on either, but I'd suspect that the latter is a much greater threat than the former, and that the more we transition from coal to nuclear fission (and, alongside that, the more we develop ways to use nuclear waste more productively), the better.

The worst case is rather nasty though: the rendering of a large area uninhabitable and unusable for agriculture. There aren't a lot of sites in Europe where you can site a nuclear reactor far enough away to avoid either evacuating a major city or losing an agricultural region. There is no "away", as people like to say about rubbish.

Compare that large area to that consumed by business-as-usual for the alternatives though. E.g. the area rendered uninhabitable/unusable for hydro power is larger (per kwh). (Of course many people find a reservoir more attractive than a radioactive zone, but both are equally unusable for habitation or agriculture)

area rendered uninhabitable/unusable for hydro power is larger

That can be true of reservoirs (Lake Mead is huge) but isn't necessarily. UK's largest reservoir is https://en.wikipedia.org/wiki/Kielder_Water at a mere 2 miles by <6 miles, supporting a piddly 6MW (yes, megawatts not gigawatts, I had to double check that). But that's subject to planning permission in a way that radioactive exclusion zones aren't. The UK suffered from Chernobyl fallout for years: http://www.telegraph.co.uk/news/uknews/1514492/20-years-on-B...

It's not that nuclear power is bad on average, it's just that the worst case scenarios affect potentially huge areas.

A clarification to the point about Kielder's power generation: Kielder reservoir is primarily for regulating the water supply, rather than power generation. There are many hydro-electric plants in the UK generating much more power.

Germany's wind turbines and solar farms disagree. 30% of its energy is renewable.

(This is not technically a reply to you, but just some context in case anyone else is interested.)

For my own benefit, I have attempted to interpret the statistics in this relatively authoritative source: http://www.erneuerbare-energien.de/EE/Navigation/DE/Service/...

As far as I can tell, for the year of 2014, Germany's primary energy consumption breaks down approximately 15/35/20/30 for electricity generation, heating, transportation, and other [p.10]. Approximately 30% of the electricity generation is from renewable sources [p.5], which is split approximately 35/25/20/20 between wind, biofuels, solar, and other (including hydro) [p.6]. Nearly all of the contribution of renewable sources to heating and transportation is from biofuels [p.8--9].

tl;dr: Renewable energy accounts for approximately 30% of electricity generation in Germany. Overall, renewable energy accounts for approximately 11% of primary energy consumption.

That's a misleading number. Those devices embody a huge amount energy, which China supplied in the form of coal.

It'll be decades before they pay it back, in the meantime they just caused more CO2 in the air.

Nuclear would have been better.

Not that again. No it does not take decades to pay back the energy cost of the production of Wind Turbines or Solar Panels. Win turbines have an average payback time of 2-8 Months. Solar panels are far worse but even there the payback time for the complete System (Panel, Inverter, Installation, Transport) is between 2.5 Years to 1 Year depending on the panel technology [1]. These numbers are from a Frauenhofer Study from 2009 so one can assume that today's payback times are better than that due to slightly increased efficiency.

[1] http://c1cleantechnicacom.wpengine.netdna-cdn.com/files/2013...

100% agree, and all these "pay back" arguments forget the payback time of coal or nuclear systems.

I highly doubt it's that short, that would mean that after 1 year you would make back all your money and everything after is profit?

I've never seen any numbers even close to that, they all give decades to make make back your money, even when selling the electricity at retail, and certainly not when selling at wholesale.

In Germany old coal plants that were due to be decommissioned are now still running because nuclear plants are being switched off instead. Are you sure the good done by the greens outweighs the bad?

> In Germany old coal plants that were due to be decommissioned are now still running because nuclear plants are being switched off instead.

As far as I know that was one of the fears stated, but never actually happened. Do you have any sources stating that coal plants meant to be decomissioned now will run longer?

It is probably also a lot easier for the US to launch a space probe with a nuke power source than Europe.

Regulatory requirements are very different and I am sure the US would not be too happy if Europe where to launch something with a nuke onboard without their approval.

I think putting a nuke on a rocket makes everyone nervous, not just the Americans...

It's not "a nuke", it's a relatively small amount of radioactive material that is sealed inside a very strong capsule designed to survive almost any imaginable catastrophe during launch. The launches are from the coast out over the water. Yes there are still some risks, but in the grand scheme of things, the risks are nothing compared to the importance of exploring the universe.

Not so much easier.

There were demonstrations in America against the launch of Cassini, which is a nuclear RTG-powered spacecraft in orbit around Saturn.

http://www.cnn.com/TECH/9710/04/cassini/

I remember the demonstrations, but they didn't stop it.

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.

Perhaps you have your causation backward: perhaps the mission was planned to last only months due to power limitations.

I was under the impression that they thought the lander would be blown off the comet when it starts to shed ice and debris in large amounts around perihelion.

Philae is a tiny little 100kg add on … 29 times heavier Rosetta (the orbiter) is the main course, Philae is this tiny little and quite experimental (though admittedly extremely cool – mostly because of exactly its novel mission) little hitchhiker.

RTGs are heavy and consequently have pretty much only been used on much heavier spacecraft and even then mostly only when being solar powered just wasn’t an option. For Philae, besides it being very lightweight, being solar powered was and is an option and the only reason it didn’t work out is because things went wrong during the landing …

How in the hell do you even get the idea that Nasa would have used an RTG in ESA’s place here?! They are not psychic. They couldn’t have predicted things going wrong during the landing … and why then put an RTG on this when that’s something Nasa themselves does only very, very rarely and only for very different missions with much more demanding payloads?!

What is this insanity? Why the need to get onto this political pulpit and spew out some unrelated political propaganda because you feel like what? What’s the point of this deliberate and pointless provocation?! Huh? I’m confused and angry at this abundance of irrationality.

RTGs don't have to be heavy and big. Sure one to power a car sized rover like Curiosity with large motors, science equipment, lasers, etc will be big. But one to power a little probe with 24 watts would be tiny. In the 70s there were actually nuclear powered pace makers implanted inside people, so the technology can definitely scale down: https://www.orau.org/ptp/collection/Miscellaneous/pacemaker....

So why doesn’t Nasa use them all the time?

Two reasons. One, in a lot of situations solar power is essentially guaranteed, and when there's no chance that there won't be sun solar panels are a hell of a lot cheaper. Second, there's a plutonium shortage in the US at the moment [1] making it really hard to secure an RTG.

[1] http://www.wired.com/2013/09/plutonium-238-problem/

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... 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 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.

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

"You could fit in an RTG with the same or higher power output as the solar panels for the same mass."

As an expert you should go work for ESA. I'm sure they need you. Oops, armchair space engineer, I forgot. If you need to look in Wikipedia, you have no clue about the subject matter.

Maybe some country, or company, could start a profitable business of launching RTGs and selling them to the ESA after they are safely in orbit?

I wonder how high insurance costs for "launching radioactive isotopes into orbit" are.

How about the PR strategy? "The lander wakes up, we get headlines again!"

</sarcasm>

http://www.popsci.com/nasa-can-make-3-more-nuclear-batteries...

http://www.space4peace.org/ianus/npsm2.htm#2_3

Your links are out of date. The US has since resumed Pu 238 production for use in space-borne RTGs: http://www.economist.com/news/science-and-technology/2164758...

Even if we hadn't resumed production, I'd still be arguing that the simple fix is to resume production and continue using the proven technology, not to simply give up on it.

The European Space Agency together with the National Nuclear Laboratory are looking for a potential use of americium-241 in developing RTGs. So they aren't completely nuke-averse.

http://www.nnl.co.uk/news-media-centre/news-archive/space-ba... http://www.quora.com/How-does-ESA-plan-to-power-its-future-s...

Also, wasn't NASA's Advanced Stirling Radioisotope Generator canned in 2013 due to budget cuts? And recently there were problems with procuring plutonium-238. RTG isn't a silver bullet.

http://www.economist.com/news/science-and-technology/2164758...

"Europe" isn't nuke-averse; French nuclear plant designs are considered among the world's best, and Germany only backed off nuclear power when Fukushima happened.

In light of Fukushima I wish EVERYONE were more nuke-averse...

Germany backed off nuclear power in the 90s long before Fukushima. That process was merely slowed down before Fukushima and set back on track afterward.

This has to also be kept in mind when considering nuclear power in Germany. The nuclear plants in Germany are so old that whether you are pro or contra on nuclear power, shutting down the existing plants is more or less a non-issue.

In light of Fukushima, everyone should be more aware of what happens when you don't properly maintain, and update your nuclear power plants. In light of global warming, and carcenogens released caused by burning coal, I wish every one were more pro-nuclear.

I would add that I hope we all take flood control recommendations more seriously in light of Fukushima, too. I recall that TEPCO knew that it wouldn't withstand a tsunami of that magnitude, and they proceeded to ignore that risk.

> That mission is so far from the Sun that it wouldn't even be possible with only solar panels.

Maybe there's your answer?

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?

Well Rosetta was still operational orbiting the comet and they always hoped that Philae would wake up again, I doubt they would have transferred any significant number of people to other projects.

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.

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.

>This is potentially the space mission of the Century.

I would really hope it isn't.

space mission of the Century , so far...

A livestream from a comet, with a 24W power budget?

Depends on your definition of stream...

http://isee3.p3s.nl/philae/

So 40 minutes ago the main structure was at +9.17C. Not exactly high def video but still kinda cool.

Please don't "hacker news effect" the poor server. But yeah, live streaming data...

Either the battery's temperature sensor is malfunctioning, or Philae somehow managed to achieve temperatures far below absolute zero. :)

The maximum transmission window has been 84 seconds from Philae to Rosetta.

Only the Rosetta sensors are 'live' - contact with Philae is still intermittent - they don't know where it is and the German team with the Hi-Res camera is refusing to release the photos of the surface that could potentially reveal Philae's location.

http://isee3.p3s.nl/philae/

From the file cache it is observed that Philae woke up 3 days ago but they may were looking in the wrong place and missed it.

Radio telemetry could locate it but aligning Rosetta's antennae and flight path with the mouth of the crevasse or cave where Philae is wedged has only resulted in a few intermittent transmission mostly only 10s of second long so not enough to download anything or issue new orders.

When enough glimpses have been received triangularion may be possible - but the CONSERT radio signal is designed to penetrate 67P.

Precise location triangulation proved impossible in the days CONSERT was operational before Philae's hibernation.

Full resumption of Philae is not assured at this stage.

67P grows ever more volatile as Perihelion fast approaches.

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.

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 :)

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...

Nice music, too ;)

  "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...)

Will the heat affect the lander's measurements?

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.

Awesome book!

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

Absolutely awesome.

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

Was this intentional hibernation?

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.

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

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.

They had confirmed that it had landed a bit rough.

It hasn't flown back, but the comet has moved and is now closer to the Sun, so there is more light for the lander.

The bouncing did not mean, that it went off the comet. It just landed very roughly and ended up in a place next to a wall with little exposition to sunlight.

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

YESSSSSS!!!!

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

http://xkcd.com/1446/

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!

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