OT Rosetta arrives at comet

[tinhead]

 

[Homer J Simpson]

Congratulations to all of those involved. Outstanding achievement.

These are the types of things that inspire a new generation of kids to be scientists and engineers.

The pride in the faces and words of those evolved  is well deserved.

 
 

[Alexei.Polkhanov]

First broken thruster, then harpoons that did not work  Does not sound very "inspirational" to me. I hope they can trace the problem back to its origin whoever or whatever it is.

[bitwelder]

For those who missed the event, the landing sequence in 136+ steps by Randall Munroe:
http://xkcd1446.org/

[miguelvp]

First broken thruster, then harpoons that did not work  Does not sound very "inspirational" to me. I hope they can trace the problem back to its origin whoever or whatever it is.

After a 10 year trip in space and actually doing a successful landing I don't see why it wouldn't be inspirational.

[KJDS]

First broken thruster, then harpoons that did not work  Does not sound very "inspirational" to me. I hope they can trace the problem back to its origin whoever or whatever it is.

It was designed in the 90's, using 80's technology. Whoever chaired the design reviews will now be retired. Procedures for running the reviews will have changed significantly and the probability of working out exactly why things didn't work perfectly is remote.

No-one will get blamed for it, for the moment you start blaming people for mistakes is when they stop taking risks, and it would be a very dull world without risk.

[Monkeh]

First broken thruster, then harpoons that did not work  Does not sound very "inspirational" to me. I hope they can trace the problem back to its origin whoever or whatever it is.

It's the first time we've ever sent a lander to a comet. You expected it to go perfectly?

[Royce]

On the DLR stream (but not the ESA stream) they indicated that they suspect the lander bounced off and then landed again. They got some indications that the lander began rotating after landing but after while the rotation just stopped.

Hopefully the radio link comes back as expected when Rosetta comes back up over the horizon for the lander. I want to see some super close in pics!

[Alexei.Polkhanov]

First broken thruster, then harpoons that did not work  Does not sound very "inspirational" to me. I hope they can trace the problem back to its origin whoever or whatever it is.

It's the first time we've ever sent a lander to a comet. You expected it to go perfectly?

That is absolutely not true - Japanese Space Agency tried it first 11 years ago:  http://en.wikipedia.org/wiki/Hayabusa.

[PA0PBZ]

That is absolutely not true - Japanese Space Agency tried it first 11 years ago:  http://en.wikipedia.org/wiki/Hayabusa.

http://www.diffen.com/difference/Asteroid_vs_Comet 

[Alexei.Polkhanov]

Well if you take the orbital period then 67P falls under meteorite, (Orbital period (years) 1-100 for meteorites vs 75 to 100,000++ for comets) plus its orbit is not as eccentric as most of comets. I am not sure if dusty/soft surface of a comet vs meteorite makes it more or less challenging to land on. Obviously we can argue forever here - comet or meteorite or something in between like planet or dwarf planet - and what would be the point?

[i4004]

what (radio) modulation scheme do they use on these things(?), that data is not that easy to come by on the web, it seems...

i see this
http://www.brighthub.com/science/space/articles/116036.aspx

but that's kinda inconclusive and vague (pcm in itself has nothing to do with radio)..and this

http://deepblue.lib.umich.edu/bitstream/2027.42/6820/5/bac9829.0001.001.pdf

is rather old...1956

pcm-am is mentioned in that old paper....

[Alexei.Polkhanov]

There is whole book on subject: http://www.amazon.com/dp/0471445363/ref=rdr_ext_tmb
Books are publicly available from NASA website here: http://descanso.jpl.nasa.gov/monograph/mono.html

[Howardlong]

what (radio) modulation scheme do they use on these things(?), that data is not that easy to come by on the web, it seems...

Almost certainly it will be a PSK based scheme, this has been the standard for decades for space telemetry due to link budget efficiency, together with a FEC coding scheme, and almost certainly it'll be using CCSDS standards.

http://public.ccsds.org/publications/BlueBooks.aspx

[Howardlong]

Here you go:

http://www.esa.int/esapub/bulletin/bullet95/CALZOLARI.pdf

Popping "CCSDS" and "Rosetta" into Google generated a number of other good results too.

[rs20]

First broken thruster, then harpoons that did not work  Does not sound very "inspirational" to me. I hope they can trace the problem back to its origin whoever or whatever it is.

It's the first time we've ever sent a lander to a comet. You expected it to go perfectly?

The trouble is, the failures weren't really comet-specific -- explosive in the harpoons going lame in the vacuum of space? Nothing to do with comets. The thruster completely failing? Nothing to do with comets.  I'd completely agree with your comment if it landed and, I dunno, it cracked the surface and got launched up by a jet of gas or something; or if the harpoons failed to grip the unknown material of the comet. These are "first time we tried it"-relevant excuses. It appears the reality isn't quite as easy to dismiss.

On the other hand, they seem to be saying that the mission will be 90%+ successful from a scientific standpoint, so it's all good.

[Kjelt]

I bet you guys build way better and sturdier space exploration ships all the time. We have a saying in our country: the best helmsmen are standing on the shore, meaning the people always commenting on others without having any or little experience themselves always seem to know better or claim to do it better.

[rs20]

I bet you guys build way better and sturdier space exploration ships all the time. We have a saying in our country: the best helmsmen are standing on the shore, meaning the people always commenting on others without having any or little experience themselves always seem to know better or claim to do it better.

Yes, a nice, albeit vague saying. But what I ask you is: if an organisation that makes thrusters is asked to make a thruster, is it not reasonable to expect that thruster to work, or be at least vaguely critical if it doesn't, jeopardizing a billion dollar project? Same for explosives that just have to go "pop" after being in space for a while. This should be a solved problem, there are many many pyrotechnics that have worked fine after years in space.

[KJDS]

I bet you guys build way better and sturdier space exploration ships all the time. We have a saying in our country: the best helmsmen are standing on the shore, meaning the people always commenting on others without having any or little experience themselves always seem to know better or claim to do it better.

Yes, a nice, albeit vague saying. But what I ask you is: if an organisation that makes thrusters is asked to make a thruster, is it not reasonable to expect that thruster to work, or be at least vaguely critical if it doesn't, jeopardizing a billion dollar project? Same for explosives that just have to go "pop" after being in space for a while. This should be a solved problem, there are many many pyrotechnics that have worked fine after years in space.

Having done a fair bit of designing for satellites, it's very likely that they were using technology that had been used on previous missions. Heritage is everything and nothing new is included without very good reason.

[zapta]

We have a saying in our country: the best helmsmen are standing on the shore.

Here it's called 'monday morning quarterback'  (or to paraphrase your saying:  the best quarterbacks are on the couch).

Overall the goal and the technical achievements look very impressive to me.

[Dave Turner]

What will be more interesting is to see whether the team are able determine what caused the failure. Trite statement or not such information will be useful for the future. Wonder whether there is anything in the data so far to aid diagnosis.

[Howardlong]

I bet you guys build way better and sturdier space exploration ships all the time. We have a saying in our country: the best helmsmen are standing on the shore, meaning the people always commenting on others without having any or little experience themselves always seem to know better or claim to do it better.

Speaking for myself, I have half a dozen spacecraft orbiting the planet right now that I had a direct hand in, and three more in development. Does that count? ;-)

I've had my fair share of problems in the projects I've worked on, plenty of battle scars believe me, some that would make your retrospective toes curl. But we learn from those mistakes. It goes with the turf.

[lapm]

I think its just huge thing that they can take old proven technology and turn it into spacecraft. kick it out of atmosphere, let it pretty much freeze up for few years and its still mostly works after that time.

About that thruster that did-int work, all it takes is small micro meteorite hit to damage cable or something in right spot to prevent it firing.. If that's the only problem that machine after being 10 years in space, that's good...

[Kjelt]

Well just look at the blunders made with the european gps satelites this year, two came in the wrong orbit due to a probably russian software failure. Look how many times this had already been done succesfully , tested and still some error occurs, now if you make a comment about that I would partially agree, this should not happen unless an accident occurred.
But still it did and often does which tells me this is science at the cutting edge, they don,t call it rocket science for nothing.
But this mission was even more unique, a one of a kind, the thing has been out there for ten years and travelled 6.4 billion kilometres , the rendez vous was a succes and they even landed the lander on the comet with some glitches yes. Two things did not work, out of, what? two thousand things that could have gone wrong? They gave it a 50% chance from the get go.
No I can only be very silent on this achievement in awe what they did achieve and so are other space organisations that congratulated ESA on this achievement. 

[Dave Turner]

Given just the known scrap orbiting the planet it's becoming a bit of a lottery just getting to outer earth orbit.

http://www.space.com/16518-space-junk.html

Just perhaps funding could be found to try out one of the many proposed 'vacuum' sweepers  to deal with the problem. I'm sure that would lead to many new discoveries.

Perhaps Dyson could be consulted!