OT Rosetta arrives at comet

[miguelvp]

And suddenly the image of mega maid from spaceballs came to mind

[T3sl4co1l]

Comets kind of are just cosmic dustballs...

Tim

[i4004]

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.

some folks have a saying that two man know more than one....hehe...those working should listen to those on the shores, from time to time they'll get good suggestion.
and, thus far, i just love the "experience argument" which seems to be all-encompassing many times in human conversations overall...

experience didn't exist prior to this, yet they did it somehow, how come? 
experience seems a bit outdated in these times when you can learn to solder just by watching yt...and frankly, i find that not a bad thing...it's not important how you learn it, it's important to learn it.
esa learned quite a bit from this mission i would imagine.
i learned it takes too much damn time to go there! 
also, imagine you work on something for 10 years and it flops once there....
they shouldk of made 2 completely different systems, just incase one failes.
and if they made 3, then they could do anything!   
(each system would have 2 probes!)
i mean if you wanna spend money in that way, spend it!

here's an interesting thought: how much better would the same thing be today, knowing how much things improve in 10yrs, esp. in electronics.
perhaps it could include a cpu fast enough to deploy hooks at time? 
(sorry, can't resist! i mean the thing was obviously slow if it bouned few times off the comet)

perhaps they could think of a way to launch hooks first, like a harpoon....and aim for the brightest spot on the comet, not the best shade! 

Will there be any possibility of adjusting the landing sequence once it is initiated?
No. Once the landing sequence has been defined (release speed, position for release etc.) and initiated, it will not be possible to adjust it. However, it should be recalled that the lander will be released at a height of about 22.5 kilometres from the centre of the comet and will touch down on the comet at walking speed, minimizing the risk of an incident.

What if the lander touches down on a very steep slope and drills itself into an awkward angle, or sinks into porous snow or some other soft material?
The lander is designed so that it can land on a slope of up to 30 degrees. The feet are equipped with large pads to allow the lander to touch down on a soft surface. If the surface is very soft, the lander’s feet may sink into it but sinking will eventually be stopped by the bulkiness of the lander’s body. In all scenarios, the lander is expected to be able to safely transmit its data.

http://www.esa.int/Our_Activities/Space_Science/Rosetta/Frequently_asked_questions

did anybody even think about possibility that sun would be shaded on some places on the comet, i wonder...perhaps the panls shoudl be om the harpoon to launch them anywhere near? 

gosh, how succesfull would the mission be if we had to comment it 10 years ago! wooohoooo!
 

[Howardlong]

While working on a project at ESA some years ago, a few of us had an impromptu space soldering course which was an eye opener. There are guys there where that's all they do, professional space solder dudes.

There were plenty of things to think about, most notably when soldering down wires to lands on boards, once the wire had been stripped (there was an expensive and underused machine to do this, you program in that you wanted, say, 50 x 23.6cm lengths of wire, and it would cut and strip them for you precisely, just moments later), after soldering the stripped end, a short loop was made a few mm long and the teflon insulation was glued down with special glue to the board. This was to mitigate against vibration during launch. All solder is full fat of course. You could then crimp the other end with a $1000 crimping tool for the D connector.

We also could only cycle SMA connectors once on flight hardware, of course that was with a $500 SMA torque wrench while wearing fetching dinner lady outfits and sweaty blue plastic gloves. Connectors were replaced after that one cycle. In contrast, I have a test fixture for one of my non-space designs that uses SMA connectors. I use a half turn SMA saver test connector to avoid having to reterminate the SMA on the test fixture. Those saver test connectors last around 6000 cycles before they need replacing. When you look at the pin of a 6000 cycle SMA connector, you can see that it's gradually been worn down by the abrasive effect of plugging it in and out.

Almost everything is conformally coated, but some RF stuff doesn't work too well with all that gunk on it and is left alone if you can pursuade them. Part of the reason to do this is for vibration, and part is to control outgassing.

[i4004]

and is left alone if you can pursuade them. Part of the reason to do this is for vibration, and part is to control outgassing.

what, prevent pros from adhering to their standards?
come on, that can't be possible!
 

as for "space soldering" whiskers fenomenon is interesting
http://nepp.nasa.gov/whisker/
http://en.wikipedia.org/wiki/Whisker_%28metallurgy%29#Effects
although it exists on earth too...

[Howardlong]

There's a process you can do to re-tin ROHS COTS parts to mitigate against tin whiskers. It's potentially a big problem as parts get smaller. That's also the main reason that aerospace stuff doesn't use diet solder.

There are a number of good reason to use COTS rather than specially designed devices in space applications, it's not just cost. One is that COTS parts, made in high volume, are well characterised, in contrast to very low volume devices.

You can mitigate against things like outgassing as well as total dose and single event effects when using COTS parts to some extent, but again, the continuing miniaturisation doesn't help with transistor gate insulation gaps becoming smaller and smaller. In some scenarios, particularly orbiting within the van Allen belts, the effects of radiation are greatly reduced.

[Howardlong]

did anybody even think about possibility that sun would be shaded on some places on the comet, i wonder...

Yes, they did, they chose a spot free from rocks and with maximum solar visibility, but as we now know it bounced a few times and landed in an unplanned location.

[PA0PBZ]

It's awake! 

[EEVblog]

It's awake! 

 
Exciting!

[benst]

It's awake! 

 
Exciting!

+1E9

[Howardlong]

It's the lead story on the BBC website in the UK at the moment. Who says space is boring?

24W of power available, I guess that's solar and not WiFi or ultrasonic powered. 

Somewhat reminiscent of the AO-7 satellite that remained dormant for 21 years, until a shorted battery became open circuit after years of attempted recharge cycles. It remains functional for two way voice communication, when not in eclipse, to this day.

[rr100]

Outstanding!

Go, Philae, go!

[Kjelt]

What an incredible fast service repair team ESA have 
Now lets wait what exciting stuff the data has in store for us 

[Fraser]

I was so pleased to just read that Philae has managed to charge her batteries and phone home.

Yay 

I only hope it doesn't get too rough up there with the suns rays melting ice. It would be a real shame if she got dislodged after surviving to data.

At this point I should admit that, as a child, I was quite sad when researching the various Roving Probes that had been sent to the moon. I hated the fact that they 'died' or were shut down and abandoned up there    Daft I know but I actually cared about the probes !

https://en.wikipedia.org/wiki/List_of_lunar_probes

My favourite was the Russian Lukokhod (meaning moon walker) rover and she was Nuclear heated

https://en.wikipedia.org/wiki/Lunokhod_programme

https://en.wikipedia.org/wiki/Lunokhod_2

Who else watched the live TV coverage of Giotto's approach to Halley's Comet in 1986? Her debris shield got pelted badly and she was 'blinded' ... I was really rooting for her and was so chuffed that she survived the encounter.

Uh-Oh, the men in white coats have just turned up outside the house.......

[TerraHertz]

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

Rosetta photo set.
Note there are 6 pages of pics. Index is at the bottom of the loooong pages.

[PA0PBZ]

They found the little bugger!



https://twitter.com/ESA_Rosetta/status/772803496420704256

https://twitter.com/esascience/status/772804570598760452

[Fraser]

Great news.

Some more comment on the search and Rosetta's final mission task here....

http://m.esa.int/Our_Activities/Space_Science/Rosetta/Philae_found

Fraser

[Kjelt]

Just a side thought, is there no other way to get energy besides sunpower when sitting on an asteroid ? 
It is such a waste that a bit of shade makes an apparatus travelling such a huge distance succesfully, totally useless in the end  .

[Gyro]

Agreed, a great shame but not a total loss. It did manage three days of science before the batteries went flat and locating it has added some very useful context to the measurements it did manage.

http://www.bbc.co.uk/news/science-environment-37276221

It looks as if Rosetta is destined to join it in a few weeks time, though a little more violently.

[T3sl4co1l]

Just a side thought, is there no other way to get energy besides sunpower when sitting on an asteroid ? 
It is such a waste that a bit of shade makes an apparatus travelling such a huge distance succesfully, totally useless in the end  .

RTGs are expensive, and Pu238 is at a bit of a shortage right now (Juno's entirely solar powered, despite being in the outer solar system!), so they probably took that risk in relation to other options or costs.

Tim

[SeanB]

Pu238 is around in large quantities, just that there is no incentive to set up the reprocessing facilities to get it out of the spent PWR fuel rods that are sitting around in ton lots in reactor storage ponds.

[T3sl4co1l]

No, that's Pu244 (and a little Pu239).  Pu238 is made from Np:
https://en.wikipedia.org/wiki/Plutonium-238#Production
Well, it's still present... but separating Pu isotopes sounds awful.  Better to chemically separate, then transmute..(?!)
Repro in the US is a big deal/problem, though.  Well, not really a problem, in and of itself, but it probably will be in the semi-near future.

Tim