Rosetta ends its mission

http://www.bbc.co.uk/news/live/science-environment-37499184

by pcrh • 10 years ago

296 61 10 years ago

bbc.co.uk

Our little trouble seem so tiny, when you see something like https://pbs.twimg.com/media/Ctk7stYWEAA10jf.jpg:large and ponder on one of our vessel landing on there.

(Don't astronauts feel a very strong version of this when they look back at the blue globe from space?)

asimuvPR3• 10 years ago

I felt something similar while using a VR headset with space simulator. It really changed me.

daedecai• 10 years ago

Can you expand on this experience?

sixdimensional• 10 years ago

I would like to experience this. Could you elaborate - what space simulator was it and which VR headset? Thank you!

cheeseprocedure• 10 years ago

"You develop an instant global consciousness, a people orientation, an intense dissatisfaction with the state of the world, and a compulsion to do something about it. From out there on the moon, international politics look so petty. You want to grab a politician by the scruff of the neck and drag him a quarter of a million miles out and say, 'Look at that, you son of a bitch.'"

-- Edgar Mitchell, Apollo 14 astronaut

jankeromnes• 10 years ago

GMT is deprecated, please use UTC instead: "GMT is no longer precisely defined by the scientific community" - https://en.wikipedia.org/wiki/Coordinated_Universal_Time

arethuza• 10 years ago

To be fair it is a BBC site - if they started reporting times in UTC then it would just confuse the vast majority of their readers.

lucideer2• 10 years ago

This may be true generally, but given the subject of the article this would be an ideal pilot for a gradual changeover

lovemenot• 10 years ago

> The moment of flatline in the control room is still expected at 11:18 GMT; 12:18 BST; 13:18 CEST +/- 2min

If the BBC's Science Correspondent had mostly been concerned with not confusing the vast majority of users, they'd have quoted the time of descent in BST first and qualified it with GMT and others. Instead they gave their preferred "standard" time first and then qualified it with a daylight savings time that is currently relevant to the vast majority of the BBC's readers.

willvarfar• 10 years ago

Trying to tell the Brits not to use GMT is like trying to tell the HN audience that there are exactly 1000 bytes in a kilobyte ;)

_asummers• 10 years ago

Or getting Americans on the metric system.

csmattryder• 10 years ago

As a Brit who's spent the last few months arguing with Windows 10 about just what time it is - for the love of all that's holy people, save us from GMT/BST.

UTC is for life, not just for summer.

Someone• 10 years ago

You may complain to the editor if the scientific papers coming out of this use GMT, but this isn't aimed at the scientific community; the story in the #1 spot on http://www.bbc.com always aims for a way broader audience.

JackFr• 10 years ago

I don't get the downvotes. This is precisely the kind of pedantry for which I come to HN.

Symbiote2• 10 years ago

Perhaps because of the misleading partial quote from Wikipedia.

The full sentence is "For most purposes, UTC is considered interchangeable with GMT, but GMT is no longer precisely defined by the scientific community."

The ESA website gives all times for the descent ±20 minutes, so GMT, which is ±0.9s from either UTC or UT1, is fine.

kijin• 10 years ago

Instead of arguing about this ad infinitum, we should just collectively execute

    ln -s UTC GMT

and call it a day. It wouldn't break backward compatibility with anyone's usage, would it?

mino• 10 years ago

I found this FAQ very informative:

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

Also, the per-instrument bitrate breakdown for the last minutes:

http://blogs.esa.int/rosetta/2016/09/28/science-til-the-very...

Goodbye Rosetta!

wbhart• 10 years ago

They apparently got photos down to 5m (or maybe only 51m) above the comet. Here are images on the way down.

https://www.cieletespace.fr/actualites/dernieres-images-de-r...

https://twitter.com/C_et_E_Photos/status/781809777370423296

https://twitter.com/ESA_Rosetta/status/781808178048696321

https://twitter.com/elakdawalla/status/781809255443673088

https://twitter.com/C_et_E_Photos/status/781819361241817088

https://twitter.com/ESA_Rosetta/status/781825922647355392

https://twitter.com/elakdawalla/status/781834822583017472

eric_h• 10 years ago

just wanted to add that I highly recommend following @elakdawalla on twitter - she tweets lots of great things about the various space missions that are in progress.

IndianAstronaut• 10 years ago

To follow up, the organization she works for, The Planetary Society, does fantastic work to promote greater funding for space research and missions.

idlewords• 10 years ago

She is an absolute treasure. Her longer-form blog posts are also fantastic reading http://www.planetary.org/blogs/emily-lakdawalla/

ljf• 10 years ago

I've only been following this news very lightly - but it is fascinating. This gave me more detail on the 'why' it was being crashed: http://www.telegraph.co.uk/news/0/rosetta-mission-what-is-it...

xgbi2• 10 years ago

I'll know rosetta has "landed" when the XKCD has been updated: https://xkcd.com/1446/

mnw21cam• 10 years ago

And indeed, it has: http://xkcd.com/1740/

TuringTest• 10 years ago

And Earth is saved!

3chelon5• 10 years ago

Can anyone explain why they would (a) crash, rather than attempt to land the probe on the comet's surface, and (b) turn the power off at the moment of touchdown?

Everything I've read (admittedly, not much) says they will get more data from crashing it, but that makes no sense to me. Surely landing it as intact as possible and leaving it running means it could send data whilst it has any remaining power, and maybe again in the future whenever it gets enough sunlight? Even if it was just a semi-intact archaeological curiosity for future generations, surely that would be better than wilfully destroying it?

gjulianm• 10 years ago

I'm not sure about (a), but it would probably be very difficult to land it with the thrusters on the probe. Philae almost bounced off the comet and it was designed for that purpose...

For the second one, seems that https://twitter.com/AstroKatie/status/781814758404005888 has the response (with not a lot of details).

Symbiote2• 10 years ago

From the ESA FAQ

"As soon as Rosetta hits the surface, its main systems will be turned off, including the attitude and control systems, as well as the main transmitter, the latter in order to meet regulations aimed at avoiding interference on deep space network communications channels"

"as soon as Rosetta hits the surface, its high-gain antenna will very likely no longer be pointing towards Earth, making any potential communications impossible"

"One of the key features of the trajectory design is to minimise the spacecraft's relative velocity at impact. The current scenario predicts that the impact velocity will be around 90 cm/s, around walking pace."

I recommend reading the whole FAQ, it's very informative.

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

3chelon5• 10 years ago

Useful info, thanks. So it's more of slo-mo crash landing then - that makes much more sense now. And the bit about the directional antenna also makes total sense.

3chelon5• 10 years ago

And of course, they can't turn it off after they've touched down because they will likely no longer have a comm link!

xgbi2• 10 years ago

I didn't read on, but my guesses:

- batteries will die when cold, they can't reanimate the probe when it comes back from the large ellipse of its orbit - probe has orbited the comet for 2 years, and has seen the most important period (closest to the sun). There's not much to learn from more pictures of that far away - landing would not work (no landing legs, not enough gravity, see Philae), and the camera is not made for it. - at the speed of impact (walking pace), it won't be crushed entirely, and will probably bounce a few times before settling on the comet. Philae is already there BTW, so that's an artifact.

3chelon5• 10 years ago

Good call about the batteries - of course they will become totally useless after discharging and freezing.

JulianMorrison• 10 years ago

They "crashed" it at a walking pace, at worst it's a bit twisted, definitely still an archeological curiosity. Why do that? Probably to try to get close-approach data that the detachable probe failed to. Why crash? I don't know if the vehicle even has the capability to retro-thrust itself to a stop but trying would be a fiddly maneuver and would likely mess up the science (puffing up an opaque cloud of dust, blasting the landing site). So approach-and-keep-going makes sense. But then the vehicle will lithobrake with predictable smashy consequences. So it's toast one way or the other; turning it off is probably just tidiness.

All the above is guesses but seems to make sense to me.

datenwolf• 10 years ago

…lithobrake…

Thanks for adding this to my vocabulary.

pavel_lishin• 10 years ago

definitely still an archeological curiosity.

I was going to say that it'll probably get blown off when Churyumov-Gerasimenko nears the sun, but it's already done that, and Rosetta taught us that a comet isn't just a boring spherical ice-cow that outgasses equally in all directions anyway.

Maybe it'll survive to make another pass near the Earth! Maybe SpaceX will "rescue" it as a PR mission in the next few decades. It would make a pretty great addition to the Air and Space museum.

mirimir• 10 years ago

... lithobrake ...

OK, can't resist: https://www.youtube.com/watch?v=yeaeqIpopvI

TorKlingberg• 10 years ago

Basically, Rosetta has a highly directional antenna, and there was no chance it would still be pointing towards earth after landing. So they programmed it to switch off the transmitter on landing to avoid causing interference for other missions.

It "crashed" into the comet very slowly, so it was not smashed to pieces. It may be have bounced back and will eventually land somewhere else. We may never know.

david-given• 10 years ago

As an addendum to that, people might find this interesting:

https://en.wikipedia.org/wiki/Galaxy_15

The tl;dr is that Galaxy 15 is a massive two-tonne geostationary communications satellite around Earth; in 2010 it went mad and started broadcasting hash. It basically became an uncontrolled jammer. It drifted out of its slot in geostationary orbit and started passing near its neighbour satellites, wreaking havoc. Several had to be moved to get them far enough away from Galaxy 15 to prevent interference.

Eventually, after about a year, its batteries went flat and it rebooted, and started responding to commands again. After checking out it was put back into its orbital slot and I believe it's still in service today.

thewavelength• 10 years ago

I wonder why they uploaded a special software which disallows any communication prior to the impact [1]. Why don't they just let Rosetta impact and have a look if it still works? Why is it necessary to shut it down to disallow command instructions from earth?

[1] http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rose...

pducks32• 10 years ago

The antenna is incredibly strong (or would be if it got some sunlight) so it's important to not interfere with communications in deep space that we may want in the future and even sensors on earth. These scientists—I imagine—fell in love a long time ago from staring at the deep beauty of space; it'd be quite a shame if we drowned it out with our petty no-longer-useful noises.

Stratoscope• 10 years ago

I love Paul Coxon's tweet of the Rosetta mission told in emoji:

https://twitter.com/paulcoxon/status/781785896513314816

sandworm101• 10 years ago

Wait a second. With every other probe or rover story the experts talk about how there is no "shutdown" command, that there is no need and that having one only creates a risk of inadvertent use.

Is this just PR to cover the fact that this probe will be sitting alone in the dark but still 'alive' should it get enough power? See https://xkcd.com/695/

flinty• 10 years ago

feel strangely emotional about the end of the mission :(

Rosetta ends its mission

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