Rosetta & Philae

[Eclipse]

News stories as of writing this are that the separation and landing were successful, no surface  imaging yet.

http://www.esa.int/Our_Activities/Operations/Live_updates_Rosetta_mission_comet_landing


Roestta snapped from Philae after separation

Landing on a Comet - ESA's Rosetta Mission

Highlights: Rosetta mission comet landing up to lander separation

[Майор Хаткевич]

Not quite as exciting as humans on other bodies, but probably one of the more exciting things of my short life.

[a2capt]

There's reports of the harpoon system not firing.. though this was a drill down and then capture.

Lets hope it's not like a nuptial flight ... .. and the little guy hangs on...

[Eclipse]

http://www.youtube.com/watch?v=6sk5IuIjr1E#

[JeffDG]

I just wish the news would stop saying they landed on a "moving comet".

I just jumped into the air.  And you know what?  I landed on a moving planet!  Heck, if you jump a meter in the air, the Earth moves 26.8km while you're in the air!

Heck, I have a 2 1/2 hour flight scheduled for Friday...I'll land on a moving planet then too...while I'm airborne, the Earth will move over 167,000 miles.

[PHall]

I just wish the news would stop saying they landed on a "moving comet".

I just jumped into the air.  And you know what?  I landed on a moving planet!  Heck, if you jump a meter in the air, the Earth moves 26.8km while you're in the air!

Heck, I have a 2 1/2 hour flight scheduled for Friday...I'll land on a moving planet then too...while I'm airborne, the Earth will move over 167,000 miles.

So what's wrong with what they're saying?  Factually, they're correct.

[SarDragon]

It's all about frame of reference.

When you jump on the big blue marble, you are still moving through space at the same speed, and have no sensation of that movement.

When landing the probe on the comet, the two objects are moving through space at different velocities, and making the connection is much more complicated, and difficult, then just landing back on the big blue marble after jumping into the air.

Jeff - "Lighten up, Francis."

[Eclipse]

http://www.esa.int/spaceinimages/Images/2014/11/Welcome_to_a_comet

ESA is still trying to locate where on the comet it is sitting, it is sending intermitent telemetry due to the spin of the
comet. It bounced on impact back into space for two hours, then settled back down.  It may be in a crack or ravine, which is causing concern
for power budget.


http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/11/welcome_to_a_comet/15048351-1-eng-GB/Welcome_to_a_comet.jpg

[PHall]

When you jump on the big blue marble, you are still moving through space at the same speed, and have no sensation of that movement.

That's because it's all relative...

[SarDragon]

Remember, you can pick your friends, but you can't pick your relatives. 

[JeffDG]

When you jump on the big blue marble, you are still moving through space at the same speed, and have no sensation of that movement.

Same thing with the comet.

They spent years getting into position and going at the same speed as the comet.

[Luis R. Ramos]

I do not think that would be possible.

Otherwise, why the anchors? Why did Philae bounced two feet?

You still have to account the lander is firing rockets that may or may not be controllable enough.

The only way both could have been at the same speed is if Philae would have been on it to begin with.

[sardak]

They spent years getting into position and going at the same speed as the comet.

I do not think that would be possible.

You still have to account the lander is firing rockets that may or may not be controllable enough.

Otherwise, why the anchors? Why did Philae bounced two feet?

From the European Space Agency description of the system: "Immediately after touchdown, a harpoon is fired to anchor the Lander to the ground and prevent it escaping from the comet's extremely weak gravity." It bounced for the same reason that things bounce and tumble on Earth, but more so because of the weak gravity.

The only way both could have been at the same speed is if Philae would have been on it to begin with.

Really? How do we land spacecraft on other planets or the moon? The principle is exactly the same as landing on the comet, but planets and the moon provide a bigger target and more gravity. The same principle as to how the Space Shuttle retrieved satellites from orbit. It wasn't by sticking out the orbiter arm and snagging them like a fly ball whizzing by. The same principle is how spacecraft rendevous in space. It's not because they all started on Earth. It's relative speed and if the target's big enough, orbital velocity.

Mike

[Eclipse]

Comet from 40 meters:


First touchdown:


First (and maybe last?) panoramic:


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