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Rosetta, Philae and Comet 67P/Churyumov-Gerasimenko.

Vicomt

By Vicomt
in Science & Spaceflight

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Kryten

Kryten

Posted
Posted
Are they planning to put the probe into a polar orbit, so that it doesn't get sprayed so often?

I'm not sure that'd even be possible. It's not exactly a very regular shape, and orbits are going to reflect that.

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Sky_walker

Sky_walker

Posted
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Here is the orbit shape - first probe will follow "triangular orbit" making burns at each "corner", and then enter classical, elliptical orbit.

Here is more detailed description: http://blogs.esa.int/rosetta/2014/08/01/how-rosetta-arrives-at-a-comet/

Random relevant quote:

Once Rosetta arrives at comet 67P/C-G on 6 August it will travel along a series of three arcs at an altitude of 100 km slightly ahead of the comet with respect to the Sun, subsequently repeating this triangular shaped trajectory at an altitude of 50 km, all the while assessing the comet’s behaviour and learning how to operate in uncharted territory.

These manoeuvres will be controlled by thruster burns, then, once at an altitude of about 30 km, the comet’s own weak gravity should be able to keep Rosetta in orbit. Depending on the activity of the comet, the aim is to orbit even closer, perhaps as close as 10 km.

Edited by Sky_walker
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sndrtj

sndrtj

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Posted

I remember being at the ESA open day in Noordwijk 2 years ago. They had a model of Rosetta on display. It surprised me how much stuff they managed to cram in what's basically a desk-sized box. It's tiny. I'll see if I can find some pictures of it.

On another thing... Could Rosetta be used to nudge the comet in a slightly different orbit? If case I recall correctly, gravity assists actually exchange orbital energy, which in the case of planets is so utterly tiny to be unnoticeable for many thousands of assists. But a comet is far smaller, much less mass, so a single gravity assist will have bigger effect?

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vger

vger

Posted
Posted
note the nucleus is horribly overexposed, and it's covered with cosmic ray flashes due to the long exposure time. Even with that, it's only visible to maybe 50km out at either side, compared to tens of thousands for something like Halley.

Ah, thanks for that. Of the blogs I've been following, I haven't seen that image before. Hopefully the comet will start 'performing' when it nears the sun. I vaguely remember it being much brighter a few months ago and then it suddenly fizzled to the state it's in right now.

Here is the orbit shape - first probe will follow "triangular orbit" making burns at each "corner", and then enter classical, elliptical orbit.

Wow... that's about the most complicated thing I've ever seen. Why the sudden reverse from counter-clockwise to clockwise orbit at about 0:35?

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Streetwind

Streetwind

Posted
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On another thing... Could Rosetta be used to nudge the comet in a slightly different orbit? If case I recall correctly, gravity assists actually exchange orbital energy, which in the case of planets is so utterly tiny to be unnoticeable for many thousands of assists. But a comet is far smaller, much less mass, so a single gravity assist will have bigger effect?

This isn't like a small asteroid similar to the ones NASA is eyeing for the ARM mission. 67-P-CG is the size of your average mountain. I think I've seen figures like 4 kilometers across. While they have yet to determine its mass, rest assured that no amount of gravity tractoring on Rosetta's part will do anything noticable to this comet's orbit. In KSP terms, think of something like a few hundred E-class asteroids at once.

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vger

vger

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15 hours 15 minutes till arrival.

Live transmission from the event will be available on http://rosetta.esa.int/

Well this is disappointing. Unless they just didn't announce the schedule, there's no indication that NASA TV will be running anything, which means I can't even record this.

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WeirdCulture

WeirdCulture

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Well this is disappointing. Unless they just didn't announce the schedule, there's no indication that NASA TV will be running anything, which means I can't even record this.

well yes... esa not NASA. I think you can watch it afterwards, because this will be recorded anyway :)

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Sky_walker

Sky_walker

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Wow, for once I will be able to catch the live stream of something. Anyone else watching?

Yep :)

Latest news from ESA:

Orbit entry burn programmed start is 11:00:01CEST on board. Confirmation will come via telemetry only 22min:29secs later
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Sky_walker

Sky_walker

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And we have a burn :)

It'll last ~6 minutes, in 22 minutes after that we should get a signal back with telemetry.

This afternoon we should have some pictures from the OSIRIS high-resolution camera.

lol@the elder guy - "this is a very high precision instrument, not an Opel or Fiat"

14835451282_51dac66d2d_m_d.jpg

Edited by Sky_walker
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Sky_walker

Sky_walker

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"Hello Comet" in all of the ESA-members languages:

Bongu, kometa!

Labas, kometa!

Sveiki, komēta!

Tere, komeet!

Ahoj kometa!

Helló, üstökös!

Pozdravljen, komet!

Moïen, Koméit!

Dia dhaoibh uilig ar cóiméad!

Γεια ÃοÅ, κομήÄη!

Salutare, cometă!

Ahoj kometo!

Witaj, kometo!

Hej, komet!

Hei, komeetta!

Hallo, komet!

Hallo, komeet!

Olá, cometa!

Ciao, cometa!

Salut, comète!

Hola, cometa!

Hallo, Komet!

Hello, Comet!

Pretty much every single ESA country contributed something to the Rosetta mission (inc. lander).

BTW: Official press release on the arrival: http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_arrives_at_comet_destination

Edited by Sky_walker
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Sky_walker

Sky_walker

Posted
Posted (edited)

dn25995-2_850.jpg

And we have a first analysis of potential landing sites for Philae:

May the SCIENCE! commence!

There's 21 science instruments on Rosetta and Philae - sounds like a sh1tton of science points! :P

Edited by Sky_walker
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