Jump to content

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

Vicomt

By Vicomt
in Science & Spaceflight

 Share

Recommended Posts

Scotius

Scotius

Posted
Posted

This is so awesome :) Anyone remembers excitement from the last century when cavalcade of probes visited Halley comet? Photos sent by Vega and Giotto probes while amazing, can't hold the candle to pictures sent by Rosetta.

Link to comment
Share on other sites
Sky_walker

Sky_walker

Posted
Posted
Photos sent by Vega and Giotto probes while amazing

Oh yea, Giotto probe... glad someone still remembers that. One of the missions proving ESA got balls:

Giotto passed Halley successfully on 14 March 1986 at 596 km distance, and surprisingly survived despite being hit by some small particles. One impact sent it spinning off its stabilized spin axis so that its antenna no longer always pointed at the Earth, and importantly, its dust shield no longer protected its instruments. After 32 minutes Giotto re-stabilized itself and continued gathering science data.
Link to comment
Share on other sites
lajoswinkler

lajoswinkler

Posted
Posted
I have quite a bit of experience of selecting landing sites on extraterrestrial bodies (such as, you know, the Mun), and that flat area shows promise....

The roughness isn't very important. Gravity on the comet is extremely weak, so basically Philae can go wherever it wants. It won't roll down the hill. The problem is spinning of the comet. If you've ever landed on Gilly, you know how problematic those tall hills near the equator can be.

Luckily, this comet isn't tumbling so there shouldn't be any significant problems.

Link to comment
Share on other sites
Sky_walker

Sky_walker

Posted
Posted (edited)

Type of surface though is very important. Rough terrain might suggest rocks, and these could cause a serious trouble to the harpoon.

Besides - we'll see. I don't know exactly what Philae is capable of and what are the scientific objectives for it. Cause it's all really a calculation of risks vs scientific value.

Edited by Sky_walker
Link to comment
Share on other sites
Kryten

Kryten

Posted
Posted

There's also day-night cycles to take into consideration, especially as Philae is solar-powered; that's what the colour-coding is. Yellow=has cycle, red=permanent illumination, blue=permanent shadow.

Link to comment
Share on other sites
lajoswinkler

lajoswinkler

Posted
Posted
Type of surface though is very important. Rough terrain might suggest rocks, and these could cause a serious trouble to the harpoon.

Besides - we'll see. I don't know exactly what Philae is capable of and what are the scientific objectives for it. Cause it's all really a calculation of risks vs scientific value.

I meant to say that on the smallest scale of centimetres it matters, but it doesn't matter if it ends up in a field of bumps and slopes the size of a car. It won't flip and fall "on the floor". It basically won't land as much as it will dock to it.

Link to comment
Share on other sites
Sky_walker

Sky_walker

Posted
Posted (edited)
There's also day-night cycles to take into consideration, especially as Philae is solar-powered; that's what the colour-coding is. Yellow=has cycle, red=permanent illumination, blue=permanent shadow.

Night-day cycles are important not only because of solar panels, but also because of sublimation - you don't want to land somewhere just to be ejected by out-gassing ice near comet perihelion. And then there's also a matter of communication with the orbiter - Philae doesn't have an antenna capable of communicating with the Earth on it's own, so it needs to have a contact with Rosetta spacecraft.

In general - it's quite complex matter. ESA should select landing side in October.

I meant to say that on the smallest scale of centimetres it matters, but it doesn't matter if it ends up in a field of bumps and slopes the size of a car. It won't flip and fall "on the floor". It basically won't land as much as it will dock to it.

Well, that's why surveying surface is so important before the landing - so that your slope in a size of a car wouldn't come out to be a solid rock in a size of a car ;) But they already took that into account - that's why spacecraft will spend 2 months orbiting comet looking for a right spot to approach it and deliver Philae.

BTW:

harpoons.png

Edited by Sky_walker
Link to comment
Share on other sites
Kinglet

Kinglet

Posted
Posted
This is so awesome :) Anyone remembers excitement from the last century when cavalcade of probes visited Halley comet? Photos sent by Vega and Giotto probes while amazing, can't hold the candle to pictures sent by Rosetta.

Giotto probe!

ferrerogiottopackung154megadisplay.jpg

It's a shame that the media just does not care about Rosetta. I think the most this will get is a tiny mention in TV news and newspapers. It's been very long since we had a space headline in normal newspapers.

Link to comment
Share on other sites
4nxs

4nxs

Posted
Posted
Giotto probe!

It's a shame that the media just does not care about Rosetta. I think the most this will get is a tiny mention in TV news and newspapers. It's been very long since we had a space headline in normal newspapers.

We had live coverage of the rendezvous on the national 24/7 news channel so don't despair some media does care. Also it was nice to be able to watch something space related and not have it be in the middle of the night around 03:00.

I can't wait until KSP has some comets!

Link to comment
Share on other sites
Dkmdlb

Dkmdlb

Posted
Posted
It's a shame that the media just does not care about Rosetta. I think the most this will get is a tiny mention in TV news and newspapers. It's been very long since we had a space headline in normal newspapers.

I spent the weekend with extended family and mentioned it. Of the 23 people there, I was the only one who even knew about the mission. How is that even possible? It's such a cool mission!

Link to comment
Share on other sites
vger

vger

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

I didn't see any reason for them to NOT still cover it though, given how much of a big deal it is. It's all over their website, so why not?

Now I just need to find a time where I won't be interrupted. Livestream seems to reset automatically if I try to pause it.

Night-day cycles are important not only because of solar panels, but also because of sublimation - you don't want to land somewhere just to be ejected by out-gassing ice near comet perihelion.

Even accounting for that it could go awry. If they land on a chunk of rock that's only held to the rest of the comet by ice, it could still wind up taking an unexpected trip.

Edited by vger
Link to comment
Share on other sites
Streetwind

Streetwind

Posted
Posted
It's a shame that the media just does not care about Rosetta. I think the most this will get is a tiny mention in TV news and newspapers. It's been very long since we had a space headline in normal newspapers.

You might be happy to hear that my local newspaper, which is a fairly bog standard daily publication (no tabloid, but no scientific journal either) devoted its large, sole front page image to the stunning photo of the comet, and a full-page report on the inside with multiple contributing writers.

It may have to do with the fact that ESA's control center in Darmstadt is only 50 kilometers away, but still :P

Link to comment
Share on other sites
XIRA

XIRA

Posted
Posted
You might be happy to hear that my local newspaper, which is a fairly bog standard daily publication (no tabloid, but no scientific journal either) devoted its large, sole front page image to the stunning photo of the comet, and a full-page report on the inside with multiple contributing writers.

It may have to do with the fact that ESA's control center in Darmstadt is only 50 kilometers away, but still :P

I just got back from my vacation and was suprised that here in the netherlands it reached the frontpage on several newspages too! :D

Link to comment
Share on other sites
Squelch

Squelch

Posted
Posted

I'm intrigued by what looks like tracks on the plain in this image.

67_P_2.png

My first thought was they were formed by boulders or concentrations of ice that while outgassing, rolled around on the surface, and I still can't get that out of my head.

Link to comment
Share on other sites
vger

vger

Posted
Posted
I'm intrigued by what looks like tracks on the plain in this image.

My first thought was they were formed by boulders or concentrations of ice that while outgassing, rolled around on the surface, and I still can't get that out of my head.

That had my attention too, but thought maybe they were fissures in the ice created by rapid heating? I don't think the comet has enough gravity for anything to 'roll' on it, much less make an impression while doing it.

Link to comment
Share on other sites
Squelch

Squelch

Posted
Posted
That had my attention too, but thought maybe they were fissures in the ice created by rapid heating? I don't think the comet has enough gravity for anything to 'roll' on it, much less make an impression while doing it.

If the surface is as soft and powdery as they suspect, then even a very low gravity would keep a boulder in proximity and make an impression. I'm sure I can see points along those tracks that have a telltale fan shaped erosion pattern. That said, it may just be tricks of the light, and as new mapping comes in things will be clearer - if you'll excuse the pun?

Link to comment
Share on other sites
This thread is quite old. Please consider starting a new thread rather than reviving this one.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
 Share
Go to topic listing
×
×
  • Create New...