Giotto’s brief encounter, Twenty years ago Options

[tedstryk]

Does anyone know, if the image data of the 6 spacecraft observing Halley (the "Halley Armada") have been combined together, creating 3D models of the nucleus and the atmosphere, for example?

Second, would it be worth digging up the original Vega images?

Is there anything new we can learn from reprocessing the original images, or there's no relevant development in image processing since '85?

No need to dig...the PDS has them.

[Phil Stooke]

The Giotto images are very tricky to work with. They are little thumbnail-type images, they are not rectangular. You can't use them for shape modelling without knowing the pointing directions, and you can't know that without knowing the rotation state. It took years to sort that out. A rather dubious shape model is available in PDS. I say dubious because I made it. The fact that nobody has tried to do better than me since then only reinforces how poor the data are. We could really use a close flyby while the nucleus is relatively quiescent, like about now.

My shape is probably too faceted, based on comparisons with Peter Thomas's models of objects I have also done. (His are probably too smooth).

Phil

[spdf]

You mentioned the same idea with another spacecraft at some point - but it would be much MUCH easier just to mount a mission to go and collect samples from a comet (i.e. Stardust) than attempt to rendezvous with, encapsulate, and bring home an entire spacecraft. that was never designed to collect samples and is likely to show damage, but certainly not an aerogel like capture of samples.For all we know, leaking hydrazine might have put Giotto into a massive spin. It might have broken apart, or it might be in a steady state of spin still. It's a cute idea - bringing these things home - but ultimately pointless and certainly an enormous waste of a very limited budget.Doug

Are you sure? The only damaged parts were the camera I thought. And Giotto had another encounter with a comet in 1992 (with Grigg-Skjellerup). In 1999 it had its second Earth fly by. So the damage to the spacecraft might be rather limited? So definite not broken apart.

[djellison]

In 1999 it had its second Earth fly by. So the damage to the spacecraft might be rather limited? So definite not broken apart.

It was on a trajectory for that Earth flyby - but the spacecraft was turned off in July 1992. It has not been tracked for more than 15 years. There's no 'definite' about the status of Giotto. We have no idea what sort of state it's in.

Doug

[Stu]

The Giotto encounter... wow, there was a night... I remember watching it on TV, with Patrick Moore hosting a show on BBC2 which was going to show the images coming in from Giotto live as they were received. My family wanted to watch something on another channel, and we had no VCR at the time, so I was left to keep flicking channels whenever I got the chance until the ITV program finished then I was able to watch the Giotto broadcast.... lots of tense build-up to the appearance of the close approach pictures... The approach pics were good, showing the shape of the nucleus, but we all wanted to see the closest images...

Then they appeared, and showed - well, no-one knew what the hell they showed to be honest! They looked a bit psychedelic to me, a colourful mishmash of no-idea-what... cue lots of puzzled looks from my family as they asked me what they were seeing and I had to admit I really had no idea!

[rasun]

No need to dig...the PDS has them.

Oops, I didn't notice them before; thanks.

Phil: and how did you do the modeling? Was the atmosphere annoying? Did you just forget the parts of the images that clearly a showed gas/dust cloud/jet, and creating the model based on the rest (the quieter parts)? Or how is this sort of job exactly done?

And were the Vega 2 images not detailed enough to be of additional use?

Sorry for too many questions.

[AndyG]

I remember watching it on TV...

Was that not the close encounter where James Burke confused the ESA clock times? He wasn't sure whether the "minutes before encounter" time took into account light lag - and therefore the viewers got confused too?

Andy

[Guest_PhilCo126_*]

Just read that photos were taken as close as 1300 Km (data taken closer was later recovered) and Giotto passed as close as 606 Km of the nucleus... Just wonder how many photos were taken by Giotto (some sources say 2112 while others list image n° 3475)

[Paolo]

In Robotic Exploration vol 2 we have 1703 km and 596 km. we do not have the total number of images but we mention 2043 pictures taken in single CCD mode, which lasted from 20.55 to 23.58 UTC. For the last five minutes of the encounter Giotto used a 4-sensor mode.

[machi]

I have a question. Can I put here some improved Halley comet images, or do I have to write to dr. H. U. Keller first? There in an information on PDS data set, that the data are copyrighted and the owner of copyright is dr. H. U. Keller. Data are free of charge for scientific purposes. But if I post them here, are they scientific purposes?

[djellison]

Post them, by all means. It's European data paid for by European tax payers (of which I am one). If anyone moans - they can come and talk to me about it (and I shall bash them over the head, repeatedly, with my new iPhone 3GS )

[Floyd]

Doug or other Admin may give the definitive answer, but I think posting a link to anything on the web is always OK. Then it is up to those who follow the link to download appropriately.
Edit: Doug is too fast

[ngunn]

I'm keen to see them! Whether what I do with them afterwards is appropriate or not I'll leave to George Orwell. (Nice one Doug - I think you enjoyed posting that. )

[machi]

Allright. Here is animation from flyby images before camera failure.

Attached image(s)

 

[Paolo]

Allright. Here is animation from flyby images before camera failure.

Coooool!!
If you could only slow it down a little bit