Mike's probably right. The orbiter/lander package is going to be pacing the comet in order for the lander to plunk down nice and slow so there shouldn't be much in the way of charge differential. Like Mike said, the Deep Impact mission was designed to hit hard and make a relatively big hole. Rosetta's a ESA mission, btw.
Unlike the copper projectile of Deep Impact,
The (Philae) lander structure consists of a baseplate, an instrument platform, and a polygonal sandwich construction, all made of carbon fibre. Some of the instruments and subsystems are beneath a hood that is covered with solar cells.
An antenna transmits data from the surface to Earth via the orbiter. The lander carries nine experiments, with a total mass of about 21 kilograms. It also carries a drilling system to take samples of subsurface material.
I think they're landing before the comet gets real active. The lander is mostly non-conductive carbon fibre so the electronics should be OK...at least until the comet begins to discharge, increasing the vulnerability of electrical systems. I wouldn't expect any discharge activity when the harpoon anchor hits the surface either.
My concern is that, after activity picks up, if we're fortunate enough for a local discharge to occur around the landing zone, the instruments might get fried preventing us from getting any data on the event. Regardless, I wouldn't be surprised if they have ongoing issues with the electronics and/or communications between lander and orbiter as the comet gets closer to the sun.
"Is the whole image of Ben Franklin and the kite a myth? Did he do lightning research?
He showed that there was electricity in thunderstorms. He flew the kite and sparks came off the bottom. He didn't want the kite to be struck by lightning. In fact, if you put something up slowly into the atmosphere, it generally doesn't trigger lightning. You have to get it up there in a hurry. "
(I didn't much care for their conclusions of how lightning was caused by the Apollo 12 transition through the atmosphere though)
mharratsc
Re: ESA Rosetta Stone 2014
Well, they're almost right. Craft cooking through the atmosphere create a plasma trail much akin to those rockets trailing a wire behind them trying to induce lightning.
Once those craft travel between distinct double-layers of charge within our atmosphere- BAM. One of the U.S.'s shuttles was taken out like that, on re-entry if you'll recall.
fosborn
Re: ESA Rosetta Stone 2014
Once those craft travel between distinct double-layers of charge within our atmosphere- BAM. One of the U.S.'s shuttles was taken out like that, on re-entry if you'll recall.
A terrible lesson. And ironic all the more, if they refuse to understand it.
Nereid
Re: ESA Rosetta Stone 2014
Does anyone know if Wal Thornhill (or anyone else) intends to publish EU predictions, as he did for Deep Impact, of what data Rosetta's instruments will return, once it reaches and begins to study Comet 67 P/Churyumov- Gerasimenko?
David Talbott
Re: ESA Rosetta Stone 2014
Nereid wrote: Does anyone know if Wal Thornhill (or anyone else) intends to publish EU predictions, as he did for Deep Impact, of what data Rosetta's instruments will return, once it reaches and begins to study Comet 67 P/Churyumov- Gerasimenko?
I'm sure he will in due course. And personally I'd like to see lots of advanced analyses from both the mainstream and the EU perspectives, in order to highlight the contrasts. All involved in such an exchange should honestly acknowledge that Wal's key predictions were remarkably accurate. Considering that his predictions challenged mainstream expectations, that fact alone should encourage a thoughtful exchange.
Nereid
Re: ESA Rosetta Stone 2014
David Talbott wrote:
Nereid wrote: Does anyone know if Wal Thornhill (or anyone else) intends to publish EU predictions, as he did for Deep Impact, of what data Rosetta's instruments will return, once it reaches and begins to study Comet 67 P/Churyumov- Gerasimenko?
I'm sure he will in due course. And personally I'd like to see lots of advanced analyses from both the mainstream and the EU perspectives, in order to highlight the contrasts.
Thanks.
Did he (or anyone else) publish predictions for EPOXI's encounter with Hartley 2 (I did a search for any, but it came up blank; maybe I was looking in the wrong place, or using the wrong terms)?
mharratsc
Re: ESA Rosetta Stone 2014
Hey Nereid- would you happen to know of a good site where we can look at some summarized 'mainstream' predictions for these missions also, so we can do some comparisons? That would be cool to see
fosborn
Re: ESA Rosetta Stone 2014
<<Nereid : Did he (or anyone else) publish predictions for EPOXI's encounter with Hartley 2 (I did a search for any, but it came up blank; maybe I was looking in the wrong place, or using the wrong terms)?>>
mharratsc wrote: Hey Nereid- would you happen to know of a good site where we can look at some summarized 'mainstream' predictions for these missions also, so we can do some comparisons? That would be cool to see
+ 1
Nereid
Re: ESA Rosetta Stone 2014
mharratsc wrote: Hey Nereid- would you happen to know of a good site where we can look at some summarized 'mainstream' predictions for these missions also, so we can do some comparisons? That would be cool to see
I don't know of any such site ... but then I don't follow this subject very closely.
Most likely you'll find what you're interested in in conference presentations, workshop proceedings, and the like; however, they are likely to be quite technical.
genogeno1
Shoemaker Levy 9 Comet Flash Prior to Impact
I was reviewing the photos from the Shoemaker Levy 9 comet impact with Jupiter back on July 16, 1994 and came across this peculiar time sequence photo from impact A (the first comet fragment impact). It appears to show the first comet fragment just prior to entering the atmosphere at between 1000 and 1500 km above the surface. What is funny is that the Hubble website, in their canned answer to this enigma states something to the effect that it might be due to shadows or reflections off the atmosphere. That is all they say about it. I can go back and find the actual link if necessary, I just wanted to make sure I wasn't reinventing the wheel. It looks to me like a flash or discharge of some sort well outside the atmosphere of Jupiter very similar to the one observed on the latest comet mission and predicted by Walt Thornhill. Has anyone else noticed this?
tayga
Re: Shoemaker Levy 9 Comet Flash Prior to Impact
Wal's prediction for Deep Impact included the flash:
Tempel 1 has a low-eccentricity orbit. Therefore its charge imbalance with respect to its environment at perihelion is low. (It is a 'low-voltage' comet.) Electrical interactions with Deep Impact may be slight, but they should be measurable if NASA will look for them. They would likely be similar to those of Comet Shoemaker-Levy 9 prior to striking Jupiter's atmosphere: The most obvious would be a flash (lightning-like discharge) shortly before impact.
