# Talk:Deep Impact (spacecraft)

Just curious, was the mission named after the movie Deep Impact? I haven't checked the history of the edits on this page, or the movie page, but I figured you guys might be able to tell me with less effort.
Karmafist 4 July 2005 21:27 (UTC)

It says right in the article. Deep_Impact_(space_mission)#Before_launch - Omegatron July 5, 2005 01:52 (UTC)
No, oh look, why not look at the actual mission website! http://deepimpact.umd.edu/mission/di-name.shtml

The probe definetly hit the comet, with a pretty massive plume to boot.  By my watch it was at about 1:00am CDT. --LouieS 4 July 2005 06:03 (UTC)

- Did the NASA make sure that the comet has no life whatsoever, including primitive single-cell organisms (genocide)
- Did the NASA make sure no other civilization has installations on the comet or claim it as their own, e.g. comet is hollow and is the birth planet of little green men with 3 eyes (attack without declaration of war)
- What happens if sheds from the explosion damage some places on the Earth or destroy some other spacecraft (insurance)
The world is really fed up with US aggression. Vietnam, Granada, Panama, Iraq and now Comet Tempel. This comet bombing is the wettest dreams of evil "Star Wars" Teller and Ronnie Raygun come true.

hehehe :-) Dave (talk) July 1, 2005 13:08 (UTC)
PS If you're worried about that sort of thing, see the "controversy" section on the article page.

Well, comets are coated in a tar of fairly complex aminoacids.  But um, no, theres no life on it; if there were life on this or any other comet in out solar system, I would start believeing in god because thats the only way it could happen.  Hey, at least it's better than the antimatter fantasy. -LouieS 4 July 2005 05:15 (UTC)

I've changed all the time in Ground UTC to Orbiter UTC. So the impact time should be 05:44:34 in SCET (One-Way Light Time = 7 minutes 26 seconds). -- Yaohua2000 3 July 2005 08:40 (UTC)

Thanks for clearing that up Yaohua2000. JamesHoadley 3 July 2005 09:30 (UTC)

I think calling this a constroversy pays to much tribute to the lonely crackhead that came up with that idea. Similar for any suggestions that the orbit might change dramatically or that the comet would break up.

That's a standard for Wikipedia's NPoV, if there's some wacko view, they deserve to be put in the article, so it goes under the heading Controversy. We could also drown them out. There's also
The Electric Universe theory reported in SlashDot, home page http://thunderbolts.info/tpod/2005/arch05/00current.htm
The Exploded Planet Hypothesis (EPH) reported in Usenet, home page http://metaresearch.org/solar%20system/eph/DeepImpact.asp
As a footnote, Controversy sections usually work well in subjects like politics, but in science they're usually cranks. Oh well.
JamesHoadley 4 July 2005 10:31 (UTC)
I'm the author of the antimatter bit of the article.  It can be removed if the consensus is against it, though I'd prefer to leave it in.  I think that: a) since we're lumping the antimatter theorists with "astrologers," it was pretty clear that we aren't taking their theory very seriously, and b) since NASA felt the need to respond to it, it was more than "one lonely crackhead."  I figured since Wikipedia isn't paper and it's just a little bit at the end of the article, there was no harm in putting in a discredited theory. Dave (talk) July 4, 2005 14:50 (UTC)
This was my comment originally. I am not a regular writer for wikipedia, so I don't know what the general policy is. I think  that in a political topic there is usually some ethnic group that has a different view, as in 5 percent of a population. This is science however, and it is one crackhead against the rest of the world, so it is hardly a NPOV issue. If you would allow this you could add a controversy section to every scientific theory that is otherwise undisputed. I think that in most cases (barring hot topics like evolution) it does not justify the clutter/distraction of an extra paragraph. I am strongly in favor of removal. Cheers, Bas
This view is obviously held by a negligible minority and furthermore is entirely absurd. It is not notable and should be removed. It is NOT policy that any wacko view gets representation in an article and in my opinion that kind of attitude is just a concession and an invitation to the trolls. If this antimatter thing were widespread and covered in the media or whatever, we could note it but at the moment its just wasting article space. The astrologer thing could go under the same category of being irrelevant and unimportant, but maybe that's a bit more notable. --Tothebarricades July 5, 2005 03:40 (UTC)
I wouldn't call it even a minority. Calling it "controversy" makes it appear more important than it really is. I really recommend removing that part, or at least renaming the title, although it is funny in a sad way.--Jyril July 5, 2005 08:01 (UTC)
All right.  I know consensus when I see it.  I'll remove it. Dave (talk) July 5, 2005 12:43 (UTC)

Do someone know the exact mass of the Deep Impact flyby spacecraft? Because NASA says on some of its pages ([1]) that it weights 650kg, and in its press kits (Launch Press Kit and Encounter Press Kit, PDFs!) 601 kg. --Bricktop 4 July 2005 17:59 (UTC)

I wonder why photos from the impact showed a bright luminous explosion. There was no detonation or explosion that could have caused this. Or is this another feed for conspiracy theory, igniting a nuclear bomb on Temple 1 in a desperate struggle to move that comet away from its unescapable impact track to earth? (See, that's why they gave Deep impact the same name as the movie Deep Impact, so only insiders know what really is going on. --Abdull 5 July 2005 22:35 (UTC)

All you need for an explosion is a "hot" material that wants to expand. Yes, here on Earth you do this with explosive materials for convenience, but there on the comet, a fast, ca 600 kg heavy block of stuff being decelerated to relative zero speed will create the same thing. Remember: Pressure = Heat. There as a lot of pressure on that copper block during decelaration!! Another way to put it is that all the kinetic energy was converted to heat, and so "boom" :-) Awolf002 6 July 2005 00:21 (UTC)
You really don't want to use any kind of explosive here. Kinetic energy is sufficient. Moreover, they don't want to stuff too much organic materials on the impactor because it will surely pollute the spectrum readings with foreign CO2, H2O, NOx ... molecules. Copper is exotic to the comets so it's easier to disregard copper. I wonder if we could use depleted uranium or else ... -- Toytoy July 6, 2005 00:29 (UTC)
Hi Awolf002, it's hard for me to think about pressure and heat when talking about near-vacuum space.  Do you have more information about this process (website etc.)? Thank you, --Abdull 6 July 2005 12:41 (UTC)
Check out these pictures at NASA. It shows the Ames vertical gun range experiment and pictures of simulated impacts. Also... When you hit the surface of a rocky object (like a comet) then you are obviously not talking about "near-vacuum," anymore. Awolf002 6 July 2005 13:27 (UTC)
A relatively small mass pulverised into tiny particles will reflect a lot of sunlight. The same principle works for Saturn's huge ring system (~100,000 km in size), which is estimated to have the same mass as a large comet or small moon (say something 50 km across). I don't think they really knew for sure that it would make a bright explosion, but it's no surprise. JamesHoadley 6 July 2005 16:03 (UTC)

http://www.newscientistspace.com/article.ns?id=dn8670
The goal "Are cometary nuclei highly cohesive and tightly-packed, or porous conglomerates?" has been proven; should someone add something in there? I would recomment a strikethrough, and a link to this article.
David Souther

The article states:
 Impact occurred at 05:45 UTC (05:52 UTC ERT, +/- up to three minutes, one-way light time = 7m 26s) on the morning of July 4, 2005, within one second of the expected time for impact.
I find this pretty confusing.  It seems to imply that there is 3 minutes uncertainty in the impact time;  but then it implies the impact time is known within one second.  That seems to be a contradiction.  
Could someone please update the article to clarify the inconsistency?  (PS:  I'm not asking for clarification for my own benefit here in the talk page:  I'm asking for an update to the article so all future readers beneift). Thanks!


### Deep Impact (spacecraft)