Cometary Fireworks Go Off Without Hitch

PingXao writes "The JPL Deep Impact mission has successfully slammed a sattelite into Tempel 1 at 23,000 mph. (37,000 kph). The autonomous navigation system was primed for up to 3 course corrections in the final 2 hours of flight but only had to execute two of them. The second was so small - expending less than a pound of propellant - that impact would have occurred without it. Initially thought to be shaped like a pickle, it came to resemble more of a banana shape as comet Tempel I drew closer. Impact was estimated to have released 19 Gigajoules of energy, or the equivalent of 4.5 tons of TNT."

Comments

Seems a Lot Smoother Than I Would Have Thought

[DanielMarkham]

With all that outgassing, you would think a comet's surface would be a lot more sharp -- full of crevasses and ridges (like it was on Deep Impact) But this one seemed almost smooth, like an asteroid. I wonder if this will change the theory of how comets are constructed?

Ugliest Dog I Ever Saw

Re: Result

[Black Parrot]

> This is quite likely the finest result Nasa has had for a long time.

Ignoring a couple of rovers on Mars...

Star wars (Regan version)

[Anonymous Coward]

The kind of accuracy necessary to hit a speeding comet blows my mind. Sadly, that's the kind of accuracy necessary to shoot down an ICBM.

This has to give the Star Wars proponents some hope and ammunition. Darn. Mind you, it looks like its going to happen anyway.

Re:A mini-animation

[Dunbal]

If the probe is travelling at 37,000 kph that's what, about 10.3 km/sec. Whoa, that comet is absolutely huge and the camera has an incredible number of frames/second. I guess if you know the radius of the comet and the speed of the probe you could calculate time it took for the whole series and thus the FPS on the camera...since I don't think the "movie" is in "realtime" (there are far too many "close up" shots compared to "far away" shots, as if the probe had slowed down or the camera was speeded up). It also looks as if the camera was "zoomed" right at the end - the strip of data (top scanline, right side) gets bigger and bigger. What did they expect to see? Ants?

I leave it as an excercise for the geek physicist reader - I'm a biologist (too much math for me ugh!).

Re:Where are the Stars in the pictures?

[tomhudson]

Don't be so uptight about your typo. It's not like there aren't any in the article summary itself:

PingXao writes "The JPL Deep Impact mission has successfully slammed a sattelite into Tempel 1

Is it too much to expect the editors to, um, *edit* the stories?

a question of priorities in the united states.

[Anonymous Coward]

Is this what my tax dollars are going to? games the folks at nasa can play? crashing expensive spacecraft into comets? making fireworks?

come on where are our priorities?
genocide? starvation? ecological collapse?
NO

Funding NASA so they can make fireworks in space and have a ball crashing spaceships into comets. this makes me sick.

Re:a question of priorities in the united states.

[Dunbal]

come on where are our priorities?

The cost of this mission to you does not represent tax dollars to you. In fact, it's probably tax "cents". Tell me how a few million dollars will end starvation, genocide or ecological collapse? It would just be wasted there, too. At least this way we "waste" it in new and unusual ways and gain knowledge, but I know this is not important to you.

Re:A mini-animation

[joeljkp]

It says in the caption that the movie is just a slideshow of stills. I'm guessing they included more close-up ones because it would be more interesting (and shorter) that way.

Re:Partly Offtopic

[Anonymous Coward]

I'm surprised; I expected "US unilaterally invades comet".

Re: Result

[Bhalash]

And a lil ol' probe named Cassini

Re:Where are the Stars in the pictures?

[TheKidWho]

how is it not orbiting the sun?

Im a phycisist here btw, so please do enlighten me.

Re:And now in terms you're familiar with

[Weaselmancer]

Ok that's about the best laugh I've had on Slashdot in a *long* time. =)

We Come in Peace - Shoot To Kill

[Doc Ruby]

It's like stabbing a screwdriver into a Swiss watch, to learn how it keeps time.

Next Time

[jmichaelg]

It was a very impressive achievement. We need to do a lot more of these missions so we have an adequate sample of what comets look like because, scoff if you will, eventually earth will be endangered by one. If we have a sample of several comets we can make reasonable plans as to how to deflect them. Right now we have a sample of one.

Next time would be better if:

• There's enough fuel on the mother ship to drop the impactor and then get out of harm's way to turn around to match speeds with the comet. The mother ship can linger over the crater for years watching the newly formed crater evolve.
• The mother could land another drop ship in the newly excavated crater to give us a closeup of the comet's interior.
• Deploy several microprobes that have little seismometers on them. As the comet outgasses, the seimic waves will give us information as to how the comet's interior is structured. Each seismometer could be powered with a small atomic battery which would enable it to operate for years and provide ample power to broadcast the seismometer's readings to the mother ship.
• Make sure the equipment functions properly before it's launched. Blurry hi res photos because someone forgot to calibrate the equipment or parachutes that fail to open over Utah because they're installed backwards aren't ok.

standard operating procedure

[khallow]

I don't know the details but traditionally the scientists working on an astronomy project whether it be Hubble, Keck, or the VLA have first crack at the data. And the low quality of the pictures may be due to bandwidth. It appears there are two cameras, the "medium resolution" one and a "high resolution" one. Both have built in spectrometers. For pictures in which you can see most or all of the comet at the time of impact, that is from the medium res camera.

The first remark is that they haven't transfered most of the data back yet. So pictures from the lower res camera probably came first. You may be seeing the best available.

Second, it is contradictory to both ask for the "raw" data, and then expect that data to be processed. Automated processing isn't useful scientifically. I doubt they have software smart enough to automatically compensate for the vagaries of the instrument and the data observed.

Re:A mini-animation

[radtea]

I leave it as an excercise for the geek physicist reader - I'm a biologist (too much math for me ugh!).

Ugh is right--a person pretending to be a scientist who can't do math.

Really, please, do the world a favour and get out of the sciences entirely if you aren't willing or able to learn the basic tools of the trade.

Biology is currently in a serious mess because of the huge amount of genomics and proteomics data being generated by people who don't have the mathematical ability to analyze it, or the scientific capability of understanding the instruments that generate it. I have worked extensively in this area (I'm a physicist) and it didn't take long to realize that biologists are by-and-large people who think they like science but who can't handle math.

For some reason no other science has this problem--geology, astronomy, oceanography, climatology, chemistry... all these people have over the past century come to terms with the fact that their field of study demands a mathematical language to describe it, and developed mathematical toolkits as part of the basic training in the field. Only the biologists, who need it the most, are still holding out.

Preliminary animation from Planetary Society

[FleaPlus]

The Planetary Society's Emily Lakdawalla put together a fairly nice animated GIF of the impact and posted it to the Society's official blog:

http://planetary.org.nyud.net:8090/deepimpact/imag es/encounter/animation-small.gif

Her description: OK, I've managed to get back on the raw image website, and I grabbed a whole bunch of the images that we were apparently looking at earlier. I just threw together this little animation, showing mostly Impact Targeting Sensor images, but moving at the end to some Medium Resolution Imager images. Now, I've probably dropped some frames, and these images are smaller than the ones the scientists get to use, but I have to say that this is pretty sweet as it is. I can't wait to see what the scientists produce!