Deep Impact tells a tale of the powder-coated comet

NASA via Spaceflight Now ^ | 7/8/2005 | NASA NEWS RELEASE

[Excuse_My_Bellicosity]

Data from Deep Impact's instruments indicate an immense cloud of fine powdery material was released when the probe slammed into the nucleus of comet Tempel 1 at 6.3 miles per second.

The cloud indicated the comet is covered in the powdery stuff. The Deep Impact science team continues to wade through gigabytes of data collected during the July 4 encounter with the 3-mile-wide by 7-mile-long comet.

"The major surprise was the opacity of the plume the impactor created and the light it gave off," said Deep Impact Principal Investigator Dr. Michael A'Hearn of the University of Maryland, College Park. "That suggests the dust excavated from the comet's surface was extremely fine, more like talcum powder than beach sand. And the surface is definitely not what most people think of when they think of comets -- an ice cube."

How can a comet hurtling through our solar system be made of a substance with less strength than snow or even talcum powder?

"You have to think of it in the context of its environment," said Pete Schultz, Deep Impact scientist from Brown University, Providence, R.I. "This city-sized object is floating around in a vacuum. The only time it gets bothered is when the sun cooks it a little or someone slams an 820-pound wakeup call at it at 23,000 miles per hour."

The data review process is not overlooking a single frame of approximately 4,500 images from the spacecraft's three imaging cameras taken during the encounter.

"We are looking at everything from the last moments of the impactor to the final look-back images taken hours later, and everything in between," added A'Hearn. "Watching the last moments of the impactor's life is remarkable. We can pick up such fine surface detail that objects that are only four meters in diameter can be made out. That is nearly a factor of 10 better than any previous comet mission."

The final moments of the impactor's life are important, because they set the stage for all subsequent scientific findings. Knowing the location and angle the impactor slammed into the comet's surface is the best place to start. Engineers have established the impactor took two not unexpected coma particle hits prior to impact. The impacts slewed the spacecraft's camera for a few moments before the attitude control system could get it back on track.

The penetrator hit at an approximately 25 degree oblique angle relative to the comet's surface. That's when the fireworks began.

The fireball of vaporized impactor and comet material shot skyward. It expanded rapidly above the impact site at approximately 3.1 miles per second, and the crater was just beginning to form.

Scientists are still analyzing the data to determine the exact size of the crater. Scientists say the crater was at the large end of original expectations, which was from 50 to 250 meters.

Expectations for Deep Impact's flyby spacecraft were exceeded during its close brush with the comet. The craft is more than 2.2 million miles from Tempel 1 and opening the distance at approximately 23,000 mph. The flyby spacecraft is undergoing a thorough checkout, and all systems appear to be in excellent operating condition.

The Deep Impact mission was implemented to provide a glimpse beneath the surface of a comet, where material from the solar system's formation remains relatively unchanged. Mission scientists hoped the project would answer basic questions about the formation of the solar system by providing an in-depth picture of the nature and composition of comets.

The University of Maryland is responsible for overall Deep Impact mission science, and project management is handled by JPL. The spacecraft was built for NASA by Ball Aerospace & Technologies Corporation, Boulder, Colo.

[Excuse_My_Bellicosity]

This false-color image shows comet Tempel 1 about 50 minutes after Deep Impact's probe smashed into its surface. The impact site is located on the far side of the comet in this view. The image was taken by the mission's flyby spacecraft as it turned back to face the comet for one last photo opportunity. The colors represent brightness, with white indicating the brightest materials and black showing the faintest materials. This brightness is a measure of reflected sunlight. The Sun is located to the right, out of the picture. Credit: NASA/JPL-Caltech/UMD

[demlosers]

Does this mean we can ski on comet?

[Excuse_My_Bellicosity]

Sure, but the lift ticket is kinda expensive.

[Maceman]

Does this mean we can ski on comet?

I'm thinking the lift tickets might be a bit pricey. But if ya got it, flaunt it baby!

[Vinnie]

The thing that surprised me was the craters on the surface. More akin to an asteroid.
Having learned comets were primarily balls of ice and seeing the comet appears to be a very solid object has me questioning what is being thrown off, causing the 'tail'.

[bitt]

bttt

[CROSSHIGHWAYMAN]

Powder you say?

Sounds like Bill Kristol might be interested in adding to his puff collection.

[Mamzelle]

re:an improvement by a factor of 10; 25 degree oblique angle relative to the comet's surface.)))

Hey, that's about the angle you use to hone and sharpen a kitchen knife...

[devane617]

OK, so it is a dirty comet. Now what?

[bert]

It was STARDUST

And now the purple dusk of twilight time
Steals across the meadows of my heart
High up in the sky the little stars climb
Always reminding me that we’re apart
You wander down the lane and far away
Leaving me a song that will not die
Love is now the stardust
Of yesterday
The music
Of the years
Gone by



Sometimes I wonder why I spend
The lonely nights
Dreaming of a song.
The melody haunts my reverie
And I am once again with you.
When our love was new, and each kiss an inspiration.
But that was long ago, and now my consolation
Is in the stardust of a song.
Beside the garden wall, when stars are bright
You are in my arms
The nightingale tells his fairy tale
Of paradise where roses grew.
Though I dream in vain, in my heart you will remain
My stardust melody
The memory of love’s refrain.

[ml/nj]

Having learned comets were primarily balls of ice and seeing the comet appears to be a very solid object has me questioning what is being thrown off, causing the 'tail'.

Glad to see someone else here thinks like me. (Does ice crater when impacted?)

And now "powder"? What could posssibly have brought this powder to the surface and keep it in place? The escape velocity from such a small mass must be next to nothing.

ML/NJ

[RandallFlagg]

The powder is used to coat the fuel rods for the ISD's power plants. And the residual is filtered, melted and used for oxygen production.

That's what I hear, anyway....

[TheGeezer]

Whacking comets causes hurricanes...

[Vinnie]

I've always questioned the ice theory.
Ice sublimes in a vacuum. How can there be ice on a comet, or the Moon for that matter?
Certainly over the millions of years these objects are supposed to have existed any ice would have long ago evaporated. IMHO anyway.( that is how they make freeze dried food)

[cloud8]

So now that the Flyby Craft has flown by and accomplished its mission, what will become of it? Will it keep flying on? Will we hear from it again?

[DustyMoment]

Well, I guess I will be the one out-of-step on this thread. Spending a third of a billion dollars to penetrate a comet is pseudo-science at its worst and a huge waste of government (our) money.

NASA didn't do anything spectacular by crashing an object into a comet, they're well-versed in crashing space vehicles.

Frankly, I'm just not impressed by this so-called great "achievement".

[archaicoldschool]

Gee, maybe the technology could be adapted to strike an incoming missle...

[USFRIENDINVICTORIA]

"Gee, maybe the technology could be adapted to strike an incoming missile..."

One of the stupidest objections raised to the proposed missile shield is the notion that it won't work.

[RightWhale]

Before the moon landings it was thought that the moon could be covered with a fine powder to a considerable depth, and that a lander could sink out of sight.