"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 about 10 kilometers (6.3 miles) per second," said a statement from NASA's Jet Propulsion Laboratory (JPL) at Pasadena, near Los Angeles.

"The major surprise was the opacity of the plume the impactor created and the light it gave off," said Deep Impact chief investigator Michael A'Hearn, of the University of Maryland.

"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 comet measuring five-kilometers-wide by 11-kilometers-long (three by seven miles)."

The information also includes some 4,500 images taken when the impact occurred, NASA said.

The washing machine-sized projectile crashed head-on into the Tempel 1 comet at 0552 GMT Monday, with the collision photographed by a separate fly-by spacecraft.

Within minutes of the crash, scientists were able to pore over a wealth of high-resolution images showing a bright flash of light as the projectile collided with the potato-shaped comet that was discovered in 1867.

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