NASA Hits Comet: Deep Impact Experiment a Success

PASADENA, California, July 4, 2005 (ENS) - Eighty-three million miles from Earth between the planets Jupiter and Mars, the Comet Tempel 1 was intentionally struck early this morning by a chunk of copper the size of a coffee table, sent into space by NASA scientists.

The collision between the 820 pound impactor and city-sized comet occurred at 1:52 am EDT when the impacter crashed at a speed of about 10 kilometers per second (6.3 miles per second or 23,000 miles per hour).

Official word of the impact came five minutes later when an image from the spacecraft's camera downlinked to the computer screens of the mission's science team showed the high-speed impact.


This image shows the view from Deep Impact's flyby spacecraft as it turned back to look at comet Tempel 1. Fifty minutes earlier, the spacecraft's probe was run over by the comet. That collision kicked up plumes of ejected material, seen here streaming away from the back side of the comet. (Photo courtesy NASA/JPL-Caltech/UMD)
"This mission is truly a smashing success," said Andy Dantzler, director of NASA's Solar System Division. "Tomorrow and in the days ahead we will know a lot more about the origins of our solar system."

NASA launched the two part Deep Impact spacecraft from Cape Canaveral on January 12, 2005. The goal of the Deep Impact mission is to provide a glimpse beneath the surface of a comet, where material from the solar system's formation remains relatively unchanged.

Mission scientists expect the project will answer basic questions about the formation of the solar system, by offering a better look at the nature and composition of the frozen celestial travelers known as comets.

"What a way to kick off America's Independence Day," said Deep Impact Project Manager Rick Grammier of NASA's Jet Propulsion Laboratory in Pasadena. "The challenges of this mission and teamwork that went into making it a success, should make all of us very proud."

The cometís nucleus is about two miles wide. The collision of the 39 inch wide impactor will not be forceful enough to change the comet's orbital path around the Sun. Nor will the impact affect the planet Earth, other than adding to human understanding of the nature of the universe.

At the world's largest telescopes, the W.M. Keck Observatory on the summit of Mauna Kea on Hawaii's Big Island, astronomers trained the two 10 meter mirrors on the strike zone.

"All the major telescopes on Mauna Kea are working together to be certain that we use the best capabilities of each facility, said Keck Director Fred Chafee. "The data we obtain will be made publicly available as soon after the event as possible so that astronomers all over the world can begin to digest and interpret the results."

Chafee says for the first time humans can see what lies beneath the surface of a comet.

The Keck Observatory will help test theories of solar system formation by studying the first cosmic collision visible from Earth since comet Shoemaker-Levy 9 smashed into Jupiter in 1994. The observations will also help investigate whether Earthís water may have originated from comets.

Comets are time capsules that hold clues about the formation and evolution of the solar system, NASA scientists say. They are composed of ice, gas and dust, which is the primitive debris from the solar system's earliest and coldest formation period, about 4.5 billion years ago.


Deep Impact team celebrates after the first impact photo is returned to Earth from 83 million miles in space. (Photo courtesy NASA/JPL)
Comet Tempel 1 was discovered in 1867 by German astronomer Ernst Tempel. The comet has made many passages through the inner solar system, orbiting the Sun every 5.5 years. This makes Tempel 1 a good target to study evolutionary change in the mantle, or upper crust, NASA said.

The smash of NASA's Deep Impact probe generated an immense flash of light, which provided an excellent light source for the two cameras on the Deep Impact flyby unit.

Preliminary assessment of the images and data downlinked from the flyby spacecraft have provided a glimpse into the life of a comet.

"They say a picture can speak a thousand words," said Grammier. "But when you take a look at some of the ones we captured in the early morning hours of July 4, 2005 I think you can write a whole encyclopedia."

At a news conference today, Deep Impact team members showed a movie depicting the final moments of the impactor's life. The final image from the impactor was transmitted three seconds before it met its fiery end.

"The final image was taken from a distance of about 30 kilometers (18.6 miles) from the comet's surface," said Deep Impact Principal Investigator Dr. Michael A'Hearn of the University of Maryland, College Park.

"You can not help but get a big flash when objects meet at 23,000 miles per hour," said co-investigator Dr. Pete Schultz of Brown University. "The heat produced by impact was at least several thousand degrees Kelvin and at that extreme temperature just about any material begins to glow. Essentially, we generated our own incandescent photo flash for less than a second."

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