Bullseye for Deep Impact

After 172 days and 268 million miles of deep space stalking, Deep Impact successfully reached out and touched comet Tempel 1.

The collision between the coffee table-sized impactor and city-sized comet occurred at 1:52 am EDT.

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

"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."

Official word of the impact came 5 minutes after impact when, at 1:57 am EDT, an image from the spacecraft's medium resolution camera was downlinked to the computer screens of the mission's science team showed the tell-tale signs of a high-speed impact.

"The image clearly shows a spectacular impact," said Deep Impact principal investigator Dr. Michael A'Hearn of the University of Maryland, College Park. "With this much data we have a long night ahead of us, but that is what we were hoping for. There is so much here it is difficult to know where to begin."

The celestial collision and ensuing data collection by the nearby Deep Impact mothership was the climax of a very active 24 hour period for the mission which began with impactor release at 2:07 am EDT on July 3. Deep space maneuvers by the flyby, final checkout of both spacecraft and comet imaging took up most of the next 22 hours. Then, the impactor
got down to its last two hours of life.

"The impactor kicked into its autonomous navigation mode right on time," said Deep Impact navigator Shyam Bhaskaran, of JPL. "Our preliminary analysis indicates the three impactor targeting maneuvers occurred on time at 90, 35 and 12.5 minutes before impact."

At the moment the impactor was vaporizing itself in its 6.3 miles a second collision with comet Tempel 1, the Deep Impact flyby spacecraft was monitoring events from nearby and will continue to do so for the next several days.

"The flyby surviving closest approach and shield mode has put the cap on an outstanding day," said Grammier. "Soon, we will begin the process of downlinking all the encounter information in one batch and hand it to the science team."

Deep Impact will 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.

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.

Source: NASA/JPL