[meteorite-list] NASA's Deep Impact Spacecraft Spots Its Quary, Stalking Begins

[Ron Baalke]

Dolores Beasley/Erica Hupp
Headquarters, Washington                       April 27, 2005
(Phone: 202/358-1753/1237)

D.C. Agle
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/393-9011)

RELEASE: 05-108

NASA'S DEEP IMPACT SPACECRAFT SPOTS ITS QUARRY, STALKING BEGINS

Sixty-nine days before it gets up-close-and-personal with a comet, NASA's Deep 
Impact spacecraft successfully photographed its quarry, comet Tempel 1, at a 
distance of 39.7 million miles.

The image, the first of many comet portraits it will take over the next 10 weeks, 
will aid Deep Impact's navigators, engineers and scientists as they plot their 
final trajectory toward an Independence Day encounter.

"It is great to get a first glimpse at the comet from our spacecraft," said Deep 
Impact principal investigator, Dr. Michael A'Hearn of the University of Maryland, 
College Park, Md. "With daily observations beginning in May, Tempel 1 will become 
noticeably more impressive as we continue to close the gap between spacecraft and 
comet. What is now little more than a few pixels across will evolve by July 4 into 
the best, most detailed images of a comet ever taken," he added.

The ball of dirty ice and rock was detected on April 25 by Deep Impact's Medium 
Resolution Instrument on the very first attempt. While making the detection, the 
spacecraft's camera saw stars as dim as 11th visual magnitude, more than 100 times 
dimmer than a human can see on a clear night.

"This is the first of literally thousands of images we will take of Tempel 1 for 
both science and navigational purposes," said deputy program manager Keyur Patel at 
NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Our goal is to impact a 39 inch 
long spacecraft into about a 4 mile wide comet that is bearing down on it at 6.3 
miles per second, while both are 83 million miles away from Earth. By finding the 
comet as early and as far away as we did is a definite aid to our navigation."

Deep Impact is comprised of two parts, a "flyby" spacecraft and a smaller "impactor." 
The impactor will be released into the comet's path for a planned high-speed 
collision on July 4. The crater produced by the impact could range in size from the 
width of a large house up to the size of a football stadium and from 2 to 14 stories 
deep. Ice and dust debris will be ejected from the crater, revealing the material 
beneath.

The Deep Impact spacecraft has four data collectors to observe the effects of the 
collision - a camera and infrared spectrometer comprise the High Resolution Instrument, 
a Medium Resolution Instrument, and a duplicate of that camera on the impactor (called 
the Impactor Targeting Sensor-ITS) that will record the vehicle's final moments before 
it is run over by comet Tempel 1 at a speed of about 23,000 miles per hour.

The overall Deep Impact mission management for this Discovery class program is conducted 
by the University of Maryland. Deep Impact project management is handled by the Jet 
Propulsion Laboratory. The spacecraft was built for NASA by Ball Aerospace & Technologies 
Corporation, Boulder, Colo. 

To view the image on the Internet, visit:

http://www.nasa.gov/deepimpact/

For more information about Deep Impact on the Internet, visit:

http://www.nasa.gov/deepimpact

For more information about NASA on the Internet, visit:

http://www.nasa.gov

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