Deep Impact Kicks Off Fourth of July With Deep Space Fireworks
This image shows the initial ejecta that resulted when NASA's Deep Impact probe collided with comet Tempel 1.
+ Full image and caption
July 04, 2005
After 172 days and 431 million kilometers (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 a.m. 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. At 1:57 a.m. EDT, an image
from the spacecraft's medium resolution camera 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 a.m. 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 10 kilometers
per second (6.3 miles per second) collision with comet Tempel 1, the
Deep Impact flyby spacecraft was monitoring events from nearby. For the
following14 minutes the flyby collected and downlinked data as the comet
loomed ever closer. Then, as expected at 2:05 a.m. EDT, the flyby stopped
collecting data and entered a defensive posture called shield mode where
its dust shields protect the spacecraft's vital components during its closest
passage through the comet's inner coma. Shield mode ended at 2:32 a.m. EDT
when mission control re-established the link with the flyby spacecraft.
"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."
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.
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.
For information about Deep Impact on the Internet, visit http://www.nasa.gov/deepimpact.
DC Agle (818) 393-9011/JPL
Dolores Beasley (202) 358-1753
NASA Headquarters, Washington
Lee Tune (301) 405-4679
University of Maryland, College Park
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