NASA's EPOXI mission spacecraft successfully flew past comet Hartley 2 at 7 a.m. PDT (10 a.m. EDT) Thursday, Nov. 4. Scientists say initial images from the flyby provide new information about the comet's volume and material spewing from its surface.

"Early observations of the comet show that, for the first time, we may be able to connect activity to individual features on the nucleus," said EPOXI Principal Investigator Michael A'Hearn of the University of Maryland, College Park. "We certainly have our hands full. The images are full of great cometary data, and that's what we hoped for."

EPOXI is an extended mission that uses the already in-flight Deep Impact spacecraft. Its encounter phase with Hartley 2 began at 1 p.m. PDT (4 p.m. EDT) on Nov. 3, when the spacecraft began to point its two imagers at the comet's nucleus. Imaging of the nucleus began one hour later.

"The spacecraft has provided the most extensive observations of a comet in history," said Ed Weiler, associate administrator for NASA's Science Mission Directorate at the agency's headquarters in Washington. "Scientists and engineers have successfully squeezed world-class science from a re-purposed spacecraft at a fraction of the cost to taxpayers of a new science project."

Images from the EPOXI mission reveal comet Hartley 2 to have 100 times less volume than comet Tempel 1, the first target of Deep Impact. More revelations about Hartley 2 are expected as analysis continues.

Initial estimates indicate the spacecraft was about 700 kilometers (435 miles) from the comet at the closest-approach point. That's almost the exact distance that was calculated by engineers in advance of the flyby.

"It is a testament to our team's skill that we nailed the flyby distance to a comet that likes to move around the sky so much," said Tim Larson, EPOXI project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "While it's great to see the images coming down, there is still work to be done. We have another three weeks of imaging during our outbound journey."

The name EPOXI is a combination of the names for the two extended mission components: the Extrasolar Planet Observations and Characterization (EPOCh), and the flyby of comet Hartley 2, called the Deep Impact Extended Investigation (DIXI). The spacecraft has retained the name "Deep Impact." In 2005, Deep Impact successfully released an impactor into the path of comet Tempel 1.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, manages the EPOXI mission for NASA's Science Mission Directorate. The spacecraft was built for NASA by Ball Aerospace and Technologies Corp., in Boulder, Colo.

earlier related report
Administrator's Statement on EPOXI Flyby of Comet Hartley 2
Washington DC (SPX) Nov 05 - The following is a statement from NASA Administrator Charles Bolden on the EPOXI mission's successful flyby of comet Hartley 2:

"NASA extended its pioneering exploration of the solar system today with the successful flyby of Comet Hartley 2 by our EPOXI mission. The stunning new images returned of the comet as it zoomed past the spacecraft at a relative speed of more than 27,000 mph are awe inspiring.

"The images taken and other science collected should help reveal new insights into the origins of our solar system as scientists pore over them in the months and years to come. And they are also yet another example of the incredible dedication, skill, and innovation of the engineers and scientists at NASA, and our partners, who accomplish these incredible technological feats.

"This mission represents one of NASA's most successful deep space exploration projects. The encounter with Hartley 2 today adds to the data collected by the mission during Deep Impact's prime mission to Comet Tempel 1 in 2005 and the science acquired during the successful EPOCh mission.

"EPOXI is a wonderful example of the strong collection of NASA science missions we have coming up in the next few years that will enable us to visit destinations across the solar system in new and exciting ways, look through new windows out across our vast cosmos, and expand our understanding of our own home planet. Our increased investment in science will continue to yield valuable dividends for the future.

"On behalf of the entire NASA family and interested stargazers around the world, my congratulations to the EPOXI team for a great moment of scientific exploration and discovery."