NASA Deep Impact spacecraft visits another comet
This black-and-white image of the comet Hartley 2 provided by NASA was sent from the NASA EPOXI Mission Deep Impact spacecraft, which passed within 435 miles of the comet at its closest point, and was received at Jet Propulsion Laboratory in Pasadena, Calif., Thursday, Nov. 4, 2010. The comet is estimated to be 1.4 miles (2.2 kilometers) long, and weigh about 280 million metric tons. (AP Photo NASA/JPL-Caltech/University of Maryland)
This image provided by NASA/JPL-Caltech shows an artist's conception of NASA's Deep Impact spacecraft that has an appointment with comet Hartley 2 on thursday Nov. 4, 2010. The encounter will mark only the fifth time a comet has been photographed up close -- and the first time two comets have been imaged by the same instruments and same spatial resolution, according to Jet Propulsion Laboratory. (AP Photo/NASA/JPL-Caltech)
Project manager Tim Larson, left, and deputy project manager Don Sweetnam celebrate as the first images from the NASA Deep Impact spacecraft that passed within 435 miles of the Comet Hartley 2 are seen for the first time, at mission control at Jet Propulsion Laboratory in Pasadena, Calif., Thursday, Nov. 4, 2010. (AP Photo/Reed Saxon)
PASADENA, Calif. — A NASA spacecraft survived a rendezvous with a small comet Thursday, beaming pictures back to Earth that gave scientists a rare close-up view of its center.
Mission controllers burst into applause upon seeing images from the flyby that revealed a peanut-shaped comet belching jets of poisonous gases.
“It’s hyperactive, small and feisty,” said mission scientist Don Yeomans of the NASA Jet Propulsion Laboratory.
The close encounter occurred 13 million miles away from Earth when the Deep Impact craft, hurtling through space, flew within 435 miles of comet Hartley 2. It’s the fifth time that a comet’s core has been viewed up close.
Scientists are interested in comets because they’re icy leftovers from the formation of the solar system about 4.5 billion years ago. Studying them could provide clues to how Earth and the planets formed and evolved.
The flyby is actually an encore mission for Deep Impact. It set off cosmic fireworks on July 4, 2005, when it fired a copper probe that crashed into comet Tempel 1. The high-speed collision spewed a cloud of debris into space, giving scientists their first peek of the interior.
After the $333 million comet-buster, NASA recycled Deep Impact for a new mission to visit another comet. It was supposed to target comet Boethin in 2008, but it was nowhere to be found. Scientists theorized the comet may have broken up into small pieces.
Deep Impact was then redirected to Hartley 2. Roughly 1½ miles wide, Hartley 2 is the smallest comet to be photographed up close. On its way there, the craft spent several months scanning a cluster of nearby stars with known planets circling them.
While its latest task lacks the Hollywood drama of the Tempel 1 crash, researchers still consider it an important mission. Unlike in 2005, viewers could not see Thursday’s comet encounter in real time since the craft’s antenna was not pointed at Earth as it flew past Hartley 2.
“There are a lot of open questions about comets and their life cycle,” said project manager Tim Larson of JPL, which manages the $42 million encore mission. “We have so little data that every time we have an opportunity to go near a comet, it’s a chance to expand our knowledge.”
Since September, Deep Impact has been stalking Hartley 2 like a paparazzo, taking images every 5 minutes and gathering data. It’s the first craft to visit two comets.
The flyby images add to scientists’ cometary photo album, said astronomer David Jewitt of the University of California, Los Angeles, who had no role in the project.
“We’re visual animals and nothing seems wholly real to us until we have a nice picture of it,” Jewitt said.
Hartley 2 passed within 11 million miles of Earth on Oct. 20 — the closest it has been to our planet since its discovery in 1986.
British-born astronomer Malcolm Hartley, who discovered the comet, said he never imagined a spacecraft would get so close to his namesake find.
“When I saw the comet, it was millions and millions of kilometers away,” he said. “I’m extremely excited and feel very privileged. After all, I only discovered it.”
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Online:
Comet mission: http://epoxi.umd.edu/
