Thursday, November 4, 2010
Comet Hartley 2 Flyby
These photos are from the EPOXI spaceship's close flyby of comet Hartley 2 today. Comet Hartley 2 has been a bit of a disappointment visually from urban areas, but it has spawned some really beautiful low velocity meteors over the past several weeks, including one I blogged about recently (which I mistook for an Orionid).
Here's the NASA report.
PASADENA, Calif. – 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.
For those who wonder why NASA is spending so much money and effort determining the composition of comets and asteroids, this would be the answer. These two large asteroids passed well within the moon's orbit on the same day, September 8th of this year. Knowing as much as we can about asteroids and comets should be one of our very top priorities as a society. If you don't believe me, just ask a dinosaur.