NASA mission to asteroid gets help from Hubble Space Telescope (w/ Video)

Oct 08, 2010

(PhysOrg.com) -- NASA's Hubble Space Telescope has captured images of the large asteroid Vesta that will help scientists refine plans for the Dawn spacecraft's rendezvous with Vesta in July 2011.

Scientists have constructed a video from the images that will help improve pointing instructions for Dawn as it is placed in a polar orbit around Vesta. Analyses of Hubble images revealed a pole orientation, or tilt, of approximately four degrees more to the asteroid's east than scientists previously thought.

This means the change of seasons between the southern and northern hemispheres of Vesta may take place about a month later than previously expected while Dawn is orbiting the asteroid. The result is a change in the pattern of sunlight expected to illuminate the asteroid. Dawn needs solar illumination for imaging and some mapping activities.

NASA's Hubble Space Telescope snapped these images of the asteroid Vesta in preparation for the Dawn spacecraft's visit in 2011. Image credit: NASA/ESA/STScI/UMd

"While Vesta is the brightest asteroid in the sky, its small size makes it difficult to image from Earth," said Jian-Yang Li, a scientist participating in the Dawn mission from the University of Maryland in College Park. "The new Hubble images give Dawn scientists a better sense of how Vesta is spinning because our new views are 90 degrees different from our previous images. It's like having a street-level view and adding a view from an airplane overhead."

The recent images were obtained by Hubble's 3 in February. The images complemented previous ones of Vesta taken from ground-based telescopes and Hubble's Wide Field and Planetary Camera 2 between 1983 and 2007. Li and his colleagues looked at 216 new images -- and a total of 446 Hubble images overall -- to clarify how Vesta was spinning. The journal Icarus recently published the report online.

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Chris Russell, principal investigator for NASA's Dawn mission, explains how new images obtained by NASA's Hubble Space Telescope help his mission refine plans for Dawn's rendezvous with the large asteroid Vesta in July 2011.

"The new results give us food for thought as we make our way toward Vesta," said Christopher Russell, Dawn's principal investigator at the University of California, Los Angeles. "Because our goal is to take pictures of the entire surface and measure the elevation of features over most of the surface to an accuracy of about 33 feet, or the height of a three-story building, we need to pay close attention to the solar illumination. It looks as if Vesta is going to have a late northern spring next year, or at least later than we planned."

Launched in September 2007, Dawn will leave Vesta to encounter the dwarf planet Ceres in 2015. Vesta and Ceres are the most massive objects in the main belt between Mars and Jupiter. Scientists study these celestial bodies as examples of the building blocks of terrestrial planets like Earth. Dawn is approximately 134 million miles away from Vesta. Next summer, the spacecraft will make its own measurements of Vesta's rotating surface and allow mission managers to pin down its axis of spin.

"Vesta was discovered just over 200 years ago, and we are excited now to be on the threshold of exploring it from orbit," said Bob Mase, Dawn's project manager at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "We planned this mission to accommodate our imprecise knowledge of Vesta. Ours is a journey of discovery and, with our ability to adapt, we are looking forward to collecting excellent science data at our target."

The Dawn mission is managed by JPL for NASA's Science Mission Directorate at the agency's headquarters in Washington. Orbital Sciences Corporation of Dulles, Va., designed and built the spacecraft. Several international space organizations are part of the mission team.

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User comments : 4

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tigger
not rated yet Oct 08, 2010
Info below that helps somewhat when talking numbers, like accuracy of 33 feet... which would be crap if the thing was 100 feet in diameter wouldn't it? Yes yes, we live in a digital age where I can look these things up, but not everyone has the time and throwing numbers out there without context is lazy and poor journalism... if it was in a print medium you'd be pissed off because 33 feet means nothing without context.

Without further ado...

Vesta has a diameter of 525 kilometers (326 miles). It rotates about its axis in 5.34 hours.
yyz
not rated yet Oct 08, 2010
"While Vesta is the brightest asteroid in the sky...."

Interestingly, near-Earth asteroid Apophis is expected to briefly (a few hours) outshine Vesta as it streaks by us in 2029: http://en.wikiped...Earth.29
Pkunk_
not rated yet Oct 09, 2010
"While Vesta is the brightest asteroid in the sky...."

Interestingly, near-Earth asteroid Apophis is expected to briefly (a few hours) outshine Vesta as it streaks by us in 2029: http://en.wikiped...Earth.29


Gasp. you mean to it will actually MISS us ?
Quantum_Conundrum
not rated yet Oct 09, 2010
"While Vesta is the brightest asteroid in the sky...."

Interestingly, near-Earth asteroid Apophis is expected to briefly (a few hours) outshine Vesta as it streaks by us in 2029:


I'm sure all the lunatics from 1999, y2k, and then soon 2012 will shift their hysteria to 2029 as the end of humanity, once 2012 is shown to be a hoax as well.