[FPSPACE] Fwd: Cornell Chronicle: Cometary rendezvous set for Valentine's Day

LARRY KLAES ljk4 at msn.com
Wed Feb 9 01:37:32 EST 2011

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From: Cornell Chronicle
Sent: 2/8/2011 9:42:48 PM
To: CUNEWS-SCIENCE-L at cornell.edu ,
Subject: Cornell Chronicle: Cometary rendezvous set for Valentine's Day
Chronicle Online e-News

Recycled spacecraft and comet fated for Valentine's Day rendezvous

Feb. 8, 2011

By Lauren Gold
lg34 at cornell.edu

In the beginning, both couples seemed meant for each other.

There was the Stardust spacecraft, launched in 1999, and her cometary
fiancée, Wild 2. Betrothed from afar, the two headed blissfully toward
a 2004 rendezvous.

Meanwhile, the comet Tempel 1, making her own solitary way around the
sun in 2005, was heading toward a more explosive relationship with the
Deep Impact spacecraft.

But alas, heavenly though the matches were -- and fruitful, with each
yielding valuable information about the evolution of the solar system
-- neither lasted. In 2006, Stardust tossed her dusty tokens of Wild 2
down to Earth for analysis and vowed to start anew. She was a little
older now; but with all her parts in good working order and adequate
fuel, she was ready for a second mission. And Tempel 1, scarred by her
violent encounter with Deep Impact, was looking for a kinder, gentler

On Valentine's Day, the two will meet. In the heat of the moment,
astronomers hope, Tempel 1 will be cajoled into yielding a few more
clues about her background. And Stardust, equipped with imaging and
dust composition analysis instruments, will relay those clues to Earth.

The expectant matchmakers:

Among the astronomers waiting patiently are Joe Veverka, professor of
astronomy and principal investigator for Stardust-NExT, the NASA
mission orchestrating the rendezvous.

The Valentine's Day flyby could yield a wealth of new information about
Tempel 1's structure and composition, Veverka said, and how its
features change with every passage around the sun.

"We know that comets lose material," he said in a recent press
conference; "But the question is 'How does the surface change, and
where does the surface change?'" Comparing the 2005 images with the new
ones -- taken one rotation around the sun later -- could provide the

Stardust could also catch a glimpse of the crater that formed when a
probe from Deep Impact crashed into Tempel 1's surface six years ago.

"That impact threw up so much ejecta that Deep Impact never saw the
crater," Veverka said. "So it could never see how big the crater is and
what [it] tells us about the mechanical properties of the surface."

That information is vital for any future mission that involves landing
a spacecraft on the surface of a comet, he said.

And finally, astronomers hope the rendezvous will provide a closer look
at some of the surface features Deep Impact saw when it zoomed by in
2005. Layered terrain, for example, could contain information about how
comet nuclei were formed; and smooth flows hint at some internal
processes that could be working their way up to change the surface.

"Deep Impact saw only about one-third of the surface," Veverka said.
"We would like to see more."

So -- as Feb. 14 approaches and other romantic souls plan candlelight
dinners, Veverka and colleagues are tracking the pair, now hurtling
toward each other at about 590,000 miles a day.

Stardust caught its first glimpse of Tempel 1 Jan. 26. It will keep its
eye on the comet as it approaches, collecting data to help mission
navigators refine its trajectory.

Close encounter:

And on Valentine's Day, as Earthbound lovers gaze into each other's
eyes, the two orbiting bodies will meet, about 120 miles apart. As they
pass, Stardust will test the density and composition of the dust
surrounding the comet and snap 72 high-resolution images.

Researchers expect to receive the data within a few hours of the
closest encounter. "The science team is awfully excited," Veverka said.

And thus, perhaps, the curtain will close on this cometary encore. But
as with all concluded affairs, there will be months -- perhaps years --
of data analysis; and ultimately, plans for the next mission.

"Comets preserve some of the most faithful information about what
happened when the solar system formed," Veverka said. "This is a step
toward the ultimate answer."

Stardust-NExT is managed by JPL, a division of the California Institute
of Technology in Pasadena, for the NASA Science Mission Directorate.
Lockheed Martin Space Systems built the spacecraft and manages
day-to-day mission operations.

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