[meteorite-list] Deep Impact's Launcher Begins To Take Shape

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Nov 23 12:14:58 2004
Message-ID: <200411231714.JAA26475_at_zagami.jpl.nasa.gov>

http://www.spaceflightnow.com/delta/d311/041122stacking.html

Deep Impact's launcher begins to take shape
BY JUSTIN RAY
SPACEFLIGHT NOW
November 22, 2004

The Delta launch team at Cape Canaveral had little time to rest after
Saturday's successful liftoff of NASA's Swift observatory as the crew
begin erecting another rocket Monday that will dispatch an extraordinary
mission to Comet Tempel 1 on December 30.

The $320 million Deep Impact mission will rendezvous with the comet on
July 4 and fire an 820-pound copper bullet into the heart of Tempel 1,
carving out a stadium-sized crater. Sophisticated instruments and
cameras on the Deep Impact's mothership will record the blast and
analyze the materials excavated.

"We're doing this to discover the comet's structure and makeup," said
Rick Grammier, NASA's Deep Impact project manager. "This is like
swinging an 820-pound slug of copper at this thing and seeing what
happens."

Buried inside the hearts of these rocky snowballs are pristine building
blocks left over from the solar system's creation. Deep Impact will
provide an unprecedented glimpse at the comet's interior materials that
have been frozen in time for billions of years.

"What we see coming out of comets as gas and dust is stuff that has been
modified because it is very near the surface, and every time the comet
goes around the sun the surface gets heated. So there have been changes
in the surface layers...What I really want to do is figure out how
different the surface is from what's inside," said Michael A'Hearn,
astronomer from the University of Maryland and the Deep Impact principal
investigator.

Scientists expect the materials thrown out of the freshly bored hole
will settle within a few minutes, permitting good visibility into the
crater. The mothership has less than 14 minutes to make its observations
while zooming toward the comet before passing by Tempel 1 at a distance
of 300 miles.

The first stage of the Delta 2 rocket to launch Deep Impact was hoisted
atop pad 17B on Monday, just 48 hours after another Delta 2 roared away
from neighboring pad 17A carrying NASA's Swift gamma-ray observatory.

The blue-green stage was hauled to the pad on a specially-outfitted
trailer. A crane in the pad's mobile service tower grabbed the stage and
lifted it upright. The tower then wheeled into position over the pad
deck, allowing the stage to be lowered into the pedestal mount.

The nine strap-on solid rocket boosters will be attached to the stage in
sets of three on Tuesday, next Monday and next Wednesday.

The second stage is scheduled for mating atop the first stage next Friday.

Meanwhile, the Deep Impact spacecraft is undergoing final preparations
for launch at the Astrotech Space Operations facility near Titusville.
It arrived in Florida from the Ball Aerospace factory in Boulder,
Colorado, on October 23.

Technicians are performing the Functional and Mission Readiness testing,
which is scheduled for completion Tuesday. The tests involve the main
mothership, the comet impactor, science instruments and the basic
subsystems.

The high gain antenna used for spacecraft communications will be
installed next Monday. The solar arrays will then be stowed and an
illumination test performed as a final check of its performance on
Tuesday. Deep Impact will be set for fueling the following week.

After being joined with the solid-propellant motor that serves at the
Delta's third stage, the spacecraft will be transported to pad 17B and
placed atop the rocket.

Launch is scheduled for 2:39:42 p.m. EST (1939:42 GMT) December 30, the
opening of a 30-day window to send the craft on its trajectory to the
comet.

Project officials say there is no suitable backup launch opportunity if
Deep Impact missed its window to Tempel 1.

Discovered in 1867 by Ernst Wilhelm Leberecht Tempel, this comet
currently circles the sun every 5.5 years. Its orbit lies between Mars
and Jupiter, providing the Deep Impact mission a perfect target for
reaching with a modest launch vehicle, striking at high speed and being
visible from Earth at impact about 80 million miles away.
Received on Tue 23 Nov 2004 12:14:53 PM PST