[meteorite-list] JPL To Assist On CONTOUR Mission
From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:01:35 2004
JPL To Assist On Comet Mission
June 21, 2002
Contour prepares for July 1 launch
Set to visit and study at least two comets, NASA's Comet Nucleus Tour
(Contour) should provide the first detailed look at the differences
between these primitive building blocks of the solar system, and
answer questions about how comets act and evolve. The mission is
being prepared for a July 1 launch from Kennedy Space Center.
JPL will provide navigation and Deep Space Network support for the
mission, and JPL astronomer Dr. Don Yeomans, manager of NASA's
Near Earth Objects Program Office, is a Contour science team
Contour is scheduled to lift off on a three-stage Boeing Delta II
expendable launch vehicle during a 25-day launch window that opens
July 1 at 2:56 a.m. Eastern time. The spacecraft will orbit Earth until
Aug. 15, when it should fire its main engine and enter a comet-chasing
orbit around the sun.
Contour's flexible four-year mission plan includes encounters with
comets Encke, Nov. 12, 2003, and Schwassmann-Wachmann 3, June 19,
2006. Contour will examine each comet's "heart," or nucleus, which
scientists believe is a chunk of ice and rock, often just a few kilometers
across and hidden from Earth-based telescopes beneath a dusty atmosphere
and long tail.
"The Contour mission will be NASA's second mission dedicated solely
to exploring these largely unknown members of our solar system," said
Dr. Colleen Hartman, director of the Solar System Exploration Division
at NASA Headquarters in Washington. "Contour joins our other operating
mission, Stardust, which is on its way to bring a sample of a comet
back to Earth, and Deep Impact will launch next year. These missions
all help us find answers to the fundamental questions of how our planet
may have formed and evolved, and how life may have begun on Earth
and perhaps elsewhere in the Universe."
Comets are "the remnants of the outer solar system formation
process," Yeomans said in a prelaunch briefing. The instruments on
Contour, he added, will determine the chemical composition of the
comet - helping in turn to determine whether a comet might have
brought much of the Earth's oceans and its atmosphere, as well as
carbon-based molecules, to the Earth's surface.
Yeomans said the "genius" of the Contour mission design is that
"we're not chasing comets around the solar system; we're using Earth
swingbys to allow them to come to us." The encounters are taking place
very close to Earth (less than 50 million kilometers or 31 million
miles), which, he said, "makes communications easy, but it also allows
professional, ground-based astronomers, as well as amateur
astronomers and the public, to participate in a very meaningful way."
The comets will be bright enough to be seen with binoculars about the
same time as Contour is looking at the comet's nucleus, he said.
Members of the JPL navigation team include Tony Taylor, Bobby
Williams, George Lewis, Cliff Helfrich, Eric Carranza, Don Han,
Ramachand Bhat and Jamin Greenbaum.
The eight-sided, solar-powered craft will fly as close as 100 kilometers
(62 miles) to each nucleus, at top speeds that could cover the 56
kilometers between Washington and Baltimore in two seconds. A five-layer
dust shield of heavey Nextel and Kevlar fabric protects the compact
probe from the comet dust and debris.
"Comets are the solar system's smallest bodies, but among its biggest
mysteries," said Dr. Joseph Veverka, Contour's principal investigator
from Cornell University, Ithaca, N.Y. "We believe they hold the most
primitive materials in the solar system and that they played a role in
shaping some of the planets, but we really have more ideas about
comets than facts. Contour will change that by coming closer to a
comet nucleus than any spacecraft ever has before and gathering
detailed, comparative data on these dynamic objects."
Contour's four scientific instruments will take pictures and measure
the chemical makeup of the nuclei while analyzing the surrounding gases
and dust. Its main camera, the Contour Remote Imager/Spectrograph,
will snap high-resolution digital images showing car-sized rocks and
other features on the nucleus as small as 4 meters (about 13 feet)
across. The camera will also search for chemical "fingerprints" on the
surface, which would provide the first hard evidence of comet nuclei
Encke has been seen from Earth more than any other comet; it's an
"old" body that gives off relatively little gas and dust but remains more
active than scientists expect for a comet that has passed close to the
sun thousands of times. Schwassmann-Wachmann 3, on the other hand,
was discovered just 70 years ago and recently split into several pieces,
intriguing scientists with hopes that Contour might see fresh, unaltered
surfaces and materials from inside the comet.
Contour is the sixth mission in NASA's Discovery Program of lower
cost, scientifically focused exploration projects. Johns Hopkins
University's Applied Physics Laboratory manages the mission, and also
built the spacecraft and its two cameras. NASA's Goddard Space Flight Center
provided Contour's neutral gas/ion mass spectrometer and von Hoerner
& Sulger, GmbH, Schwetzingen, Germany, built the dust analyzer.
For more information, visit
Received on Mon 24 Jun 2002 11:59:59 AM PDT