Donald Savage
Headquarters, Washington           June 12, 2002
(Phone: 202/358-1754) 

Michael Buckley
The Johns Hopkins University Applied Physics Laboratory, 
Laurel, MD
(Phone: 240/228-7536)

RELEASE: 02-110

NASA'S CONTOUR MISSION GETS TO THE "HEART" OF COMET DIVERSITY

     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. 

CONTOUR is scheduled to lift-off from Cape Canaveral Air 
Force Station, Fla., 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. (EDT). 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."

The 8-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 heavy 
Nextel and Kevlar fabric protects the compact probe from 
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 (CRISP), 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. 
CRISP will also search for chemical "fingerprints" on the 
surface, which would provide the first hard evidence of comet 
nuclei composition. 

The targets were selected because of their diversity and 
relative closeness to Earth during encounter time -- less 
than 50 million kilometers (31 million miles) --allowing 
astronomers to make observations during the encounters. 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. 

"The key to the CONTOUR mission is to visit a diverse range 
of comets, from an evolved comet such as Encke, to a younger 
comet like SW3 or even a new comet never seen in this part of 
the solar system," said Mary C. Chiu, CONTOUR project manager 
at The Johns Hopkins University Applied Physics Laboratory 
(APL), Laurel, Md. "Our mission plan gives us that 
flexibility."

CONTOUR's orbit loops around the sun and back to Earth for 
annual "gravity swings" toward its targets; these maneuvers 
refine or revise CONTOUR's trajectory and help it reach 
several comets without using much fuel. CONTOUR will cruise 
unattended between comet encounters and Earth swingbys in a 
spin-stabilized "hibernation" mode, helping the mission 
reduce operations and communications costs. 

The $159 million CONTOUR is the sixth mission in NASA's 
Discovery Program of lower cost, scientifically focused 
exploration projects. APL manages the mission, built the 
spacecraft and its two cameras. NASA's Goddard Space Flight 
Center, Greenbelt, Md., provided CONTOUR's neutral gas/ion 
mass spectrometer and von Hoerner & Sulger, GmbH, 
Schwetzingen, Germany, built the dust analyzer. NASA's Jet 
Propulsion Laboratory, Pasadena, Calif., will provide 
navigation and Deep Space Network (DSN) support.

Additional information about CONTOUR is available on the web 
at: http://www.contour2002.org