NASA's CONTOUR (COmet Nucleus TOUR) was built to study and compare the interiors of two to three comets. Contact with the spacecraft was lost after an engine burn. An investigation determined that overheating during the burn caused the spacecraft to break apart.

Complete - Unsuccessful
July 3, 2002
06:47:41 UT
Science Targets
Comets 2P/Encke


Fuzzy composite image of deep space shows two streaks that indicate the spacecraft broke apart.
The two sets of circled streaks on this composite indicate the CONTOUR spacecraft broke into two pieces. The images were taken by Jim Scotti with the Spacewatch 1.8-meter telescope at Kitt Peak in Arizona on Aug. 16, 2002. Credit: Spacewatch / Lunar and Planetary Laboratory / University of Arizona

CONTOUR was designed to fly by at least two comets with the goal of compiling topographical and compositional maps, sending back imagery, and collecting data on the structure and composition of their comas. Two comets were selected for the primary mission flybys: 2P/Encke (Nov. 12, 2003) and 73P/Schwassmann-Wachmann-3 (June 19, 2006). A third flyby of 6P/d’Arrest (Aug. 16, 2008) was considered for an extended mission.

The spacecraft was successfully launched to a high apogee orbit with a period of five-and-a-half days. Controllers implemented at least 23 orbital maneuvers during the next 43 days and 25 orbits to position CONTOUR properly for its planned burn to heliocentric orbit. On that day, Aug. 15, 2002, at 08:49 UT, its solid propellant apogee motor fired as the spacecraft was approaching perigee over the Indian Ocean and out of radio contact. CONTOUR was never heard from again.

An investigation determined the spacecraft had broken up during its burn. It probably suffered structural failure due to plume heating as its main engine was firing, caused either by problems in the design of the probe or the solid rocket motor itself.


CONTOUR’s target comets had diverse physical characteristics. They were selected because they would be relatively close to Earth during each encounter.

Evolved yet active, Encke has been observed at more apparitions than any other comet, even Halley. Encke takes about three years to orbit the Sun. Encke has traveled this orbit for thousands of years, so its continued activity is rather puzzling.

Schwassmann-Wachmann 3 was discovered in 1930. Its activity was predictable until the mid-1990s, when it split into several pieces. The breakup offered the possibility of seeing relatively fresh, unaltered surfaces and evidence of materials inside the comet nucleus.


Illustrated diagram of the CONTOUR spacecraft
The CONTOUR spacecraft. Credit: NASA/JHUAPL

Simple and compact, CONTOUR has few hinged and movable parts; a body-mounted solar array; and a mission geometry suitable for fixed, passive antennas. Operators point the instruments and antennas by moving the spacecraft. A layered shield of Nextel and Kevlar protects CONTOUR from speeding dust and particles near the nucleus.

Nation United States of America (USA)
Objective(s) Comet flyby
Spacecraft Designation 2002-034A,
Spacecraft Mass 2,140 pounds (970 kilograms)
Mission Design and Management NASA / JHUAPL
Launch Vehicle Delta 7425-9.5 (no. D292)
Launch Date and Time July 3, 2002 / 06:47:41 UT
Launch Site Cape Canaveral, Fla. / SLC-17A
Scientific Instruments 1. Remote Imager/Spectrograph (CRISP)
2. Forward Imager (CFI)
3. Neutral Gas Ion Mass Spectrometer (NGIMS)
4. Dust Analyzer (CIDA)

The spacecraft had an 8-sided body; 2 meters (6 feet) tall; 2 meters wide.

Total weight: 970 kilograms (2,138 pounds)

  • Dry spacecraft: 387 kilograms
  • Solid rocket motor: 503 kilograms
  • Hydrazine fuel: 80 kilograms

Two modes of operation: Spin-stabilized cruise mode, and a precision, 3-axis stabilized encounter mode. CONTOUR was designed for solar distances up to about 121 million miles (195 million kilometers). It carried two, 5-gigabit solid-state data recorders to store data for transmission to Earth.

Science Instruments

CONTOUR Forward Imager (CFI)

  • Locates comet on approach
  • Snaps color pictures of gas, dust jets near nucleus

Mass: 9.7 kg (21 pounds)
Power: 10 watts (average) Supplier: Johns Hopkins University Applied Physics Laboratory

CONTOUR Remote Imager/Spectrograph (CRISP)

  • Takes high-resolution photos of nucleus
  • Maps ice and rock types on surface

Mass: 26.7 kg (59 pounds)
Power: 45 watts (average)
Supplier: Johns Hopkins University Applied Physics Laboratory

Neutral Gas and Ion Mass Spectrometer (NGIMS)

  • Counts and analyzes atoms, molecules and ions around nucleus

Mass: 13.5 kg (30 pounds) Power: 47 watts (average)
Supplier: NASA/Goddard Space Flight Center

Comet Impact Dust Analyzer (CIDA)

  • Determines composition of dust surrounding nucleus

Mass: 10.5 kg (23 pounds)
Power: 13 watts (average)
Supplier: von Hoerner & Sulger, GmbH

The Team

Principal Investigator: Dr. Joseph Veverka, Cornell University

Project Management, Spacecraft Development and Mission Operations: The Johns Hopkins University Applied Physics Laboratory

Navigation and Deep Space Network (DSN) Support: NASA Jet Propulsion Laboratory

Science Team:18 co-investigators from universities, industry and government agencies in the U.S. and Europe

CONTOUR was the sixth mission in NASA’s innovative Discovery Program of low-cost, highly focused scientific exploration projects. Other Discovery missions to small bodies include Near Earth Asteroid Rendezvous (NEAR) — the first mission to orbit and land on an asteroid — the Stardust and Deep Impact comet studies, and the Dawn asteroid-orbiter mission.

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