Efforts to communicate with CONTOUR ended shortly after noon today without a signal from the NASA spacecraft, and mission managers say they will not try to contact the silent probe again.

"Given what we suspected about CONTOUR's condition, and that we haven't received a signal after several contact attempts, we don't believe the spacecraft is recoverable," says Edward Reynolds, CONTOUR project manager at the Johns Hopkins Applied Physics Laboratory (APL), which manages the CONTOUR mission for NASA. "At this point the project will recommend to NASA that efforts to contact the spacecraft should end, and the project will formally close down."

CONTOUR spacecraft

Launched July 3, 2002, CONTOUR fell silent after firing its onboard STAR 30 solid-propellant rocket motor on Aug. 15, during a maneuver to boost the spacecraft from a parking orbit around Earth. Ground-based telescope ../../../images taken shortly after showed three objects near CONTOUR's expected path, indicating CONTOUR had broken up near the scheduled end of the burn. Without data from the spacecraft, however, the mission team could only infer whether CONTOUR was fatally damaged. Attempts to contact the craft in the weeks after the anomaly proved unsuccessful.

(A NASA-appointed panel, led by NASA Chief Engineer Theron M. Bradley Jr., is investigating potential causes of the mishap.)

CONTOUR team members planned the final contact effort for this week, when they believed the spacecraft's multidirectional pancake beam antenna would be better positioned to receive signals from Earth. On Dec. 17, and again this morning, mission operators at APL sent several "transmit" commands through NASA's Deep Space Network (DSN) antennas toward the suspected location of the largest piece, thought to be the bulk of the spacecraft, about 42.5 million miles (68 million kilometers) from Earth. After 16 total hours of sending and watching, no signal came back.

Reynolds says the silence almost certainly means the end of a mission and a spacecraft that, up until Aug. 15, was operating wonderfully. In the six weeks after launch, mission operators and navigators guided the solar-powered craft through 23 propulsive maneuvers, positioning it precisely for the 50-second rocket burn that was to send CONTOUR toward close-up encounters with at least two comets. Several technical aspects of CONTOUR itself - such as an innovative non-coherent navigation system - met controllers' high expectations and could find places in future spacecraft designs. Also, new developments within CONTOUR's imaging instruments are being incorporated into upcoming missions to Mercury, Mars and Pluto.

"A lot of people worked hard to build CONTOUR and prepare for this mission, and we're deeply disappointed that it didn't work out," Reynolds says. " The interest in CONTOUR was remarkable; people from around the world told us how excited they were about the chance to learn more about comets than any mission had taught before. We hope this team will have another opportunity to make that happen."

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