SPACE The comet-chasing CONTOUR spacecraft appears to have broken into two pieces sometime after its course-altering rocket engine fired early Thursday morning, a NASA official said Friday evening.
A ground-based telescope photograph of two unknown objects about 155 miles (250 kilometers) apart appeared to be pieces of CONTOUR (Comet Nucleus Tour). The objects were spotted along the path the spacecraft would have traveled had the engine fired.
"We haven't given up by any means, but the news is very discouraging," said Mission Director Robert Farquhar of the Applied Physics Laboratory (APL) of Johns Hopkins University. "Although this is not conclusive, it is not very encouraging."
Farquhar said more investigation was needed to confirm whether the objects were parts of CONTOUR. The two pieces were about 250,000 miles away from Earth, heading into deep space, and do not pose any danger to the planet or to other Earth-orbiting spacecraft.
There was no clear cause for the possible accident, but Farquhar said the craft's engine had almost certainly fired and that the probe was no longer in Earth orbit. Officials had said Thursday the craft might never have left the gravitational grip of the planet.
Despite the possible catastrophe, a concerted search effort will continue at least through Monday. NASA's Deep Space Network and the Arecibo Observatory will scan the skies for radio signals in the hopes that the 2,138-pound (970-kilogram) craft phones home and reports it is healthy and heading for a comet rendezvous.
Other telescope will
continue visual searches for the spacecraft."It's not the best evening for the CONTOUR mission," Farquhar said during a teleconference with reporters that began around 5:30 EDT Friday.
The mission director said he had remained confident most of Thursday that the spacecraft was in good health. "Up until a little while ago I had a whole lot of hope," he said.
What should have happened
APL built CONTOUR and leads the $159 million mission under NASA direction. It is a Discovery-class mission, designed at relatively low cost for a highly specific task.
The craft launched July 3 into an elliptical orbit around Earth. At 4:49 a.m. EDT, Thursday the probe was supposed to fire its STAR 30 BP rocket motor to shoot it out of Earth's gravitational pull. This plan saved $10 million compared to launching the spacecraft directly from Earth to deep space. The engine firing was a critical procedure but not unusual and similar engines have powered other spacecraft.
About 45 minutes later, CONTOUR should have sent a signal to be picked up by NASA's Deep Space Network of radio antennas around the world. No signal was ever received.
The craft's
mission is to take close-up photos and gather other data on two or possibly three comets. On the off chance that CONTOUR is in good health but simply cannot transmit, it could be on its way to comet Encke, it's first target. If so, the only likely way to detect it would be through the Deep Space Network.
It is not unheard of for spacecraft to go quiet at critical junctures, only to turn up healthy later.
In fact, an earlier APL-run mission, the Near Earth Asteroid Rendezvous, disappeared in 1998 after a course-correcting burn did not occur. Contact was re-established two days later and the craft completed a successful mission.
"We got our hopes raised a couple of times," Farquhar said of false readings that suggested CONTOUR was calling back. "It's a roller coaster when this happens."
Just when things were going well
A loss would come just as NASA has re-emerged from some of its
darkest days and criticism over back-to-back mission disasters in 1999.In that year, Mars Climate Orbiter failed to go into orbit around the Red Planet because of a human mix-up between metric and English units. In addition, the Mars Polar Lander failed to safely reach the surface. Both missions were managed by NASA's Jet Propulsion Laboratory.
Critics faulted NASA's shift to more and cheaper missions as a contributing cause to the failures. Even NASA officials admitted as much.
But the agency gained renewed vigor and purpose with the success of the recent
Odyssey mission to Mars.While Mars missions are typically planned for launch every couple of years, comet missions are rare. Astronomers say CONTOUR would help them map out the diversity of these frozen objects, which are thought to harbor material that's gone unchanged since the birth of the solar system.
The plan was to examine comet Encke in November 2003 and Schwassmann-Wachmann 3 in June 2006. The two comets are thought to be very different.
"It would be pretty sad" if the craft does not complete its mission, said Donald Yeomans, a comet expert at JPL. "If we had to go without it we would be losing a significant amount of comet science."
If CONTOUR is lost, a replacement mission -- if ever approved -- could take several years or even a decade or more to get off the ground.
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