LOS ANGELES  — Images captured by an Arizona telescope may show NASA's missing $159 million Contour spacecraft broken in two pieces as it hurtles away from Earth, the mission director said Friday.

The fate of the comet-chasing mission had yet to be confirmed, but mission director Robert Farquhar said he was discouraged by the news.

"I'll be real honest, I'm not very optimistic," Farquhar said from Johns Hopkins University's Applied Physics Laboratory, which manages the mission for the National Aeronautics and Space Administration.

Images taken Friday by a telescope on Kitt Peak show two parallel trails near one of the predicted positions for the spacecraft. A processed image, little more than spots of light on a dark background to the untrained eye, was posted on the Web site of the Spacewatch Project, Lunar and Planetary Laboratory of the University of Arizona.

When the image was taken, the two objects were 155 miles apart from each other and 248,000 miles from Earth, Farquhar said. If they were pieces of the spacecraft, they were moving slightly slower than expected, he said.

Mission officials planned to attempt to have a giant radar antenna at the Arecibo observatory in Puerto Rico and the Goldstone radar station in the California desert bounce signals off the objects, Farquhar said.

That was part of an extensive effort by NASA's Deep Space Network antennas, Jet Propulsion Laboratory navigators and an array of observatories to catch a signal or definitively determine what happened.

"We have not been able to make contact," the director said. "We got our hopes raised a couple of times but they were false readings."

The spacecraft was programmed to ignite its solid-propellant rocket motor at 1:39 a.m. PDT Thursday to leave orbit and head out on a multiyear mission to explore two comets. There was no contact at that time, but it was supposed to have signaled later.

NASA continued to scan the skies with its big Deep Space Network antennas, optical telescopes and radar in search of a spacecraft. If the rocket did not fire, the spacecraft would have remained in Earth orbit.

Contour, short for Comet Nucleus Tour, was built by Johns Hopkins with assistance from Cornell University. The mission plan called for Contour to meet up with comet Encke in 2003, Schwassman-Wachmann 3 in 2006 and perhaps comet d'Arrest in 2008.

The spacecraft was launched July 3 and placed in a "parking orbit" until Thursday, when the rocket firing was to kick it out of Earth's grasp and into interplanetary space.

The spacecraft was then about 140 miles above the Indian Ocean, too low for it to be tracked by the Deep Space Network antennas during the burn. It was supposed to have signaled operators at Johns Hopkins about 45 minutes later to confirm the burn, but didn't.

Contour was developed under the National Aeronautics and Space Administration's Discovery program of quickly developed, low-cost missions. None of the previous five Discovery missions, which include 1997's Mars Pathfinder, have failed.