The two spacecraft of NASA's Deep Impact mission, dubbed Flyby and Impactor by their makers, are set to launch Wednesday atop a Boeing Delta 2 rocket, their mission: To unlock the inner secrets of comets. .

"All I can do now is worry and hope," said Deep impact principal investigator Michael A'Hearn, of the University of Maryland, during a telephone interview. "And then watch it go."

Deep Impact is currently scheduled for a 1:47 p.m. EST (1847 GMT) liftoff from Launch Pad 17B at Cape Canaveral Air Force Station in Florida. If all goes well, the mission's two spacecraft will tag team Comet Tempel 1 on July 4, with Impactor set to slam into the icy wanderer while Flyby looks on.

Built for NASA by Ball Aerospace and Technologies Corp., Deep Impact is designed to give researchers their first glimpse of the inner workings of a comet. By crashing Impactor into Tempel 1, thought to be a rather typical example of comets, researchers hope to glimpse pristine material that have not changed since the formation of the solar system.

"The interesting part of this mission is that we don't really know what to expect," said Don Yeomans, a senior research scientist with the Deep Impact mission at NASA's Jet Propulsion Laboratory (JPL). "But no matter what happens, we'll observe the phenomena."...

NASA's Deep Impact spacecraft was successfully launched on a Delta 2 Wednesday afternoon but almost immediately went into a safe mode that project officials say should not jeopardize the mission. The Delta 2 7925 lifted off from Cape Canaveral at 1:47:08 pm EST (1847:08 GMT); its payload, Deep Impact, separated from the booster's upper stage about 35 minutes after liftoff. While the launch appeared to go well, the spacecraft went into a protective safe mode shortly after separation, limiting communications with the ground to a low-data-rate mode. Project engineers said late Wednesday that the safe mode was apparently triggered when sensors noted temperatures in the spacecraft's propulsion system briefly exceeded an upper limit. Engineers believed that there is no damage to the spacecraft and that the problem can be quickly resolved. Deep Impact will fly past the comet Tempel 1 in July, deploying a probe that will collide with the comet's nucleus on July 4.

PASADENA, Calif. Jan 13, 2005 — NASA's Deep Impact comet-busting spacecraft emerged from "safe mode" and was operating normally, the space agency said Thursday.

The spacecraft went into protective mode after launch Wednesday from Cape Canaveral, Fla., when it detected higher-than-expected temperatures in its propulsion system.

Safe mode shuts down all but essential systems while the spacecraft awaits new commands from controllers.

While in safe mode, Deep Impact did perform essential tasks including deploying and locking its solar panels, NASA said. The craft was receiving power and was properly oriented in space...