NASA's comet-slamming Deep Impact spacecraft is generally in good health though a minor glitch has cropped up with one camera, mission officials said Friday.

The craft launched Jan. 12 and is expected to reach comet Tempel 1 on July 4. Fireworks are expected as the spacecraft sends a probe into the comet. The event will be recorded by cameras and other instruments on the mothership and may even be visible to backyard skywatchers.

Several tests have been performed since launch.

The spacecraft's high gain antenna, which will relay images and data of the collision, was activated and is operating properly, according to a NASA statement. A planned trajectory correction successfully refined the spacecraft's flight.

Another event during commissioning phase was the bake-out heating of the spacecraft's High Resolution Instrument (HRI) to remove normal residual moisture from its barrel. The moisture was a result of absorption into the structure of the instrument during the vehicle's last hours on the launch pad and its transit through the atmosphere to space.

At completion of the bake-out procedure, test images were taken through the HRI. These images indicate the telescope has not reached perfect focus.

NASA has formed a team to investigate. It might be possible to bring the camera into full focus.

"This in no way will affect our ability to impact the comet on July 4," said Rick Grammier, Deep Impact project manager at NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif. "Everyone on the science and engineering teams is getting very excited and looking forward to the encounter."

The craft's Medium Resolution Instrument (MRI) and a duplicate camera on the Impactor Targeting Sensor (ITS) are operating as expected.

"We are very early in the process of examining the data from all the instruments. It appears our infrared spectrometer is performing spectacularly, and even if the spatial resolution of the High Resolution Instrument remains at present levels, we still expect to obtain the best, most detailed pictures of a comet ever taken."

Deep Impact is comprised of two parts, a flyby spacecraft and a smaller impactor," said Michael A'Hearn of the University of Maryland. "The impactor will be released into the comet's path for the planned high-speed collision. The crater produced by the impactor is expected to range from the width of a house up to the size of a football stadium and be from two to 14 stories deep. Ice and dust debris will be ejected from the crater revealing the material beneath.

Along with the imagers aboard the spacecraft, NASA's Hubble, Spitzer and Chandra space telescopes, along with the largest telescopes on Earth, will observe the effects of the material flying from the comet's newly formed crater.

It will be the first glimpse of material freshly excavated from the inside of a comet.