Rick Grammer, project manager of Deep Impact, said that this small problem will in no way affect the mission of Deep Impact.
On July 4 the spacecraft will reach comet Tempel 1 and send a probe into the comet to reveal the material beneath.
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.Not only the Deep Impact spacecraft but also Hubble, Spitzer and Chandra and also the largest telescopes on Earth will observe the effects of the material flying from the newly created crater on Tempel 1.
More information at Space.com