Tempel 1 was discovered on April 3, 1867 by Wilhelm Tempel, an astronomer working in Marseille. At the time of discovery, it approached perihelion once every 5.68 years (designations 9P/1867 G1 and 1867 II). It was subsequently observed in 1873 (9P/1873 G1, 1873 I, 1873a) and in 1879 (1879 III, 1879b). However, Tempel 1's orbit occasionally brings it sufficiently close to Jupiter to be altered, with a consequent change in the comet's orbital period. This event occurred in 1881 (closest approach to Jupiter of 0.55 AU), lengthening the orbital period to 6.5 years. Perihelion also changed, increasing by 50 million kilometers, rendering the comet far less visible from Earth. Photographic attempts during 1898 and 1905 failed to recover the comet, and astronomers surmised that it had disintegrated.
NASA is planing a deep impact with Tempel because of these changes.
If you were the powers that be would you say ( we are trying to move the comet before it hits) or would you say ( we are going to see what its made of) then change the launch date to put the push away from earth.
pulic info (or what the powers that bye want you to think) google Nasa Comet 2025