Stock Photo - 01/28/1999 ___ Workers inside the launch tower at Pad 17_A, Cape Canaveral Air Station, guide the third stage of a Boeing Delta II rocket, and the Stardust spacecraft connected to it, through an opening to the second stage of the rocket below. The second and third stages of teh rocket will be mated next as preparations continue for liftoff on Feb. 6. Stardust is destined for a close encounter with the comet Wild 2 in January 2004. Using a silicon_based substance called aerogel, Stardust will capture comet particles flying off the nucleus of the comet. The spacecraft also will bring back samples of interstellar dust. These materials consist of ancient pre_solar interstellar grains and other remnants left over from the formation of the solar system. Scientists expect their analysis to provide important insights into the evolution of the sun and planets and possibly into the origin of life itself. The collected samples will return to Earth in a sample return capsule to be jettisoned as Stardust swings by Earth in January 2006