Thirty minutes later the professor stood at the window and watched the preparations for blast off. The tail gantry crane moved away from the rocket, and a siren blared forth its warning. The booster motors were started, splashing green flame into the pit and shaking the ground with their roar. The tall ship rose slowly at first, and then more rapidly as it climbed a column of green flame into the clearing sky. It grew small and disappeared. A few minutes later the ship's atomic drive came to life like a tiny new sun that was a beacon on the path to space.