Abstract :
It¿s smaller than originally hoped for, but with 42 radio antennas the Allen Telescope Array, or ATA, is the most advanced structure ever built to look for signs of extraterrestrial intelligence. Following technical delays and cost overruns that left it well short of its planned size, the array is expected to begin its mission full-time this month. It began performing radio astronomy last year but wasn¿t ready to look for artificial radio signals until now.
