Last week, Atlantis lifted off for the final space shuttle mission ever. The space shuttle program is older than I am, and to be honest, it's overdue for retirement. The Challenger and Columbia tragedies underscored how cantankerous and dangerous this method of low-Earth orbital delivery can be. The numerous delays in the final flights of Discovery and Atlantis emphasized the fragility of the aging shuttle fleet. So we should not be mourning the loss of…