On the frigid morning of January 28, 1986, the space shuttle Challenger rumbled off the launchpad at Cape Canaveral, Florida. Brilliant orange flames and clouds of smoke billowed out of the external fuel tank, lifting Challenger high into the crystal-blue sky. The mission had attracted worldwide attention. NASA was sending the first teacher, Christa McAuliffe, into space. Crowds gathered to watch the launch, and millions tuned in on television, but...