Challenger, Columbia Tragedies A Reminder Not to Send Humans to Space, Says Former NASA Historian

NASA plans to send astronauts to the moon in the next few years, as well as to Mars in the late 2030s or early 2040s.

But with the looming anniversaries of the Challenger (Jan. 28, 1986) and Columbia (Feb. 1, 2003) tragedies,Alex Roland, a retired Duke