The purpose of this book is to issue a warning that NASA’s mismanagement of the human space programs has exposes all of us on spaceship Earth to the increasing threat of an asteroid/comet impact. The technology has existed for decades to build a planetary defense system which would also provide an affordable commercial launch and deep space reusable space transportation system but NASA has steadfastly refused to even investigate these systems. Instead, NASA has wasted billions of dollars on unsafe, obsolete, and unaffordable human space programs as the letters in this book will verify. My concern is that this warning may be too late! Don A. Nelson is the coordinator for the Concerned American Aerospace Engineers. In his role as an aerospace media consultant and writer he has made numerous appearances on national and foreign television. He retired from NASA in January 1999 after 36 years with the agency. Mr. Nelson was a supporting team member for the first rendezvous in space, first manned mission to the moon, first manned lunar landing, and the first flight of the Space Shuttle. During his last 11 years at NASA, he served as a mission operations evaluator for proposed advanced space transportation projects. Mr. Nelson is a graduate of Southern Methodist University School of Engineering.