Those who have given their lives in the pursuit of knowlege and exploration.

Apollo 1 Crew
Virgil I. "Gus" Grissom
Edward H. White II
Roger B. Chaffee

Challenger Crew
Francis R. Scobee
Michael J. Smith
Ronald E. McNair
Ellison S. Onizuka
Judith A. Resnick
Gregory B. Jarvis
Christa McAuliffe

and now
Columbia's Crew
Rick Husband
William McCool
Michael Anderson
Kalpana Chawla
David Brown
Laurel Clark
Ilan Ramon