Not that I would choose to go to Purdue simply because of the astronauts it produced, but:

Neil Armstrong - first man to walk on the Moon
John Blaha - flew on Mir in 1996
Roy D. Bridges
Mark N. Brown
John H. Casper
Eugene Cernan - walked on the Moon
Roger Chaffee - killed in Apollo 1 accident
Richard O. Covey
Andrew J. Feustel
Guy S. Gardner
Virgil I. Grissom - killed in Apollo 1 accident
Gregory J. Harbaugh
Michael J. McCulley
Gary E. Payton
Jerry L. Ross - holds the US record for spacewalks
Mark L. Polansky
Loren J. Shriver
Janice E. Voss - aboard space shuttle Space Shuttle Endeavour in 2000
Charles D. Walker - aboard Space Shuttle Discovery
Mary E. Weber - aboard space shuttle Discovery in 1995
Donald E. Williams
David A. Wolf - flew on Mir in 1997