Top photo: Edwin Dale Hahn takes off from the starting line in an acceleration and noise test during the Clean Snowmobile Challenge, held in late March, 2001 outside Yellowstone National Park. The UAF team of Hahn and Jason Rohwer finished with the second-quietest machine in the collegiate competition. -Jason Rohwer photo.

Bottom photo: UAF engineering students Edwin Dale Hahn, left, and Jason Rohwer pose with their entry in the Society of Automotive Engineers Clean Snowmobile Challenge, held outside Yellowstone National Park in March, 2001. -Photo courtesy of Jason Rohwer.