Pat Duggins, author, "Trailblazing Mars: NASA's Next Giant Leap" (University Press of Florida, 2010), news director, Alabama Public Radio, Tuscaloosa, Ala.
Jeffrey A. Hoffman, shuttle astronaut (five flights), professor of the Practice of Aerospace Engineering, Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, Mass.
David Baker, author: "NASA Space Shuttle Owners' Workshop Manual" (Zenith Press, 2011), former editor, Aviation News, Sussex, England
Peter Schwartz, worked on shuttle mission planning, Stanford Research Institute
Chairman, Global Business Network, San Francisco, Calif.
With the last shuttle flight approaching in June, the future of manned spaceflight is uncertain. How far has space travel advanced in 30 years, and what's been accomplished? A panel of experts discusses the milestones and downfalls of the shuttle program and what comes next.