NASA has announced the guest speakers who will help set the tone for the upcoming Centennial Challenges workshop on June 15/16. The purpose of this workshop will be to define space-related goals which individuals and groups could complete to win prizes - similar to the Ansari X-Prize, which awards $10 million for the first private suborbital spacecraft. The featured speakers are Senator Sam Brownback, R-Kan., Chairman, Commerce Subcommittee on Science, Technology, and Space, Dr. John H. Marburger III, Director, White House Office of Science and Technology Policy, Edward C. "Pete" Aldridge, Chairman, President's Commission on Moon, Mars and Beyond and Elon Musk, CEO and CTO, Space Exploration Technologies Corporation.