Ken Davidian was the guest for this program to discuss NASA Centennial Challenges. Ken began our discussion by telling us some prize history, the origins of the NASA Centennial Challenges and the way in which the program works. Ken went through the prizes being offered, their respective supporting allied organizations. Several questions from listeners addressed the timing and dates of the prizes, what happens if a prize is not won, how does it work when the prize is extending over multiple years. By far, the most questions came in about the lunar lander contest, its allied organization X Prize Cup, and why it is only available to be won at one time during the year. Ken did talk about some of the budget process for this year and next, why the prize money is at this time set low, and why Centennial Challenges mostly appeals to the entrepreneurial business community, not the large aerospace industry. Your suggestions and comments are welcome at NASA Centennial Challenges. If you make a suggestion or contact Ken using this specific address, please put The Space Show in the subject line. Use ccideas@nasa.gov (this address goes to Ken). Ken can also be reached at kdavidian@nasa.gov.