NASA this month greatly expanded its public prize competition program known as the Centennial Challenges. The space agency announced US$5 million worth of new competitions to develop robots, small satellites and solar-powered spacecraft. Since 2005, NASA has conducted 19 competition events in six challenge areas and awarded $4.5 million to 13 different teams. NASA challenges are managed with significant partners such as the X Prize Foundation, Northrop Grumman and others. Here we take a look at previous Challenges and the new programs to come.