In pictures: 20 key NASA projects in 2009

A monster year: 2009 was a critical year for NASA. The space agency saw its very existence reviewed by the United States Human Space Flight Plan Committee and it watched as its venerable space shuttle fleet ticked off five of its remaining 10 missions. But there were plenty of other projects that took center stage such as the development of the next generation heavy lift rocket, Ares, and the extension of the agency's Antarctica's sea ice monitoring program as well as its ongoing Mars operations. Here we take a look at some of the more interesting projects the space program took on in 2009.