NOTE: Clementine and NASA missions such as the first flight in the New Millennium program (Deep Space 1) and the four selected Discovery missions (Near-Earth Asteroid Rendezvous, Mars Pathfinder, Lunar Prospector, and Stardust) display a variety of similarities and differences. However, the only areas where Clementine stands out as an extreme are in terms of its payload (the smallest) and its launch vehicle (a refurbished ICBM).

The process by which Clementine was selected and managed has many elements in common with four of the five NASA missions. Like Mars Pathfinder and NEAR, Clementine was preselected by its sponsoring agency. But Clementine's "skunkworks" management approach (intimate control by a small team with full authority and accountability for every aspect of the mission) has more in common with the principal-investigator mode adopted by the Discovery missions selected through open competition (Lunar Prospector and Stardust) than with the traditional approach adopted by NASA for the preselected Discovery missions. Deep Space 1 stands out as an interesting variant in that it is run as a traditional NASA program but was defined and selected via a hybrid process involving integrated product development teams, that is, groups of experts drawn from industry, academia, and government and charged with the task of identifying and prioritizing technologies likely to increase the capabilities and lower the life-cycle costs of future science missions.

^a Abbreviations and acronyms are defined in the glossary.