The first three missions of the program were planned to be: the Solar Orbiter, the Pluto and Kuiper belt reconnaissance mission Pluto Kuiper Express, and the Europa Orbiter astrobiology mission focused on Europa.
Tiga misi pertama dari program tersebut direncanakan menjadi Solar Orbiter, misi pengintaian Pluto dan Kuiper Belt Pluto Kuiper Express, dan misi astrobiologi Europa Orbiter berfokus pada Europa.