The final pick will be made in mid-2011 with blast-off to take place no later than Dec. 30, 2018, NASA said on its Web site Tuesday. The project is to cost no more than $650 million, excluding the launch vehicle.
The Venus proposal -- the Surface and Atmosphere Geochemical Explorer, or SAGE -- would send a probe to the planet's surface to measure its atmosphere, and measure the composition and mineralogy of its surface in an attempt to understand the origin of Venus and why it differs from Earth.
The asteroid proposal -- the Origins Spectral Interpretation Resource Identification Security Regolith Explorer spacecraft, or Osiris-Rex -- would send a spacecraft to an asteroid, take measurements and collect more than 2 ounces of material before returning to Earth to help scientists better understand the formation of our solar system.
The moon project -- MoonRise: Lunar South Pole-Aitken Basin Sample Return Mission -- would send a lander near the moon's south pole. It would return with about 2 pounds of materials scientists hope would provide insight into the early history of the Earth-moon system.
One of the three, selected from among eight proposals submitted, will become the third mission in NASA's New Frontiers series. The first, New Horizons, launched in 2006, and will fly by the Pluto-Charon system in 2015. The second mission, Juno, is to launch in August 2011 and orbit Jupiter.