Five possible space missions have been selected by NASA to receive preliminary funding, ahead of a possible launch as early as 2020. Each of the projects, chosen as part of NASA's long-running Discovery program, will receive $3 million with which their creators can hone their designs, conduct analysis, and refine their plans. By September next year, one or two of the five missions will be chosen by the space agency for continued development, at a cost of around $500 million.

Among those selected for this stage of funding are the Near Earth Object Camera (NEOCam), which promises to discover "ten times more near-Earth objects" than have been discovered so far, and "Lucy," which aims to scout Jupiter's Trojan asteroids to learn more about the birth of our solar system. The Psyche project, too, plans to investigate smaller space rocks, flying to the metal-rich asteroid of the same — believed to be the result of a nasty collision with another planetary body — to work out how planetary cores are formed.

One or two of the missions will be selected to get $500 million

The group is rounded out by two Venus-specific missions, both with neat acronyms. The Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging project — also known as DAVINCI — wants to drop a probe through the atmosphere of the solar system's hottest planet, measuring its chemical composition during a 63-minute descent. The The Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy mission — or VERITAS — would produce detailed maps of Earth's neighbor, showing its topography, deformation over the years, and surface composition.

NASA kickstarted its Discovery scheme in 1992 to find new candidates for exploratory projects with "highly focused scientific goals." So far it has produced 12 missions, including MESSENGER, Dawn, Stardust, Genesis, GRAIL, and Deep Impact, the comet-hunting mission was pronounced dead after losing contact with the ground in 2013. The InSight lander, the fruit of another project sponsored by the program, is scheduled to touch down on Mars next year to study the planet's subterranean geology.