Explanation:

NASA announced it has selected four Discovery Program investigations to develop concept studies for possible new missions. Two proposals are for trips to Venus, and one each is for Jupiter’s moon Io and Neptune’s moon Triton. After the concept studies are completed in nine months, some missions ultimately may not be chosen to move forward. Final selections will be made next year.
These are:

• DAVINCI+: Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging Plus. This will analyse Venus’s atmosphere to understand how it was formed and evolved, and if it ever had an ocean.
• IVO: Io Volcano Observer is a proposal to explore Jupiter’s moon Io, which is extremely volcanically active.
• TRIDENT: This aims to explore Neptune’s icy moon, Triton.
• VERITAS: Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy will aim to map Venus’s surface to find out why Venus developed so differently from Earth.