Trident is a space mission concept to the outer planets proposed in 2019 to NASA's Discovery Program.

The mission concept is supported by NASA's Ocean Worlds Exploration Program and it is intended to help answer some of the questions generated by Voyager 2's flyby in 1989.

[8] Trident takes advantage of an efficient gravity assist alignment of Jupiter and Neptune (that occurs once every 13 years) to capitalize on a narrow observational window that enables assessment of changes in Triton's plume activity and surface characteristics since the previous encounter of Neptune-Triton by Voyager 2 in 1989.

[3][9] With the advances of high-resolution imaging and a unique orbital configuration of Triton in 2038, Trident would be able to obtain a near-complete map of Neptune's moon during its sole flyby.

Trident would pass through Triton's thin atmosphere, within 500 km (310 mi) of the surface, sampling its ionosphere with a plasma spectrometer and perform magnetic induction measurements to assess the potential existence of an internal ocean.