A Neptune Orbiter with Probes Mission with Aerocapture Orbit Insertion

Abstract

A NEPTUNE Orbiter with Probes Mission is study case 17 of NRA-03-OSS01-VM. It is a fl agship mission to perform Cassini-level exploration of the Neptune system. Neptune is the prototypical ice giant, a planet composed largely of water, methane, ammonia, and other compounds that form ices at planetary temperatures. The ice giants Uranus and Neptune may be accretion cores of failed hydrogenand helium-rich gas giants. As the outermost giant planet, Neptune appears to lie at the dynamical limit for nebular debris from Solar System formation. The scientifi c objectives of the mission are: to bring our understanding of ice giants to a level where we can usefully compare them with gas giants both inside and outside of our Solar System; to explore Neptune’s satellite Triton, an analog for trans-Neptunian objects that are a likely source of volatiles for the inner Solar System; and to explore Neptune’s rings and magnetosphere, which are analogs for the solar nebula and for the accretion disks around other stars. There are two practical approaches to achieve orbit insertion at Neptune: nuclear electric propulsion, which is the subject of a different study, and aerocapture, which is the approach studied here. We describe science/engineering trades for all aspects of mission architecture: transportation to Neptune, orbit insertion at Neptune, delivery and support of multiple Neptune entry probes, an orbital tour in the Neptune system, a Triton lander, and communications during the orbital tour. We identify new