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| Mission type | Reconnaissance |
|---|---|
| Operator | NASA/JPL |
| Mission duration | ≥1.5 years[1] |
| Spacecraft properties | |
| Launch mass | ≈3,939 kg |
| BOL mass | ≈2,000 kg[1] |
| Dry mass | ≈1,110 kg |
| Power | 290 W[1] |
| Start of mission | |
| Launch date | 2030 (suggested) |
| Rocket | Atlas V 511 or SLS |
| Uranus orbiter | |
| Orbital insertion | 2041 |
| Orbits | ≥14 (proposed)[1] |
OCEANUS (Origins and Composition of the Exoplanet Analog Uranus System) is a mission concept conceived in 2016 and presented in 2017 as a potential future contestant as a New Frontiers program mission to the planet Uranus.[2][1] The concept was developed in a different form by the astronautical engineering students of Purdue University during the 2017 NASA/JPL Planetary Science Summer School.[3] OCEANUS is an orbiter, which would enable a detailed study of the structure of the planet's magnetosphere and interior structure that would not be possible with a flyby mission.[2]
Because of the required technology development and planetary orbital dynamics, the concept suggests a launch in August 2030 on an Atlas V 511 rocket and entering Uranus's orbit in 2041.[1]

Ice giant sized planets are the most common type of planet according to Kepler data. The little data available on Uranus, an ice giant planet, come from ground-based observations and the single flyby of the Voyager 2 spacecraft, so its exact composition and structure are essentially unknown, as are its internal heat flux, and the causes of its unique magnetic fields and extreme axial tilt or obliquity,[1] making it a compelling target for exploration according to the Planetary Science Decadal Survey.[2][4] The primary science objectives of OCEANUS are to study Uranus's interior structure, magnetosphere, and the Uranian atmosphere.[1]
The required mission budget is estimated at $1.2 billion.[1] The mission concept has not been formally proposed to NASA's New Frontiers program for assessment and funding. The mission is named after Oceanus, the Greek god of the ocean; he was son of the Greek god Uranus.[5]
| Parts of this astronomy (those related to section) need to be updated. Please update this astronomy to reflect recent events or newly available information. (October 2024) |
Since Uranus is extremely distant from the Sun (20 AU), and relying on solar power is not possible past Jupiter, the orbiter is proposed to be powered by three multi-mission radioisotope thermoelectric generators (MMRTG),[2][1] a type of radioisotope thermoelectric generator. As of 2015[update], there was enough plutonium available to NASA to fuel three more MMRTG like the one used by the Curiosity rover, one of which was already committed to the Perseverance rover.[6][7] The other two have not been assigned to any specific mission or program,[7] and could be available by late 2021.[6] A second possible option for powering the spacecraft other than a plutonium powered RTG would be a small nuclear reactor powered by uranium, such as the Kilopower system in development as of 2019.
The trajectory to Uranus would require a Jupiter gravity assist, but such alignments are calculated to be rare in the 2020s and 2030s, so the launch windows will be scant and narrow.[2] To overcome this problem two Venus gravity assists (in November 2032 and August 2034) and one Earth gravity assist (October 2034) are planned along with the use of solar-electric propulsion within 1.5 AU.[1] The science phase would take place from a highly elliptical orbit and perform a minimum of 14 orbits.[1] If launching in 2030, reaching Uranus would occur 11 years later, in 2041,[1] and it would use two bipropellant engines for orbital insertion.[1]
Alternatively, the SLS rocket could be used for a shorter cruise time,[8] but it would result in a faster approach velocity, making orbit insertion more challenging, especially since the density of Uranus's atmosphere is unknown to plan for safe aerobraking.[7]

The 12.5 kg scientific payload would include instruments for a detailed study of the magnetic fields and to determine Uranus's global gravity field: [2][1]