Uranus Orbiter and Probe

{{further|Exploration of Uranus}}

Voyager 2 is the only space probe to have visited the Uranus system, completing a flyby on January 24, 1986. The 2011-2022 Planetary Science Decadal Survey recommended a Flagship-class orbiter mission to an ice giant with priority behind what would become the Mars 2020 rover and the Europa Clipper.{{cite web |title=Visions and Voyages for Planetary Science in the Decade 2013–2022 |url=https://solarsystem.nasa.gov/resources/598/vision-and-voyages-for-planetary-science-in-the-decade-2013-2022/ |access-date=20 April 2021}}{{cite web |url=http://www.nasaspaceflight.com/2013/11/new-sls-options-new-large-upper-stage |title=New SLS mission options explored via new Large Upper Stage |author=Chris Gebhardt |publisher=NASASpaceFlight |date=20 November 2013}}{{cite web |last1=Hubbard, William B. |title=SDO-12345: Ice Giants Decadal Study |url=https://www.nap.edu/resource/13117/App%20G%2023_Uranus_Orbiter_and_Probe.pdf |website=National Academies Press |publisher=National Academy of Sciences |access-date=22 June 2020 |archive-url=https://web.archive.org/web/20210506092409/https://www.nap.edu/resource/13117/App%20G%2023_Uranus_Orbiter_and_Probe.pdf |archive-date=6 May 2021 |date=3 June 2010 |url-status=live}} Ice giants are now appreciated as a common type of exoplanet, precipitating the need for further study of ice giants in the Solar System.{{cite web |title=Ice Giants Pre-Decadal Survey Mission Study Report (June 2017) |url=https://www.lpi.usra.edu/NASA-academies-resources/full-report-ice-giants.pdf |access-date=13 Feb 2024}} The ice giants Uranus and Neptune were seen as unique yet equally compelling scientific targets, but a Uranus orbiter and atmospheric probe was given preference for logistical and cost reasons. A Uranus orbiter would logically follow Flagship-class orbiter missions undertaken at Jupiter and Saturn (Galileo and Cassini, respectively).

In 2017, prior to the 2023–2032 survey, a committee narrowed twenty mission concepts to three scenarios for Uranus and a fourth for Neptune.[https://www.theverge.com/2017/6/16/15810926/nasa-uranus-neptune-mission-voyager-2-spacecraft It’s time to explore Uranus and Neptune again — and here's how NASA could do it]. Loren Grush, The Verge. 16 June 2017.[http://www.planetary.org/blogs/jason-davis/2017/20170621-revisiting-ice-giants.html Revisiting the ice giants: NASA study considers Uranus and Neptune missions]. Jason Davis. The Planetary Society. 21 June 2017.[https://www.nasa.gov/feature/nasa-completes-study-of-future-ice-giant-mission-concepts NASA Completes Study of Future ‘Ice Giant’ Mission Concepts] {{Webarchive|url=https://web.archive.org/web/20200806062812/https://www.nasa.gov/feature/nasa-completes-study-of-future-ice-giant-mission-concepts/ |date=2020-08-06 }}. NASA TV. 20 June 2017. A mission to Neptune is viewed by some to be of greater scientific merit{{cite journal |title=Exploration Strategy for the Outer Planets 2023–2032: Goals and Priorities |year=2021 |doi=10.3847/25c2cfeb.1f297498 |url=https://baas.aas.org/pub/2021n4i371/release/1 |access-date=20 April 2021|last1=Moore |first1=Jeff |last2=Spilker |first2=Linda |last3=Bowman |first3=Jeff |last4=Cable |first4=Morgan |last5=Edgington |first5=Scott |last6=Hendrix |first6=Amanda |last7=Hofstadter |first7=Mark |last8=Hurford |first8=Terry |last9=Mandt |first9=Kathleen |last10=McEwen |first10=Alfred |last11=Paty |first11=Carol |last12=Quick |first12=Lynnae |last13=Rymer |first13=Abigail |last14=Sayanagi |first14=Kunio |last15=Schmidt |first15=Britney |last16=Spilker |first16=Thomas |journal=Bulletin of the AAS |volume=53 |issue=4 |page=371 |bibcode=2021BAAS...53d.371M |s2cid=214641023 |arxiv=2003.11182 |doi-access=free }} because Triton, likely a captured Kuiper belt object and ocean world, is a more compelling astrobiology target than the moons of Uranus (though Ariel and Miranda in particular are possible ocean worlds).{{cite journal |title=NASA Roadmap to Ocean Worlds |year=2019 |doi=10.1089/ast.2018.1955 |last1=Hendrix |first1=Amanda R. |last2=Hurford |first2=Terry A. |last3=Barge |first3=Laura M. |last4=Bland |first4=Michael T. |last5=Bowman |first5=Jeff S. |last6=Brinckerhoff |first6=William |last7=Buratti |first7=Bonnie J. |last8=Cable |first8=Morgan L. |last9=Castillo-Rogez |first9=Julie |last10=Collins |first10=Geoffrey C. |last11=Diniega |first11=Serina |last12=German |first12=Christopher R. |last13=Hayes |first13=Alexander G. |last14=Hoehler |first14=Tori |last15=Hosseini |first15=Sona |last16=Howett |first16=Carly J.A. |last17=McEwen |first17=Alfred S. |last18=Neish |first18=Catherine D. |last19=Neveu |first19=Marc |last20=Nordheim |first20=Tom A. |last21=Patterson |first21=G. Wesley |last22=Patthoff |first22=D. Alex |last23=Phillips |first23=Cynthia |last24=Rhoden |first24=Alyssa |last25=Schmidt |first25=Britney E. |last26=Singer |first26=Kelsi N. |last27=Soderblom |first27=Jason M. |last28=Vance |first28=Steven D. |journal=Astrobiology |volume=19 |issue=1 |pages=1–27 |pmid=30346215 |pmc=6338575 |bibcode=2019AsBio..19....1H |s2cid=53043052 |doi-access=free }} There was also a study that considered a New Frontiers-level Uranus orbiter mission concept if a Flagship-class mission to Neptune were favored.[http://www.lpi.usra.edu/decadal/opag/UranusOrbiter_v7.pdf THE CASE FOR A URANUS ORBITER], Mark Hofstadter et al. Nevertheless, again due to cost and logistical considerations including launch vehicle availability and available launch windows, the 2023–2032 Planetary Science Decadal Survey recommended the Uranus Orbiter and Probe instead of an analogous proposal for Neptune, Neptune Odyssey.

The orbiter paired with an atmospheric probe will address a variety of scientific questions across all aspects of the Uranus system:

• How does atmospheric circulation function, from interior to thermosphere, in an ice giant?
• What is the 3D atmospheric structure of the weather layer?
• When, where, and how did Uranus form, how did it evolve both thermally and spatially, including migration, and how did it acquire its retrograde obliquity?
• What is Uranus' bulk composition and its depth dependence?
• Does Uranus have discrete layers or a dilute core, and can this be tied to its formation and tilt?
• What is the true rotation rate of Uranus, does it rotate uniformly, and how deep are the winds?

• What dynamo process produces Uranus' complex magnetic field?
• What are the plasma sources & dynamics of Uranus' magnetosphere and how does it interact with the solar wind, Uranus' upper atmosphere, and satellite surfaces?

• What are the internal structures and rock-to-ice ratios of the large Uranian moons and which moons possess substantial internal heat sources or possible oceans?
• How do the compositions and properties of the Uranian moons constrain their formation and evolution?
• What geological history and processes do the surfaces record and how can they inform outer solar system impactor populations? What evidence of exogenic interactions do the surfaces display?
• What are the compositions, origins and history of the Uranian rings and inner small moons, and what processes sculpted them into their current configuration?

[[File:2021 Uranus Orbiter and Probe schematic.jpg | thumb | 220x124px | right | alt= Explanation of the components of a 7200-kg probe for Uranus |

Schematic of the 2021 concept study design for the Orbiter and Probe]]

The atmospheric probe element of this mission would study the vertical distribution of cloud-forming molecules, thermal stratification, and wind speed as a function of depth. The 2010 mission design envisioned a probe of {{cvt|127|kg}}, less than half that of the Galileo atmospheric probe. A later design study suggested results could be significantly enhanced by adding a second probe which could be as small as {{cvt|30|kg}} in mass and about {{cvt|0.5|m|inch}} in diameter.K. M. Sayanagi, R. A. Dillman, A. A. Simon, et al. " [https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170006873.pdf Small Next-generation Atmospheric Probe (SNAP) Concept]", LPI 2083 (2018): 2262. Long version of paper: Space Sci Rev, 216, 72 (June 10, 2020) [https://link.springer.com/article/10.1007/s11214-020-00686-7 Small Next-Generation Atmospheric Probe (SNAP) Concept to Enable Future Multi-Probe Missions: A Case Study for Uranus]. Retrieved June 22, 2020.

The orbiter is proposed to carry the following instruments in the baseline concept, with additional instruments possible should they prove to be within mass, power, and cost limitations:

The atmospheric probe is proposed to carry 4 scientific instruments as part of the baseline concept.

• Atmosphere of Uranus
• Exploration of Uranus
• Moons of Uranus

;Uranus mission proposals

• MUSE
• Oceanus (New Frontiers-class proposal of the 2010s)
• ODINUS
• Uranus Pathfinder (ESA M-Class proposal of the 2010s)

{{reflist}}

{{Uranus}}

{{Future spaceflights}}

Category:Missions to Uranus

Category:Proposed NASA space probes

Category:Orbiters (space probe)