-ODYSSEY: NASA Mission to the Neptune- System

Abigail Rymer, Principal Investigator Johns Hopkins Applied Physics Laboratory

Team includes: Kirby Runyon, Project Scientist Brenda Clyde, Project Engineer Co-Is and collaborators from 17 national and international institutions Team Structure and Philosophy

• Proposal team structure Deliberate planning for multi-generational mission and distributed leadership o See ‘Human Factors for Long Duration Missions’ by David Reinecke (White Paper to the Decadal Survey) Unabashedly Flagship. Cassini-like mission to the Neptune system. Arranged across 5 Working Groups: o and – Led by Ian Cohan and Frank Crary o Triton - Led by Lynnae Quick and Alan Stern . . Orbiter o Satellites and Rings – Led by Tracy Becker and Matt Hedman o Neptune – Led by Krista Soderlund, Kunio Sayanagi and Mark Hofstatder o – Led by Jonathan Fortney

See LPSC presentation recording at: https://www.youtube.com/watch?v=1NrYIVNvqLI

5/26/20 2 Neptune and in the Planetary Decadal Survey

“Top and only priority for a new flagship mission is the Uranus Orbiter and Probe.” [Vision and Voyages for Planetary in the Decade 2013-2022]

" A comprehensive mission to study one of the ice giants offers enormous potential for new discoveries. The committee investigated missions to both Uranus and Neptune and determined that the two systems offered equally rich science return. The Uranus mission is preferred for the decade 2013‐2022 both because of the more difficult requirements of achieving Neptune orbit and because of the availability of favorable Uranus trajectories in the coming decade.”

5/26/20 3 Voyager – the first and only mission to Neptune

• Voyager flew by Neptune in 1989

Voyager discovered • Amazing storms in Neptune’s • Unique geology on its large Triton • A tilted offset magnetosphere • Ring arcs

3/15/20 4 Is Triton an ?

• Voyager passed Triton at a distance of ~40,000 km and discovered a moon like no others in the

• Triton’s sparsely cratered surface shows evidence for geologically-recent resurfacing

• Triton’s tenuous nitrogen atmosphere and surface ices respond to seasons – it was extreme southern spring at the time of the Voyager

3/15/20 5 Mahilani Plume Triton’s Plumes

• 4 active plumes imaged by Voyager

• 8 km high

• 120 fans on surface probably from no- longer-active plumes

• Fans only seen in southern hemisphere

Are the plumes driven by solar energy? Or are they endogenic? What volatile

3/15/20 reservoir are they sampling? 6 Triton is a dwarf captured into Neptune orbit. And the Kuiper Belt dwarf are as diverse as the terrestrial planets. 7 Neptune’s Magnetosphere – Investigating the effects of a captured KBO

How is plasma sourced and transported in Neptune’s magnetosphere?

How does Neptune shed any additional mass coming from Triton’s geysers? Credit: Universal Images Group via Getty Images

How does Triton shape Neptune’s radiation belts? Credit: Mauk & Fox, JGR, 2010

Credit: NASA/GSFC/SVS

5/26/20 8 “Neptune’s were normal until Triton came crashing in.” —New Scientist

5/26/20 9 Triton’s Young Surface

• Triton’s surface age may be <10 MY (Schenk and Zahnle, 2007) Cryovolcanism? Bizarre tectonics? Heating from capture 4BY ago not adequate to explain current surface youth; Recent capture is unlikely • Obliquity tides could supply necessary energy for surface processes that would erase craters (Nimmo & Spencer, 2015) Convecting ice shell 100 – 300 km thick

Could result in 240K layer, warm enough for liquid NH3-H2O 3/15/20 10 Why is the Neptunian ring-moon system so bizarre???

• How did the Neptunian ring-moon system form?  Primordial?  Recently formed from a disruption?  How did the Triton capture impact the ring-moon system? • The dynamic Neptunian ring-moon system  Ring arcs: changing on timescales of years, and we’ve seen some disappear!  How are the rings confined? How do they evolve? • So much left to uncover…  Still discovering Neptune’s satellites!  Where are the source bodies that maintain these rings?  What are the rings & satellites made of? A link to the Kuiper Belt?

Image Assembly & Processing: Rolf Wahl Olsen 5/26/20 Image Data: NASA/JPL (, NASA Planetary11 Dt S t ) Neptune’s Magnetosphere – Investigating the effects of a captured KBO

How is plasma sourced and transported in Neptune’s magnetosphere?

How does Neptune shed any additional mass coming from Triton’s geysers? Credit: Universal Images Group via Getty Images

How does Triton shape Neptune’s radiation belts? Credit: Mauk & Fox, JGR, 2010

Credit: NASA/GSFC/SVS

5/26/20 12 Laboratory to Understand Planetary Processes Studying Neptune will test our understanding of planetary processes under extreme physical conditions

Neptune as an Archetype

Credit: NASA/Ames Research Center/Jessie Dotson and Wendy Stenzel

Voyager 2 image of High‐Speed Winds Multipolar and non‐ Massive Storms axial magnetic fields

Complex Circulation Audio continues onto this slide on Neptune science. Neptune’s Origin, Evolution, and Structure What is an ? How do they form?

Internal Structure Bulk Composition

Helled et al., 2020

Global Energy Balance

Mousis et al., 2018

Hofstadter et al., 2017

5/26/20 14 The mission

• We named it Odyssey and have taken to referring to the SC as “Ody”

• flybys help but we decided to provide direct to Jupiter options enable yearly launch opportunities. The launch window to include a Jupiter flyby would enable either about *2 payload or (more likely) the option to remove the rocket upper stage.

• It’s a nuclear mission, and we need to make sure that NASA continues our efforts to produce Pu. Increased production would be a boon for this mission and others.

5/26/20 15 Launch Vehicle Decision Path

SLSB2+kickstage (chemical direct to Neptune)  Enables annual opportunities (no Jupiter )  All chemical propulsion mission  Slowest arrival at Neptune (lowest propulsive needs) . Requires SLS Block 2 + Kickstage. . If it can’t close on mass, we are maxed on launch vehicle

Enabled option Recommended for Direct to Neptune All chemical + Jupiter GA future study Annual opportunities + SEP

SLSB2 no kickstage (chemical with JGA) Non‐SLS+SEP (chemical with 2 EGAs)  All chemical propulsion mission  Enables annual opportunities (no Jupiter gravity assist)  Slowest arrival at Neptune (lowest propulsive needs)  Requires an SEP kickstage  Might close on SLS Block 2  Analysis during the proposal demonstrates it is possible to . Jupiter is only in phase 3‐4 years, then gone for 10 eliminate SLS Block 2 (as long as we add SEP and come in faster) *Carrying the cost + complexity of SEP system . Faster arrival at Neptune . More chem. propulsive needs (larger NOI burn) . Stresses probe design more EEEN = Launch from Earth + 2 Earth flybys EJN = Launch from Earth with JG Direct and JGA Chemical SLS Options with TOF ≤ 16 yrs

SLSb2 Earth‐Neptune Direct +upperstage SLSb2 Earth‐Jupiter‐Neptune (kg)

Orbit

Neptune

to

Mass

5/26/20 Launch Year 17 Direct and JGA Chemical SLS Options with TOF ≤ 16 yrs

SLSb2 Earth‐Neptune Direct +upperstage Point SLSb2 Earth‐Jupiter‐Neptune design (kg)

Orbit

Current Dry Neptune

Mass to

Maximum Possible Mass Value

5/26/20 Launch Year 18 Spacecraft Trajectory and Arrival

Approach DM Link NOI Coast PRM Tour

Probe Cruise SEP Coast Entry 30 days The tour

Sun Rn

(1RN~24,800)km

5/26/20 Rn (1RN~24,800)km 20 Cross Divisional Opportunities

• A 16-year cruise phase out to 30-AU - Heliophysics • observations of the Solar System - • Asteroid/ Flybys – Planetary Physics

5/26/20 21 Orbiter Configuration

HGA, 4m

Dipole Antenna

NG RTS (3X) MAG Boom Probe

1# Thruster Cluster (4X) 100# Thruster (2X) 22 15 Instruments on Orbiter (Heritage)

Ion & Neutral Mass Narrow‐Angle Camera IR Mapping Radiometer Spectrometer UV Imaging (NH LORRI) (LRO Diviner) Spectrometer Vis‐IR Imaging (Cassini INMS) (NH Alice) Spectrometer (Lucy )

Laser Altimeter Plasma Detector Energetic Particles ENA Imager (Messenger MLA) Radio & Plasma ( JADE‐I) (PSP EPI‐LO) (IMAP Ultra) (Juno Waves)

Camera Dust Analyzer MAG Boom Microwave Radiometer (Juno MWR) Juno‐Cam (IMAP IDEX) 23 Probe Instruments: 7 Total, probe mass ~220kg

Inlet

Mass Spectrometer Helium Atmospheric Nephelometer Abundance Structure Detector Instrument

Ortho‐Para Instrument Net Flux Radiometer EPO Cam Get involved

• White papers: https://www.lpi.usra.edu/decadal_whitepaper_proposals/#gp Can be found via the OPAG website - or start advocating for science you want to see in this diverse system • Suggest additions to our “” tracklist on Spotify https://open.spotify.com/playlist/1Wcyce8KEX0QZvePIr0iC7?si=Qf1pvyE1Tt2814fIxaCI mA • Email me: [email protected]

5/26/20 25 ‘Neptune‐Triton: A Flagship For Everyone’

5/26/20 26 BACK UP

5/26/20 27 Spacecraft - Volume

4.56m 6.96m Dia.

D1666 Payload Adapter Falcon Fairing, 4.6m ID

31 August 2020 28 Propulsion Components Thrusters

I lb x 16

Fuel Tank Oxidizer Tank Pressurant Tank Is: 76391.58 in3 Is: 36874.52 in3 Is: 11137.78 in3 I00 lb x 2 Was: 68043.7 in3 Was: 31435.2 in3 Was: 9782.9 in^3

(Volume info from Seth Kijewski on 6/3/20)

31 August 2020 29 Propulsion Components Configuration

ISO View Bottom View

31 August 2020 30 Instruments Configuration

JADE‐I Laser JADE‐E Altimeter (3 pairs)

Diviner EPO CAM L’Ralph Epi‐Lo Alice IDEX LORRI

Mass Microwave Spectrometer Radiometer (INMS) WAVES

Ultra

31 August 2020 31 MAG Boom Length ~= 2X Orbiter Height

Boom Length = 10.5 meter

31 August 2020 32 FOV ISO View

31 August 2020 33 Gimbaled Instruments

L’Ralph Diviner +/‐ 90˚

+/‐ 30˚

Alice LORRI +/‐ 30˚

One‐axis Gimbal Biaxial Gimbals

31 August 2020 34 Sensor

Sun sensor (4X)

31 August 2020 35