Ralph L. McNutt, Jr.

The John Hopkins University Applied Physics Laboratory, USA

ISSI – BJ Forum: Session 1 Introduction and Exploration of Outer Overview Heliosphere and Interstellar 9:40 AM – 10:10 AM Medium - Beijing, China Thursday 7 November 2019 Introduction and Agenda • Context: The Current Effort • History: What Interstellar Probe Is • Science: The Compelling Case - Science Goal 1: Understand our Heliosphere as a Habitable Astrosphere - Science Goal 2: Understand Formation and Evolution of Planetary Systems - Science Goal 3: Uncover Early Galaxy and Star Formation • An Example Science Traceability Matrix • Example Instruments and Example Payload(s) • Where Could We Go: Target Map • Constraints and Trade-Offs • Mission Architecture Options and Engineering Requirements • “Deeper Dive” Tasks – Engineering Ramp Up • Final Thoughts

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 2 Study Team and Collaborators • R. L. McNutt, Jr (Study Principal Investigator) • P. C . B r a ndt (Study Project Scientist) • K. E. Mandt (Deputy Study Project Scientist) • M. V. Paul (Study Manager) • E. Provornikova (Working Group Lead – Heliosphere/Local Interstellar Medium) • C. Lisse (Working Group Lead – Circum-Solar Debris Disk/Astrophysics) • K. Runyon (Working Group Lead – Kuiper Belt Objects/Planetary) • A. Rymer (Working Group Lead - Exoplanetary Connections)

And almost 200 professional scientists and engineers world-wide actively working in support for Interstellar Exploration

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 3 Status

• Contract with NASA Heliophysics Division added funding 25 July 2019 • Period of performance extended to 30 April 2022 - Allows for final report to be delivered late Fall 2021 to help inform next Heliophysics Decadal Survey • Effort comparable to pre-phase A study effort at APL 2002– 2006 on Solar Probe - Focused on engineering design and trades as informed by cross- disciplinary science community

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 4 Meetings and Presentations (Recent) • Invited talk at AOGS meeting in Singapore 1 August 2019 - Session ST05 - From the Heliosphere to Interstellar Exploration • Invited talk NASA NASA STMD/SMD Workshop 10 September 2019 - Interstellar Medium Spacecraft Technology Workshop – Washington DC • Invited talk at Horizon 2061 meeting in Toulouse 11 September 2019 • Invited talks at EPSC – DPS Joint Meeting 17 September 2019 - Session MIT6 = Interstellar Probe: science, mission designs, opportunities and challenges • Talks at 70th IAC in Washington DC 24 October 2019 - Session 4.4 Strategies for Rapid Implementation of Interstellar Missions: Precursors and Beyond • Special Session at 70th IAC in Washington DC 25 October 2019 - Interstellar Probe: Humanity's First Deliberate Step into the Galaxy by 2030 • Invited Lecture in Oak Ridge, Tennessee 28 October 2019 - Talk, tour, and update on Pu-238 production status at Oak Ridge National Laboratory

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 5 Recent Publications

Brandt et al (2019) McNutt et al (2019)

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 6 “Interstellar Probe”

• … is a mission through the outer heliosphere and to the nearby “Very Local” interstellar medium (VLISM)

• … uses today’s technology to take the first explicit step on the path of interstellar exploration (faster than the Voyagers – on an SLS or commercial equivalent)

• … can pave the way, scientifically, technically, and programmatically for more ambitious future journeys (and more ambitious science goals)

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 7 Voyager 1 at 147 AU; 20.5 light hours from Earth

To the VLISM: The Next Step

Logarithmic scale

We are here

Earth: The “pale blue dot” Planets from 40.4 AU (from Voyager 1 in 1990) 7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 8 Three “Special Probes”… One Beginning … and One To Go

Parker Solar Parker Solar Probe: Probe 12 August 2018 3:31 a.m. EDT Interstellar ✓ March 1960: The “Simpson Probe Committee”

Ulysses

Ulysses: 6 October 1990 11:47:16 UTC ✓ (STS-41 launch)

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 9 The third one: Interstellar Probe - A 59-year(+) Old Idea

• 1960: The Space Studies Board “Outer solar system probe: to be aimed away from the Sun…” • 1965: Eugene Parker advocates mission to heliospheric boundary region Deep Space Probe (1965) Jupiter Galactic Probe (1967) • 1977: Voyager-1 launch Pioneer 10/11 (1980) • 1990: The Interstellar Probe (Holzer et al., 1990) • 1999: JPL Study (NASA STDT) • 2001: NIAC Study, APL Voyager (1977) • 2005: Innovative Interstellar Explorer (McNutt et al., 2005) (“Vision Mission”) • 2009: The Interstellar Heliopause Mission (Wimmer-Schweingruber et al., New Horizons (2006) 2009) • 2015: Keck Institute of Space Studies (KISS) Report

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 10 Two Distinct Questions

• What should we do? • The question for a future Science Definition Team or equivalent and the science community overall via Decadal Surveys

• What could we do? • The question at hand for this study

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 11 The Current Study • The Johns Hopkins University Applied Physics Laboratory has been tasked by the NASA Heliophysics Division to (re-)study the mission (as of 13 June 2018)

• Provide input to help support the next round of “Decadal Surveys” in the United States - Focus on the time frame in the next Heliophysics Decadal: 2023 – 2032: Could we launch a scientifically compelling mission that decade? – technical question but not without science implications

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 12 Notional “Starting Place” • The Task at hand: A Heliophysics engineering study informed by science • But… Look for possible synergies across the other Divisions within NASA’s Science Mission Directorate • Study Name: “First Pragmatic Interstellar Probe Mission Study” • Payload Mass: Within current payload-to-S/C-mass ratios • Technology: All technology shall be ready for flight by 1 January 2030

• These study requirements needed to conduct the engineering analysis. Think of this as the “parameter space” that we have chosen deliberately to make sure this is pragmatic

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 13 The Compelling Case: Questions Span NASA Science Divisions

Heliophysics Potential for Science Goal 1: The HeliospherePlanetary as a Habitable Astrosphere expandedAs we Global Nature of the Heliospheric Interactions scienceseek acrossanswers all ofto Science Goal 2: Origin and Evolution of NASA’sthe Planetary Systems Science Properties of dwarf planets/KBOs and large-scale question structure of the circum-solar debris disk Mission Directorateof Science Goal 3: Early Formation and Evolution of GalaxiesAstrophysics and Stars habitability Uncovering the Diffuse Extragalactic Background Light

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 14 Science Goal 1: The Heliosphere as a Habitable Astrosphere

• Integral to evolution of habitable systems Mira

• Missing in the family portrait of Astrospheres BZ Cam • Dedicated measurements resolve LL Orionis the new physics uncovered by the Voyagers

IRC+10216 • The first ENA and UV images looking back uniquely determines the global nature

• Voyager, IBEX, Cassini, JUICE and IMAP guide

Zeta Ophiuchi the optimal exit

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 15 Science Goal 2: Formation and Evolution of Planetary Systems

Debris Disks: Signposts of terrestrial Dwarf Planets: Unexplored active worlds planet formation and evolution KBOs: Fossils of solar system formation and composition Eta Corvi – 1400 Myr Pluto

• IR imaging reveals our unseen circum-solar debris disk • Flyby observations provide leaps in understanding solar system Charon Fomalhaut – 440 Myr Quaoar and Weywot 400 AU formation and Kuiper Belt comparative planetology • Ground truth for exoplanetary systems and disks 2014MU69 HL Tauri - < 1 Myr 7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 16 Science Goal 3: Uncover Early Galaxy and Star Formation • Extragalactic Background Light (EBL) is all the light that has ever shined • Holds the collective knowledge of Obscured by Zodiacal Cloud early formation: (1) starlight in z =

20 z=2-5 galaxies - 2 – 5 galaxies,Z ~ 10 (2) galactic dust re-emission, and (3) the light from 100’s µm 100’s - , Z = 6 6 Z = , Dust the first stars Myr Z, ~1100 Myrs • Uncover the EBL by going beyond Reionization ~0.38 1000

- the Zodiacal Cloud, which

Diffuse EBL 1 EBL Diffuse obscures the 1-100 µm window 150 by 10 - 100x • EBL measurements provide Decadal-level cosmology science enabled by unique outside location

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 17 A “Menu” Approach

• Look widely across the science and technical communities • Assemble a “Menu” of what has been done and what can be done • By its nature this is a “superset” of what might be implemented • “Ordering” from the menu will we a charge to a future Science Definition Team – at NASA’s discretion • But one always would like the assurance about what orders can be placed – and delivered – and what they would cost • This approach has been adopted successfully in the past in providing input to the Decadal Surveys

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 18 An Example Science Traceability Matrix

Goals Questions Specific Questions Measurements Structure of Heliopause, Bowshock, H-Wall Probe boundaries in-situ and image structure in ENAs and What is the Global Structure UV, radio of the Heliosphere? Nature of heliosheath, Energy partitioning Particle distributions Acceleration at astrophysical shocks The Heliosphere as a How do the Sun and the Shock and HP response In-situ, ENA, UV, radio Habitable Astrosphere Galaxy Affect the Dynamics Extent of influence in to ISM ISM properties of the Heliosphere? Effects on inner heliosphere In-situ ISM vs solar system composition What is the Nature of the Isotopic composition Recent nucleosynthesis in the ISM Interstellar Medium? Interstellar Dust Dust composition Circum-Solar Debris Disk In-situ dust, IR 10-100 µm How did Matter in the Solar Current state of evolution, collisional processes of Origin and Evolution of KBO and dwarf planets System Originate and VISNIR imaging Planetary Systems Dynamical and compositional state of the Kuiper Belt Evolve? Sub-surface oceans and atmospheres of KBOs and VISNIR, UV, magnetic field dwarf planets The Universe Beyond the How did Galaxies Form and Diffuse Extragalactic Background Light Diffuse EBL IR spectral measurements 10-100 µm Circum-Solar Dust Cloud Evolve in the Universe?

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 19 Example Instruments and Example Payload(s)

Mass Power Data rate Spacecraft Instrument TRL Heritage (kg) (W) (bps) Requirements Vector Helium Magnetometer 1 2 6 Boom >10 m, Spinning 6 Cassini, rocket flights Fluxgate Magnetometer 5.6 2.2 1200 Boom >10 m, Spinning >7 Voyager (3.6 m boom) >10 m antennas, Plasma Wave Instrument 6 1.5 100 6 Voyager, Van Allen Probes, MMS Spinning Cosmic-ray spectrometer 3 2 2 Spinning 3 (compact) ACE Deployable cover, Ram Cassini/CDA, Europa Clipper, IMAP, Dust Detector 14 25 579 6 pointing NASA Matisse Neutral Ion Mass Spectrometer 3.5 5 1 Ram pointing 7 Bepi Colombo, Rosetta, JUICE IBEX-Lo comparison: 11.5 kg, 3.46 W, Low-Energy ENA 3 3 100 Scanning Platform 6 122 bps IBEX-Hi values shown Medium-Energy ENA 7.37 0.65 99 Spinning 9 Heritage: IBEX-Hi Cassini/INCA, IMAGE/HENA, High-Energy ENA 7.2 6.5 500 Spinning >7 JUICE/JENI, IMAP-Ultra DMSP SSUSI; NASA TIMED/GUVI; Ly-alpha Spectrograph 12.5 11.86 24 Scanning Platform 7 SSUSI-Lite 3-axis, Pushbroom VisNIR Imager 8.6 15 16 6 LORRI, DRACO, EIS heritage operations VISNIR/FIR Mapper 4 3 10 Spinning 5 Rosetta, LORRI Total 75.77 77.71 2637

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 20 The combined ion and ENA Camera JENI on board the ESA Example Instrumentation Identified JUICE and NASA IMAP missions.

The combined plasma and energetic particle sensor on board the NASA IMAP mission Dust detector. Cosmic Dust Analyzer from A dual-purpose imager (0.5-15.0 µm + 40-100 um) can Cassini target the zodiacal dust cloud, the EBL galactic and KBOs. shown. New Horizons/Ralph shown. LORRI on board New Horizons.

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 21 Where We Could Go: Target Map Positions from 2020 - 2031

“Tail” Barnard’s Star

2018 VG18 (Farout) “Nose”

WISE 0855-0714 e Eridani Heliospheric features a Centauri Outer planets

KBOs Background based on IBEX-Hi 1.11 keV combined differential flux data – Release 4

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 22 Critical Trade-Offs Are Not New • Mass: Driven by flyout speed and • Communication: Solid, near-term, tested payload capability engineering - S/C range 300-800 kg (New Horizons - Ka-band at ~640 bps and more at 140 AU 478.3 kg) and beyond P/L ~40-50 kg (New Horizons 30.4 kg) - - Optical laser comm might achieve ~10 kbps, but requires extreme pointing stability; lifetime needs investigation

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 23 Nor Are Enabling Technologies • Power: GPHS RTG – life efficiency and • Propulsion/Launch Vehicle: lifetime for use in vacuo Keys for implementation - Galileo, Cassini, Ulysses - Voyager (MHW RTG) will last to mid-2020’s - In-depth trajectory - Pu-238 production program has turned a corner analysis including accurate mechanical and thermal designs together with launch vehicle (LV) providers - Propulsion technology and engineering assessment of what works and what does not GPHS–RTG MHW–RTG MMRTG

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 24 Notional Concepts: 825 kg to 250 kg Combine with SLS Launch vehicle and kick stages, e.g. Castor 30XL

Voyager Parker Solar New Horizons Ulysses Pioneer 10 825.4 kg Probe 643.0 kg 478.3 kg 366.7 kg 251.8 kg

Current example for study

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 25 Engineering Requirements

• Engineering requirements are needed to frame the engineering study - “Bound the box” – but allow for trades - Still evolving (1) Enable a mission that can be launched no later than 1 January 2030. (2) Have the capability to operate from a maximum range of not less than (NLT) 1000 astronomical units (AU) from the Sun. (3) Require no more than 400 Watts of electrical power (We) at the beginning of mission (BOM) and be able to operate at no less than half of the BOM amount at the end of mission (EOM). (4) Achieve a mission lifetime of NLT 50 years with a probability of success of NLT 85%.

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 26 Mission Concept(s)

• Option 1: Unpowered Jupiter Gravity Assist (JGA) - Burn all stages directly after launch - Follow with optimized prograde JGA • Option 2: Active Jupiter Gravity Assist - Take one stage to Jupiter and burn it at optimized perijove - Opposite of orbit insertion maneuver • Option 3: JGA + Oberth Maneuver Near the Sun - Reverse JGA to dump angular momentum - Fall in to the Sun without actually hitting the Sun, maximizing your incoming speed - Burn final stage(s) at (close) perihelion

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 27 Option 3: Shield Estimates (Star 48BV)

• Accommodate New Horizons – like Interstellar Probe: mass and layout as a model • Options 1 and 2: Estimate performance Umbra clearance checks made for each configuration • Option 3: Estimate thermal shield for perihelia of 3 RS, Thermal 4 RS, and 5 RS analysis at - Verify thermal performance

5 Rs - Estimate thermal shield mass ~2200°C to - Estimate system performance 2600°C (hottest)

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 28 Designing for Different Perihelia: CASTOR 30XL

• Option 3 configuration with Increasing temperature, shield mass à notional New Horizons – like

spacecraft and CASTOR 30XL 5 Rs 4 Rs 3 Rs stage with thermal shields for 3

RS, 4 RS, and 5 RS perihelia

Option 3 engineering studies in progress Estimate is now > 10 AU/yr

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 29 Realities of Flight Near the Sun – Connecting with PSP…

• You can’t “go at night” - At end of Parker Solar Probe (PSP) mission (in seven years) we will be at a perihelion passage

of 9.86 Rs • Not close enough!

But PSP may be a pathfinder to solutions

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 30 Example: PSP Risk Mitigation and Study Effort

• Potential performance gains from using a Solar Oberth Maneuver look promising • Simplest notions cannot currently be built or flown • The situation is analogous to that facing Parker Solar Probe development team for TPS in 2002 https://solarprobe.gsfc.nasa.gov/SP_RMStudy_HiRes.pdf https://solarprobe.gsfc.nasa.gov/SolarProbe+ME.pdf

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 31 A Possible Mission • Mode: Option 1 • Immediate Target: Quaoar and its system • Final Target: VLISM • Launch: 2/24/2030 • Arrival: 1/28/2037 • TOF: 6.93 years • TOF to J: 9.77 months • C3: 329 km2/s2

• J-Flyby r: 5.26 RJ

• V∞/⨀: 5.97 AU/yr

• Q-Flyby V∞: 29.07 km/s • Distance @Q: 42.29 AU

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 32 24 February 2030…

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 33 24 February 2030…

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 34 The real journey has only just From the Sun to the Stars begun…

7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 35 7 November 2019 ISSI-BJ Forum on EXPLORATION OF OUTER HELIOSPHERE AND NEARBY INTERSTELLAR MEDIUM 36