View source for Engineering:Interstellar Probe (spacecraft)

{{Short description|Proposed NASA space probe to travel 1000 AU from the Sun}}
{{DISPLAYTITLE: ''Interstellar Probe'' (spacecraft)}}
{{Infobox spaceflight
| name              = ''Interstellar Probe''
| image             = Interstellar Probe (2020s).png
| image_caption     = Artist's rendering of the ''Interstellar Probe'' (plasma wave antennas extend far beyond portion shown)
| image_alt         = 
| mission_type      = Outer planetary, heliosphere, and interstellar medium exploration
| operator          = [[Organization:NASA|NASA]] / Johns Hopkins Applied Physics Laboratory
| website           = {{URL|https://interstellarprobe.jhuapl.edu/}}
| dry_mass          = 
| launch_mass       = {{convert|860|kg|abbr=on}}
| power             = 470 watts (at launch)
| launch_date       = 2036
| launch_rocket     = [[Astronomy:Space Launch System|Space Launch System]] Block 2
| decay_date        = 
| interplanetary    = {{Infobox spaceflight/IP
| type         = flyby
| object       = [[Astronomy:Jupiter|Jupiter]]
| distance     = ~4 000 km
| arrival_date = 2037
}}
| programme         = Flagship
}}

'''''Interstellar Probe''''' (''ISP'') is a proposed [[Organization:NASA|NASA]] [[Engineering:Space probe|space probe]] designed to explore and characterize the [[Astronomy:Heliosphere|heliosphere]] and interstellar space. The study was originally proposed in 2018 by NASA for the [[Organization:Applied Physics Laboratory|Applied Physics Laboratory]]. It would have a baseline launch between 2036 and 2041.<ref name="McNutt2021">{{cite web |last1=McNutt |first1=Ralph |last2=Paul |first2=Michael |last3=Brandt |first3=Pontus |last4=Kinnison |first4=Jim |title=Interstellar Probe: Humanity's Journey to Interstellar Space |url=https://interstellarprobe.jhuapl.edu/Interstellar-Probe-MCR.pdf |website=Interstellar Probe |publisher=Johns Hopkins Applied Physics Laboratory |access-date=23 December 2021}}</ref> The probe would launch on a direct hyperbolic trajectory to encounter [[Astronomy:Jupiter|Jupiter]] after six to seven months, after which the probe would travel at a speed of about {{convert|6-7|AU|km|abbr=off}} per year, leaving the heliosphere after only 16 years.<ref name="VOS">{{cite journal |last1=Stone |first1=Richard |title='Voyager on steroids.' Mission would probe mysterious region beyond our Solar System |journal=Science |date=28 July 2022 |doi=10.1126/science.ade1070 |url=https://www.science.org/content/article/voyager-steroids-mission-probe-mysterious-region-beyond-solar-system |access-date=15 August 2022 |language=en}}</ref>

The probe may have the opportunity to encounter minor planets on the way out, including Orcus and [[Astronomy:50000 Quaoar|Quaoar]], though such flybys would require specific launch dates. With next-generation radioisotope thermoelectric generators (RTGs), the mission would be designed to last for over 50 years after its launch, a similar feat reached by the ''[[Astronomy:Voyager 1|Voyager 1]]'' and ''[[Astronomy:Voyager 2|2]]'' probes despite their intended 5-year lifetime. The mission has been called "''Voyager'' on steroids".<ref name="VOS"/>

==Mission background==

Interstellar probes such as the [[Astronomy:Voyager program|Voyager program]] were made only with the intent to visit the outer planets, with the added interstellar mission as a mere bonus. Their lifetime had never been expected to be much longer than 12 years at the most, but the probes have lasted for upwards of four decades thus far. Both ''Voyagers'' left the heliosphere in the 2010s; ''Voyager 1'' in 2012,<ref>{{cite web |url=https://voyager.jpl.nasa.gov/mission/interstellar-mission/ |publisher=NASA [[Organization:Jet Propulsion Laboratory|Jet Propulsion Laboratory]] |title=Interstellar Mission |access-date=August 24, 2020}}</ref> and ''2'' in 2018.<ref name="EA-20191104">{{cite news |author=[[Organization:University of Iowa|University of Iowa]] |title=Voyager 2 reaches interstellar space – Iowa-led instrument detects plasma density jump, confirming spacecraft has entered the realm of the stars |url=https://www.eurekalert.org/pub_releases/2019-11/uoi-v2r103119.php |date=November 4, 2019 |work=EurekAlert! |access-date=November 4, 2019 }}</ref>

While their readings have been valuable, many of their instruments have been shut off due to a lack of power in their RTGs. In addition, neither of them are headed toward the IBEX ribbon, a region discovered by the [[Astronomy:Interstellar Boundary Explorer|Interstellar Boundary Explorer]] where energetic neutral atoms (ENAs) seem to highly affect the heliosphere and are able to breach it at unprecedented rates.<ref>{{cite news|url=http://www.astronomynow.com/news/n0910/15IBEX/|title=IBEX maps edge of Solar System|publisher=Astronomy Now|first=Emily|last=Baldwin|date=October 15, 2009|access-date=August 14, 2016|archive-date=September 21, 2016|archive-url=https://web.archive.org/web/20160921042935/http://astronomynow.com/news/n0910/15IBEX/|url-status=dead}}</ref>

[[File:Interstellar IBEX ribbon and dwarf planets.png|thumb|A graph displaying the IBEX ribbon juxtaposed with flyby speed and secondary targets]]

===Primary science goals===

The main goals of the ''Interstellar'' mission include characterizing the heliosphere as a habitable astrosphere by its global nature, its interactions with the Sun and the interstellar medium, and the nature of said interstellar medium. Similar goals may include viewing the Sun as a habitable exoplanetary system from beyond, with potential outbound giant or dwarf planet flybys along the way depending on chosen launch date, and understanding the universe from beyond the heliosphere.<ref name="McNutt2021"/>

==Scientific instruments==

The probe would contain two differing scientific payloads, both weighing about {{convert|85-90|kg|abbr=on}}. One would prioritize [[Physics:Lyman-alpha|Lyman-alpha]] science, whereas the other would prioritize visible and infrared imaging of flyby targets.<ref name="McNutt2021"/> Payloads highlighted in red are exclusive to the baseline payload. Instruments in green are intended for the augmented flyby payload.

{| class="wikitable" 
|-
! Instrument (abbr.)
! Dimension, range, resolution
! Heritage
|-
| [[Physics:Magnetometer|Magnetometer]] (MAG)
|[[Physics:Electromagnetic radiation|Electromagnetic radiation]]:<br />0.01–100 nT
| Magnetospheric Multiscale: DFG
|-
| Plasma Waves (PWS)
| Plasma wave observations:<br />~1&nbsp;Hz – 5&nbsp;MHz, ≤0.7 µV/m at 3&nbsp;kHz, ∆f/f ≤ 4%, ≤60 s full spectrum
| Van Allen: EFW
|-
| Plasma Subsystem (PLS)
| Ion spectrometer:<br />< 3 eV/e to 20 keV/e
| [[Astronomy:Parker Solar Probe|Parker Solar Probe]]: [[Astronomy:SWEAP|SWEAP]], Span-A
|-
| Pick-Up Ions (PUI)
| Ion counter: 0.5–78 keV/e
| ''[[Engineering:Ulysses (spacecraft)|Ulysses]]'': SWICS
|-
| Energetic Particles (EPS)
| Ionization analysis: 20 keV – 20 MeV
| Parker Solar Probe: [[Astronomy:Integrated Science Investigation of the Sun|IS☉IS]], EPI-Lo
|-
| Cosmic Rays (CRS)
| Cosmic ray analysis: H to Sn; 10 MeV/nuc – 1 GeV/nuc
| Parker Solar Probe: IS☉IS, EPI-Hi
|-
| Interstellar Dust Analyzer (IDA)
| Dust analysis: {{val|e=−19}} to {{val|e=−14}} g
| [[Astronomy:Interstellar Mapping and Acceleration Probe|Interstellar Mapping and Acceleration Probe]]: IDEX
|-
| Neutral Mass Spectrometer (NMS)
| H, {{SimpleNuclide|Helium|3}}, {{SimpleNuclide|Helium}}, {{SimpleNuclide|Nitrogen}}, {{SimpleNuclide|Oxygen}}, {{SimpleNuclide|Neon}}, {{SimpleNuclide|Neon|22}}, {{SimpleNuclide|Argon|36}}, {{SimpleNuclide|Argon|38}}, m/Δm ≥ 100 
| [[Astronomy:Jupiter Icy Moons Explorer|Jupiter Icy Moons Explorer]]: NMS
|-
| Energetic Neutral Atom Imager (ENA)
| Images emission of energetic neutral atoms; ~1–100 keV H
| Interstellar Mapping and Acceleration Probe: IMAP-Ultra
|- style="background:#FB9898;"
| Lyman-Alpha Spectrograph (LYA)
| Mapping solar wind interactions with interstellar medium:<br> ±100&nbsp;km/s Doppler range, <10&nbsp;km/s resolution
| [[Astronomy:MAVEN|MAVEN]]: IUVS
|- style="background:#98FB98;"
| Visible-Near-IR (VIR)
| Flyby imaging:<br />0.4–4&nbsp;µm; ≥ 5 ch. ≤0.975&nbsp;µm<br> >240 ch. >0.975&nbsp;µm 
| ''[[Astronomy:New Horizons|New Horizons]]'': Ralph
|- style="background:#98FB98;"
| Visible-IR Mapper (IRM)
| Infrared mapping:<br />0.5–15&nbsp;µm<br>30–100&nbsp;µm
| ''[[Astronomy:New Horizons|New Horizons]]'': LEISA, CIBER-2
|}

==Mission operations==
[[File:Interstellar (2020) baseline trajectory.png|thumb|The baseline trajectory, using a passive gravity assist at Jupiter]]
[[File:Interstellar Solar Oberth.png|thumb|The Solar Oberth trajectory, using a brake at Jupiter for a burn at perihelion]]

===Launch and trajectories===

The baseline launch would be in 2036 using a [[Astronomy:Space Launch System|Space Launch System]] in its Block 2 configuration, featuring an additional [[Engineering:Centaur (rocket stage)|Centaur]] and [[Astronomy:Star 48|Star 48]]BV booster. This launch would put the probe on a direct trajectory to Jupiter, and after a mere seven months the probe would make a gravity assist to speed out at about 95&nbsp;km/s (about 216000&nbsp;mph).<ref name="McNutt2021"/> Alternative trajectories include bringing the Star 48 booster for a burn upon closest approach; one trajectory involving that burn at Jupiter with a slightly longer transit time, and another with about the same transit time, but passing ahead of Jupiter for a dive down near the Sun for an even faster escape trajectory.<ref name="McNutt2021"/>

Further trajectory options have been considered, including performing flybys of [[Astronomy:Saturn|Saturn]], [[Astronomy:Uranus|Uranus]], or [[Astronomy:Neptune|Neptune]] depending on launch date to help characterize planetary formation and complement missing data sets, and dwarf planets to help characterize them as ''[[Astronomy:New Horizons|New Horizons]]'' did in 2015 with its flyby of [[Astronomy:Pluto|Pluto]].<ref name="McNutt2021"/>

==See also==

* ''[[Engineering:Shensuo (spacecraft)|Shensuo]]'', a proposed pair of probes by China made to explore the outer solar system and heliosphere.
* ''[[Astronomy:New Horizons|New Horizons]]'', a [[Astronomy:Pluto|Pluto]] flyby mission by NASA currently en route to explore the interstellar medium.

==References==

{{reflist}}

{{NASA}}
{{Jupiter spacecraft}}
{{Solar System probes}}
{{Asteroid spacecraft}}

[[Category:NASA space probes]]
[[Category:Proposed space probes]]
[[Category:Missions to Jupiter]]
[[Category:Missions to minor planets]]

{{Sourceattribution|Interstellar Probe (spacecraft)}}