Interstellar Mapping and Acceleration Probe: Difference between revisions

{{Short description|Planned NASA heliophysics mission}}

{{Use American English|date=September 2020}}

{{Use dmy dates|date=September 2020}}

| name = Interstellar Mapping and Acceleration Probe

| names_list = IMAP

| image = Interstellar Mapping and Acceleration Probe.jpg

| image_caption = Artist concept of IMAP imaging the heliospheric boundary.

| image_size = 300px

| mission_type = [[Heliosphere]] research

| operator = [[Applied Physics Laboratory]]

| COSPAR_ID =

| SATCAT =

| website = https://imap.princeton.edu/

| mission_duration = 3 years (planned)<ref name="gao-apr2020">{{cite web|url=https://www.gao.gov/assets/710/706505.pdf|title=GAO-20-405, NASA: Assessments of Major Projects|page=39|publisher=Government Accountability Office|date=29 April 2020|access-date=30 April 2020}} {{PD-notice}}</ref>

| spacecraft =

| spacecraft_type =

| manufacturer = [[Applied Physics Laboratory]]

| launch_mass =

| dry_mass =

| payload_mass =

| dimensions =

| power =

| launch_date = 1 May 2025 (planned)<ref name="May2025Launch"/>

| launch_rocket = [[Falcon 9 Block 5]]<ref>{{cite press release|url=https://www.nasa.gov/press-release/nasa-awards-launch-services-contract-for-imap-mission|title=NASA Awards Launch Services Contract for IMAP Mission|publisher=NASA|date=25 September 2020|access-date=25 September 2020}}{{PD-notice}}</ref>

| launch_site = [[Cape Canaveral Space Force Station|CCSFS]], [[Cape Canaveral Space Launch Complex 40|LC-40]]

| launch_contractor = [[SpaceX]]

| entered_service =

| orbit_reference = [[Heliocentric orbit]]

| orbit_regime = [[Halo orbit]] ([[Lagrange point|L1]])

| orbit_periapsis =

| orbit_apoapsis =

| orbit_inclination =

| orbit_period =

| apsis = gee

| instruments = 10 instruments

| programme = '''[[Solar Terrestrial Probes program]]'''

| previous_mission = [[Magnetospheric Multiscale Mission]]

| next_mission =

The '''Interstellar Mapping and Acceleration Probe''' '''(IMAP)''' is a [[heliophysics]] mission that will simultaneously investigate two important and coupled science topics in the [[heliosphere]]: the acceleration of energetic particles and interaction of the [[solar wind]] with the local [[interstellar medium]]. These science topics are coupled because particles accelerated in the inner heliosphere play crucial roles in the outer heliospheric interaction. In 2018, [[NASA]] selected a team led by [[David J. McComas]] of [[Princeton University]] to implement the mission, which is currently planned to launch in late April to late May 2025.<ref name="May2025Launch">{{cite web|url=https://blogs.nasa.gov/imap/2023/11/|title=NASA's Interstellar Mapping and Acceleration Probe Passes Key Decision Point-D|publisher=NASA|date=30 November 2023|access-date=31 March 2024}} {{PD-notice}}</ref><ref name="NASA selection">{{cite web|title=NASA Selects Mission to Study Solar Wind Boundary of Outer Solar System|url=https://www.nasa.gov/press-release/nasa-selects-mission-to-study-solar-wind-boundary-of-outer-solar-system|publisher=NASA|ref=RELEASE 18-046|date=1 June 2018 |access-date=5 June 2018}} {{PD-notice}}</ref> IMAP will be a [[Solar tracker|Sun-tracking]] [[spin-stabilized satellite]] in orbit about the [[Sun]]–[[Earth]] L1 [[Lagrange point]] with a science payload of ten instruments. IMAP will also continuously broadcast real-time in-situ data that can be used for [[space weather]] prediction.

== Science ==

The [[solar wind]] and its associated magnetic field have blown a bubble in interstellar space called the [[heliosphere]]. IMAP will study the [[Heliosphere#Termination shock|heliosphere boundary]] where the solar wind collides with material from the rest of the [[galaxy]]. Using [[Energetic neutral atom|Energetic Neutral Atoms]] (ENAs), IMAP will image this interaction region from the inner [[Solar System]]. In addition, IMAP will also directly measure the [[neutral particle]]s of the interstellar medium, because they flow through the heliosphere relatively unmodified.

IMAP's science goals are based on the four science objectives specified in the IMAP Announcement of Opportunity (from the outside in):<ref name="IMAP AO">{{cite web|title=Announcement of Opportunity for Interstellar Mapping and Acceleration Probe|url=https://nspires.nasaprs.com/external/viewrepositorydocument/cmdocumentid=584241/solicitationId=%7B3C4D5DB7-30EF-FB0F-1BB9-2CD93D189E06%7D/viewSolicitationDocument=1/IMAP%20AO%20-%20Amendment%202.pdf|publisher=NASA|ref=NNH17ZDA007O|date=1 September 2017|access-date=8 January 2019}} {{PD-notice}}</ref>

== Mission ==

=== Profile ===

After launch, the spacecraft will take several months to transit to about {{cvt|1500000|km}} away from [[Earth]] towards the [[Sun]] at what is called the first [[Lagrange point]] (L1). The spacecraft will then use on-board propulsion to insert into an approximately 10° x 5° Lissajous orbit around L1, very similar to the orbit of [[Advanced Composition Explorer]] (ACE). The baseline mission is 3 years, but all expendables are designed for a lifetime of more than 5 years.<ref name=mccomas18>{{cite journal|last=McComas|first=D.J.|title=Interstellar Mapping and Acceleration Probe (IMAP): A New NASA Mission|journal=Space Science Reviews|volume=214|issue=8|page=116|doi=10.1007/s11214-018-0550-1|bibcode=2018SSRv..214..116M|hdl=1721.1/118798|doi-access=free|date=December 2018|hdl-access=free}}</ref>

=== Spacecraft ===

IMAP is a simple spin-stabilized (~4 [[Revolutions per minute|RPM]]) spacecraft with ten instruments. Daily attitude maneuvers will be used to keep the spin axis and top deck (with solar arrays) pointed in the direction of the incoming solar wind, which is a few degrees away from the Sun. In the L1 [[Lissajous orbit]], the rear deck, with its communication antenna, approximately points at the Earth.<ref name=mccomas18/>

=== Instruments ===

[[File:IMAP spectra.png|thumb|upright=1.0|right|Particle energy spectra for ions and energetic neutral atoms (inset) at 1 AU and the corresponding particle populations and IMAP instrument ranges.]]

The ten instruments on IMAP can be grouped into three categories: 1) [[Energetic neutral atom]] detectors (IMAP-Lo, IMAP-Hi, and IMAP-Ultra); 2) Charged particle detectors (SWAPI, SWE, CoDICE, and HIT); and 3) Other coordinated measurements (MAG, IDEX, GLOWS).

Shown here (top panel) are oxygen fluences measured at 1 AU by several instruments onboard [[Advanced Composition Explorer]] (ACE) during a 3-year period, with representative particle spectra obtained for gradual and impulsive [[Solar Energetic Particles]] (SEPs), corotating interaction regions (CIRs), Anomalous [[Cosmic Rays]] (ACRs), and Galactic [[Cosmic Rays]] (GCRs), and (top

panel inset) ion fluxes in the [[Voyager 1]] direction using ''in situ'' observations from Voyager and remote ENA observations from [[Cassini–Huygens]] and [[Interstellar Boundary Explorer]] (IBEX). (Middle panel) SWAPI, CoDICE, and HIT provide comprehensive composition, energy, and angular distributions for all major [[solar wind]] species (core and halo), interstellar and inner source pick-up ions, suprathermal, energetic, and accelerated ions from SEPs, interplanetary shocks, as well as ACRs. SWE, CoDICE and HIT also provide energy and angular distributions of the solar wind ion and electron core, halo, strahl, as well as energetic and relativistic electrons up to 1 [[Electronvolt|MeV]].<ref name=mccomas18/>

==== IMAP-Lo ====

IMAP-Lo is a single-pixel neutral atom imager that gives energy and angle-resolved measurements of ISN atoms ([[Hydrogen|H]], [[Helium|He]], [[Oxygen|O]], Ne, and D) tracked over >180° in [[ecliptic]] longitude and energy resolved global maps of ENA H and O. IMAP-Lo has heritage from the IBEX-Lo on IBEX but provides much larger collection power.<ref name=mccomas18/>

==== IMAP-Hi ====

IMAP-Hi consists of two identical, single-pixel high energy ENA Imagers that measure H, He, and heavier ENAs from the outer [[heliosphere]]. Each IMAP-Hi Imager is very similar in design to the [[Interstellar Boundary Explorer|IBEX]]-Hi ENA Imager but incorporate key modifications that enable substantially improved resolution, spectral range, and collection power. The instrument also incorporates a [[time-of-flight]] (TOF) system for identification of ENA species.<ref name=mccomas18/>

==== IMAP-Ultra ====

The IMAP-Ultra instrument images the emission of ENAs produced in the heliosheath and beyond, primarily in H atoms between ~3 and 300 keV, but it is also sensitive to contributions from He and O. Ultra is nearly identical to the Jupiter Energetic Neutral Imager (JENI), in development for flight on the [[European Space Agency]]'s [[Jupiter Icy Moon Explorer]] (JUICE) mission to [[Jupiter]] and [[Ganymede (moon)|Ganymede]]. Ultra's primary differences from JENI are the use of two identical copies, one mounted perpendicular to the IMAP spin axis (Ultra90) and one mounted at 45° from the anti-sunward spin axis (Ultra45) for better sky coverage, and the use of slightly thicker, UV-filtering foils covering the back plane MCPs to reduce backgrounds associated with interstellar Lyman-α photons.<ref name=mccomas18/>

==== Solar Wind and Pick-up Ion (SWAPI) ====

The Solar Wind and Pickup Ion (SWAPI) instrument measures [[solar wind]] H⁺ and He⁺⁺ and interstellar He⁺ and H⁺ pick-up ions (PUIs). SWAPI is nearly identical to the ''[[New Horizons]]'' Solar Wind Around Pluto (SWAP) instrument. SWAPI is a simplification of SWAP, and by removal of SWAP's retarding potential analyzer, significantly increases transmission and improves sensitivity, further enhancing PUI observations.<ref name=mccomas18/>

==== Solar Wind Electron (SWE) ====

The Solar Wind Electron (SWE) instrument measures the 3D distribution of [[solar wind]] thermal and suprathermal electrons from 1 eV to 5 keV. SWE is based on the heritage [[Ulysses (spacecraft)|Ulysses]] / SWOOPS, [[Advanced Composition Explorer|ACE]]/SWEPAM and [[Genesis (spacecraft)|Genesis]]/GEM instruments, with updated electronics based on [[Van Allen Probes]]/HOPE. SWE is optimized to measure ''in situ'' solar wind electrons at L1 to provide context for the ENA measurements and perform the ''in situ'' solar wind observations necessary to understand the local structures that can affect acceleration and transport.<ref name=mccomas18/>

==== Compact Dual Ion Composition Experiment (CoDICE) ====

The Compact Dual Ion Composition Experiment (CoDICE) measures charged particles in two separate energy ranges in a compact, combined instrument. CoDICELo is an electrostatic analyzer with a [[time-of-flight]] versus energy (TOF/E) subsystem to measure the 3D velocity distribution functions (VDFs) and ionic charge state and mass composition of ~0.5–80 keV/q ions. CoDICEHi uses the common TOF/E subsystem to measure the mass composition and arrival direction of ~0.03–5 MeV/nuc ions and ~20–600 keV electrons.<ref name=mccomas18/>

==== High-energy Ion Telescope (HIT) ====

The High-energy Ion Telescope (HIT) uses silicon solid-state detectors to measure the elemental composition, energy spectra, angular distributions, and arrival times of H to Ni ions over a species-dependent energy range from ~2 to ~40 MeV/nuc. HIT, heavily based on the Low Energy Telescope (LET) on the [[STEREO satellite|Solar Terrestrial Relations Observatory (STEREO)]], delivers full-sky coverage with a large geometry factor. A portion of the HIT viewing area is also optimized to measure 0.5 - 1.0 MeV electrons.<ref name=mccomas18/>

==== Magnetometer (MAG) ====

The IMAP magnetometer (MAG) consists of a pair of identical triaxial [[Magnetometer#Fluxgate magnetometer|fluxgate magnetometers]] that measure the 3D interplanetary magnetic field. Both magnetometers are mounted on a 1.8 m boom, one on the end and the other in an intermediate position. This configuration, through gradiometry, reduces the effect of spacecraft magnetic fields on the measurements of the instrument by dynamically removing the spacecraft field. The MAG are based on the [[Magnetospheric Multiscale Mission]] magnetometers.<ref name=mccomas18/>

==== Interstellar Dust Experiment (IDEX) ====

The Interstellar Dust Experiment (IDEX) is a high-resolution dust analyzer that provides the elemental composition, speed and mass distributions of [[Cosmic dust|interstellar dust]] particles. IDEX's sensor head has a large effective target area ({{cvt|700|cm2|disp=sqbr}}), which allows it to collect a statistically significant number of dust impacts (> 100/year).<ref name=mccomas18/> This instrument was constructed at the [[Laboratory for Atmospheric and Space Physics]] (LASP) at the [[University of Colorado Boulder]].<ref name="LASPinfo">{{cite web |title=Quick Facts: Interstellar Mapping and Acceleration Probe (IMAP) |url=https://lasp.colorado.edu/home/missions-projects/quick-facts-imap/ |website=LASP |access-date=23 June 2022 |archive-date=19 June 2022 |archive-url=https://web.archive.org/web/20220619050413/https://lasp.colorado.edu/home/missions-projects/quick-facts-imap/ |url-status=dead }}</ref>

==== GLObal solar Wind Structure (GLOWS) ====

The GLObal Solar Wind Structure (GLOWS) is a non-imaging single-pixel Lyman-α photometer that will be used to observe the sky distribution of the helioglow to better understand the evolution of the solar wind structure. The helioglow is formed by the interaction between interstellar neutral hydrogen (ISN H) and solar photons in a specific ultraviolet region called the Lyman-α waveband.

Photons enter the detector through a collimator with a baffle that restricts the photons to those only from GLOWS’ field of view (FOV). A spectral filter allows only photons found in the Lyman-α wavelength band into a channel electron multiplier (CEM) detector that counts them. GLOWS’ FOV shifts with IMAP's daily spin axis redirection, allowing for sequential observations of the structure of the solar wind from separate locations around the Sun. The Lyman-α photon counts from these observations can be used to build a more comprehensive picture of the solar wind structure and how it changes through the solar cycles.

GLOWS design and assembly is led by the [[Space Research Centre of Polish Academy of Sciences|Space Research Center]], [[Polish Academy of Sciences]], Warsaw, Poland (CBK PAN).<ref>{{Cite web |title=GLOWS |url=https://glows.cbk.waw.pl/ |access-date=2023-04-10 |website=GLOWS |language=en-US}}</ref><ref>{{Cite web |title=GLOWS (Global Solar Wind Structure) |url=https://imap.princeton.edu/instruments/glows |access-date=2023-04-10 |website=Interstellar Mapping and Acceleration Probe (IMAP) mission at Princeton |language=en}}</ref>

<ref name="mccomas18" />

=== Communications ===

Nominally, IMAP will have two 4-hour contacts per week through the [[NASA Deep Space Network]] (DSN). This is sufficient to upload any commands, download the week's worth of science data and housekeeping, and perform spacecraft ranging required for navigation. DSN will communicate with the IMAP Mission Operation Center (MOC) at [[Johns Hopkins University]] [[Applied Physics Laboratory]], which will operate the spacecraft. All science and ancillary data will pass through the MOC to the Science Operations Center (SOC) at [[LASP]].<ref name=LASPinfo/> The IMAP SOC at LASP will be responsible for all aspects of instrument operations: planning, commanding, health and status monitoring, anomaly response, and sustaining engineering for the instruments. The SOC will also handle science data processing (including data calibration, validation and preliminary analysis), distribution, archiving, and maintaining the IMAP data management plan. Science data will be produced centrally using algorithms, software, and calibration data provided and managed by each instrument team.

All science and other data will be shared with the heliophysics community as rapidly as practical with an open data policy compliant with the NASA Heliophysics Science Data Management Policy. The NASA Space Physics Data Facility (SPDF) is the final archive for IMAP, with regular transfer of data to the SPDF so that the data can be made available through their Coordinated Data Analysis Web (CDAWeb) site.<ref name=mccomas18/>

=== Space weather data ===

IMAP will supply critical real-time [[space weather]] data through its "IMAP Active Link for Real-Time" or I-ALiRT. IMAP will continuously broadcast a small subset (500 bit/s) of the science data for I-ALiRT to supporting ground stations around the world when not in contact with the DSN. During DSN tracks, the flight system includes the space weather data in the full-rate science data stream, which the MOC receives from the DSN and forwards to the SOC. In either case, the SOC processes these real-time observations to create the data products required by the space weather community. Data include all of the important parameters currently provided by [[Advanced Composition Explorer]] (ACE), but at significantly higher cadence, and also include several new key parameters.<ref name=mccomas18/>

=== Management ===

This is the fifth mission in NASA's [[Solar Terrestrial Probes program]].<ref>{{cite web|url=https://science.nasa.gov/heliophysics/programs/solar-terrestrial-probes|title=Solar Terrestrial Probes |website=science.nasa.gov|publisher=NASA|access-date=5 June 2018}} {{PD-notice}}</ref> The Heliophysics Program Office at NASA's [[Goddard Space Flight Center]] in [[Greenbelt, Maryland]], manages the STP program for the agency's [[Heliophysics Science Division]] in [[Washington, D.C.]]

The mission's principal investigator is [[David J. McComas]] of [[Princeton University]]. The [[Johns Hopkins University]]'s Applied Physics Laboratory in [[Laurel, Maryland]], will provide project management.<ref name="NASA selection"/>

The mission is cost-capped at US$564 million, excluding cost for the launch on a [[SpaceX]] [[Falcon 9 Block 5|Falcon 9]] launch vehicle from [[Cape Canaveral Space Launch Complex 40]] (SLC-40) at [[Cape Canaveral Space Force Station]] (CCSFS) in [[Florida]].<ref>{{cite web|url=https://www.nasa.gov/press-release/nasa-awards-launch-services-contract-for-imap-mission|title=NASA Awards Launch Services Contract for IMAP Mission|date=25 September 2020|publisher=NASA|access-date=25 September 2020}} {{PD-notice}}</ref> As of April 2020, the preliminary total cost of the mission is estimated to be US$707.7 million to US$776.3 million.<ref name="gao-apr2020"/>

== Missions of Opportunity ==

NASA plans on including an [[EELV Secondary Payload Adapter]] (ESPA) ([[National Security Space Launch|Evolved expendable launch vehicle]]) Grande ring below the IMAP spacecraft, which will give the opportunity for 4 or 5 secondary payloads to ride along with the IMAP launch.<ref name="IMAP AO"/> Deployment of the secondary payloads will occur after IMAP deployment into a transfer orbit to the Earth-Sun L1 [[Lagrange point]]. Some of the slots may be used by other divisions in the [[Science Mission Directorate]] and some may be used by other government agencies. Two opportunities for slots were competed for the [[Heliophysics Science Division]] as part of the Third Stand Alone Missions of Opportunity Notice (SALMON-3) Program Element Appendix (PEA), with proposals for both due on 30 November 2018. Selection for Phase A studies should be announced in 2019.{{update after|2020}}

=== Science opportunity ===

The Announcement of Opportunity for the 2018 Heliophysics Science Missions of Opportunity (MoO) included the option of proposing a Small Complete Mission (SCM) to utilize the IMAP ESPA Grande to launch a secondary payload. Up to two ports on the ESPA Grande ring may be allocated for Science MoOs. The payloads are designated as [[Launch Services Program#Launch vehicle contractors (LVC)|Class D]] as defined in NPR 8705.4.<ref name="Science MO AO">{{cite web |url=https://nspires.nasaprs.com/external/viewrepositorydocument/cmdocumentid=643762/solicitationId=%7B625C8214-887D-5221-1546-F77A493430C7%7D/viewSolicitationDocument=1/PEA%20M%20HPSMO%20Amend%2010.pdf |title=Announcement of Opportunity for 2018 Heliophysics Science Mission of Opportunity|publisher=NASA|ref=NNH17ZDA004O-HPSMO|date=26 September 2017|access-date=9 January 2019}} {{PD-notice}}</ref>

=== TechDemo opportunity ===

The Announcement of Opportunity for the 2018 Heliophysics Technology Demonstration (TechDemo) Missions of Opportunity requested SCM proposals for spaceflight demonstration of innovative medium Technology Readiness Level (TRL) technologies that enable significant advances in NASA's Heliophysics Science Objectives and Goals. TechDemo investigations must be proposed for flight as a secondary payload with the IMAP mission. Up to two ports on the ESPA Grande ring may be allocated for TechDemo. The payloads are designated as Class D as defined in NPR 8705.4. Down-selection{{clarify|date=July 2021}} is targeted for the third quarter FY 2020.<ref name="Tech Demo AO">{{cite web|url=https://nspires.nasaprs.com/external/viewrepositorydocument/cmdocumentid=643723/solicitationId=%7BB39034C7-23E9-3613-F806-BFDEC43C68EE%7D/viewSolicitationDocument=1/PEA%20L%20HPD%20TechDemo%20MO_amend9.pdf |title=Announcement of Opportunity for 2018 Heliophysics Technology Demonstration Mission of Opportunity |publisher=NASA |access-date=9 January 2019}} {{PD-notice}}</ref> {{update after|2021}}

== See also ==

{{Portal|Spaceflight}}

== References ==

{{Reflist|30em}}

== External links ==

* {{Official website|https://imap.princeton.edu/}} - Official Princeton IMAP site

* [https://www.srl.caltech.edu/ACE/ ACE Home ] - Official Caltech ACE site

* [http://lasp.colorado.edu/home/missions-projects/quick-facts-imap/ IMAP Quick Facts] {{Webarchive|url=https://web.archive.org/web/20211126133248/https://lasp.colorado.edu/home/missions-projects/quick-facts-imap/ |date=26 November 2021 }} - University of Colorado, Boulder IMAP page

[[Category:2025 in spaceflight]]