Published February 27, 2026 | Version Published
Journal Article Open

The High-Energy Ion Telescope (HIT) for the Interstellar Mapping And Acceleration Probe (IMAP) Mission

  • 1. ROR icon Goddard Space Flight Center
  • 2. ROR icon Catholic University of America
  • 3. ROR icon California Institute of Technology
  • 4. ROR icon Kennedy Space Center
  • 5. ROR icon Johns Hopkins University Applied Physics Laboratory
  • 6. Aerodyne, 32920, Cape Canaveral, FL, USA
  • 7. ROR icon Princeton University
  • 8. Nolan Engineering LLC, 20771, Greenbelt, MD, USA
  • 9. Axient LLC, 21045, Columbia, MD, USA
  • 10. ROR icon Science Systems and Applications (United States)
  • 11. Peraton, 20770, Greenbelt, MD, USA
  • 12. ROR icon University of New Hampshire
  • 13. KBR Wyle, 20653, Lexington Park, MD, USA
  • 14. ROR icon Columbus Technologies and Services (United States)

Abstract

The Interstellar Mapping and Acceleration Probe (IMAP; McComas et al. in Space Sci Rev 214:116, 2018a; McComas et al. in Space Sci Rev 221:100, 2025) is a NASA mission designed to study two of the most important issues in heliophysics: the interaction of the solar wind with the local interstellar medium and the acceleration of energetic particles. These two puzzles are surprisingly intertwined because particle acceleration in the inner heliosphere plays a large role in the interactions at the edge of the heliosphere. The ten instruments on IMAP, situated near the Earth-Sun L1 Lagrange point, include both in situ and remote-sensing observations and are designed to work together to explore these questions. The High-energy Ion Telescope (HIT), described herein, measures in situ ions from hydrogen through nickel at energies ranging from a few MeV/nucleon to some tens of MeV/nucleon, depending upon species. While the primary focus of HIT is Solar Energetic Particles (SEPs), HIT is also sensitive to Anomalous Cosmic Rays (ACRs) and Galactic Cosmic Rays (GCRs) that are also present at these energies. Working with the other IMAP instruments, HIT studies how the variation in SEP intensities, spectra, anisotropies, and composition inform the acceleration processes that generate these particles, and, in turn, how these high-energy particles affect the outer heliosphere. This paper details the design and operation of the HIT instrument.

Copyright and License (English)

© 2026, This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

Funding (English)

This work is supported by the IMAP mission as part of NASA’s Solar Terrestrial Probes (STP) mission line (80GSFC19C0027). A.B. acknowledges support from NASA under award 80GSFC24M0006.

Conflict of Interest

C.M.S.C acknowledges membership on the Space Science Reviews editorial board. The other authors have no conflicts of interest to declare that are relevant to the content of this article.

Files

s11214-026-01279-6.pdf

Files (5.7 MB)

Name Size
md5:a436c0d7ca197ce04653c3e4801cc09b
5.7 MB Preview Download

Additional details

Related works

Describes
Journal Article: https://rdcu.be/e7U10 (URL)

Funding

National Aeronautics and Space Administration
Solar Terrestrial Probes (STP) 80GSFC19C0027
National Aeronautics and Space Administration
80GSFC24M0006

Dates

Available
2026-02-27
Version of record