Key facts
- What: NASA’s Interstellar Mapping and Acceleration Probe (IMAP) will map the boundary of the heliosphere (the Sun’s protective bubble) and probe how particles are accelerated in space. NASA Science
- Launch (NET): 7:32 a.m. EDT on Sept. 23, 2025, aboard a SpaceX Falcon 9 from LC‑39A, Kennedy Space Center (Florida). NASA Science
- Rideshare: Launching with NASA’s Carruthers Geocorona Observatory (CGO) and NOAA’s Space Weather Follow On–L1 (SWFO‑L1). NASA
- Destination: Sun–Earth L1, ~1 million miles sunward of Earth; ~108 days cruise to L1. NASA Science Assets
- Prime mission: 2 years (with a comprehensive 10‑instrument payload); spacecraft mass ~900 kg (1,984 lb); ~2.4 m diameter. NASA Science Assets
- Spin & orbit: Spin‑stabilized at ~4 rpm in a Lissajous/halo orbit around L1 for continuous, Sun‑pointed sampling. SpringerLink
- Space‑weather value: IMAP’s I‑ALiRT (IMAP Active Link for Real‑Time) will beam near‑real‑time data that can give ~30 minutes of warning for harmful radiation. NASA Science
- Leadership & build: Mission led by PI David J. McComas (Princeton); spacecraft built and operated by Johns Hopkins APL; 27 partner institutions across six countries. NASA
- Status (Sept. 14, 2025): Integration complete; spacecraft moved for fueling in August 2025; launch targeted no earlier than Sept. 23. NASA Science
- Why it matters: Better maps of our solar system’s “force field,” sharper models of radiation hazards for missions like Artemis, and new insight into how our galactic neighborhood shapes space near Earth. NASA Science
The mission in one line
IMAP is a heliophysics mission designed to create the most detailed global maps yet of the heliosphere’s boundary and to unravel how particles get accelerated throughout the Sun’s domain. NASA Science
What IMAP will actually do
At the edge of the heliosphere—6–9 billion miles from the Sun—charged particles and magnetic fields clash with the local interstellar medium. IMAP will remotely “image” this boundary by detecting energetic neutral atoms (ENAs) that shoot straight from distant plasma regions to the spacecraft at L1. Because ENAs aren’t steered by magnetic fields, scientists can trace them back to their sources and reconstruct a global picture of the boundary’s shape, pressure, and motion. NASA Science
Beyond mapping, IMAP will connect the dots between particle acceleration near the Sun (which affects astronauts and satellites) and changes way out at the heliosphere’s edge, tying together processes across astronomical scales. NASA Science
Payload: the 10 instruments (and what they measure)
IMAP carries ten instruments spanning particles, fields, dust, and ultraviolet light. Together they cover many orders of magnitude in energy and provide overlapping, cross‑calibrated views:
- IMAP‑Lo, IMAP‑Hi, IMAP‑Ultra — three ENA imagers mapping different energy bands of neutral atoms from the heliosphere’s boundary. NASA Science
- SWAPI (Solar Wind and Pickup Ion) — samples ions from the solar wind and interstellar pickup ions. NASA Science Assets
- SWE (Solar Wind Electrons) — measures 3D distributions of solar‑wind electrons. NASA Science Assets
- CoDICE (Compact Dual Ion Composition Experiment) — determines mass and charge of solar‑wind and interstellar ions. NASA Science Assets
- HIT (High‑energy Ion Telescope) — characterizes high‑energy ions from the Sun and deep space. NASA Science Assets
- MAG (Magnetometer) — tracks the interplanetary magnetic field near the spacecraft. NASA Science Assets
- IDEX (Interstellar Dust Experiment) — samples and analyzes interstellar and interplanetary dust grains. NASA Science Assets
- GLOWS (GLObal solar Wind Structure photometer) — observes ultraviolet glow tied to solar‑wind hydrogen, revealing global solar‑wind structure over time. NASA Science Assets
Who built what (examples): IMAP‑Ultra at JHU Applied Physics Lab; HIT at NASA Goddard; MAG by Imperial College London—a snapshot of the international spread of hardware on the observatory. NASA Science
Design & operations: small spinner, big sky
IMAP is a spin‑stabilized spacecraft rotating at ~4 revolutions per minute so its sensors can sweep large swaths of sky each spin while keeping its solar arrays Sun‑pointed. From a halo/Lissajous orbit around L1, it will continuously sample the solar wind and watch the galactic “weather” pushing on the heliosphere. SpringerLink
Fast facts: ~900 kg spacecraft; ~2.4 m across; ~108 days to reach L1; 2‑year prime mission. NASA Science Assets
Space‑weather payoff (why Artemis cares)
IMAP’s I‑ALiRT pipeline will broadcast a portion of its measurements in near real time, improving radiation storm alerts for astronauts and satellites. NASA notes that from L1, IMAP can provide about a half‑hour warning of incoming hazardous particles—crucial margin for operations near Earth and on the way to the Moon. NASA Science
As Nicky Fox, head of NASA’s Science Mission Directorate, put it during a prelaunch briefing:
“IMAP will provide warnings beginning with Artemis 2 and Artemis 3 of incoming harmful radiation storms faster than any other spacecraft has done before.” Space
Flying alongside IMAP, NOAA’s SWFO‑L1 will continuously monitor solar eruptions, while NASA’s Carruthers Geocorona Observatory images Earth’s outer exosphere—a coordinated trio to sharpen models of the Sun‑Earth system. NASA
What experts say
- David J. McComas (PI, Princeton): “IMAP is a critical new mission of exploration and discovery about the heliosphere — our home in space.” APL
- Nathan Schwadron (IMAP‑Lo lead, UNH): “We are proud to deliver an outstanding instrument to IMAP that will allow us to take the next quantum leap in understanding …” UNH
- Dennis Andrucyk (NASA, 2018 selection): “IMAP is critical to broadening our understanding of how this ‘cosmic filter’ works.” NASA
- McComas on teamwork & global scope (2025): “International collaboration such as this makes our mission even stronger.” NASA Science
All quotes are kept short and verbatim from the cited sources.
How IMAP moves the field forward (IBEX → IMAP, plus Voyager context)
IMAP builds on IBEX (which discovered the enigmatic “ribbon” of ENA emission) and extends those global maps with finer energy coverage, sensitivity, and cross‑calibrated instruments. For example, the mission aims to determine interstellar hydrogen and oxygen flow speeds to better than ~5%, improving substantially on prior IBEX‑Lo capabilities (~20%). These specifics sharpen models of how the local interstellar medium presses on the heliosphere and how that pressure changes over solar cycles. SpringerLink
Meanwhile the Voyager spacecraft provide sparse, in‑situ point measurements beyond the heliopause; IMAP complements them by remotely imaging the boundary from L1, connecting local and global views of our “solar neighborhood.” NASA Science
Team, partners, and management
IMAP is managed within NASA’s Solar Terrestrial Probes Program. Princeton University leads the science; Johns Hopkins APL built the spacecraft and will operate it; and 27 partner institutions across six countries contribute instruments and analysis. That blend of university, NASA center, industry, and international partners is deliberate—a globally distributed heliophysics observatory. NASA
Timeline & what to watch next
- Jan. 2025: All 10 instruments integrated on the spacecraft (mission‑level hardware complete). NASA Science
- Aug. 2025: Spacecraft moved for fueling and final processing at Kennedy/Florida. NASA Science
- Launch (NET): Sept. 23, 2025, 7:32 a.m. EDT → ~108 days cruise to L1 → commissioning → start of routine science & I‑ALiRT near‑real‑time streaming. NASA Science
Instrument cheat‑sheet (one‑liners)
- IMAP‑Lo: Low‑energy ENAs + interstellar neutrals (ISN).
- IMAP‑Hi: Mid‑energy ENAs from the outer heliosphere.
- IMAP‑Ultra: Highest‑energy ENAs from the boundary.
- SWAPI: Solar‑wind + pickup ions.
- SWE: Solar‑wind electrons.
- CoDICE: Ion composition (mass/charge).
- HIT: High‑energy ions (solar & cosmic).
- MAG: Interplanetary magnetic field.
- IDEX: Interstellar/interplanetary dust.
- GLOWS: Ultraviolet glow that traces global solar‑wind structure. NASA Science Assets
Sources & further reading
- NASA IMAP mission page (overview, launch details, instruments, I‑ALiRT). NASA Science
- NASA IMAP Fact Sheet (Aug. 20, 2025) (mass, size, L1 cruise time, prime mission, instrument blurbs). NASA Science Assets
- NASA media advisory (Aug. 28, 2025) (co‑manifest details, team roster). NASA
- NASA blog: fueling move (Aug. 19, 2025) and instrument integration (Jan. 16, 2025) (status). NASA Science
- NASA SVS (spin rate & L1 context). NASA Scientific Visualization Studio
- Space Science Reviews (2018) (mission design; 4 rpm; performance targets vs. IBEX). SpringerLink
- Space.com (Nicky Fox briefing quote on Artemis relevance). Space
- JHU APL (mission CDR; McComas quote). APL
- Princeton/UNH (team, instrument leadership; Schwadron quote). imap.princeton.edu
Editor’s note on dates
All dates above are stated explicitly (e.g., Sept. 23, 2025) given frequent schedule changes. Always check NASA’s mission page for the very latest target.
