NASA’s Interstellar Mapping and Acceleration Probe (IMAP) is assembling a comprehensive picture of our Sun’s protective bubble, the heliosphere, from the first Earth–Sun Lagrange point (L1), about one million miles sunward of Earth. From this vantage, IMAP is designed to track particles streaming from the boundary between the solar wind and interstellar medium while also offering roughly a half-hour alert of hazardous solar radiation for astronauts and spacecraft operating near Earth.
Why L1 matters for space weather
L1 provides a continuous, unobstructed view of the solar wind before it reaches Earth. By sampling ions, electrons, and energetic neutral atoms (ENAs) upstream, IMAP supports earlier and more detailed assessments of solar energetic particle events. This improves situational awareness for human spaceflight, satellite operations, and mission planners managing risk during heightened solar activity.
Ten-instrument payload
IMAP carries 10 coordinated instruments to map particle populations and fields from the inner heliosphere to its distant boundary:
- IMAP-Lo (University of New Hampshire): Images low-energy ENAs and samples interstellar neutral atoms entering the solar system.
- IMAP-Hi (LANL, SwRI, UNH, University of Bern): Maps medium-energy ENAs from the heliosphere’s outer regions.
- MAG (Imperial College London): Measures the interplanetary magnetic field carried by the solar wind.
- SWAPI (Princeton University): Detects solar-wind ions and pickup ions originating beyond the solar system.
- HIT (NASA Goddard): Samples high-energy ions from both the solar wind and deep-space sources.
- GLOWS (Space Research Center, Polish Academy of Sciences): Observes the ultraviolet glow of the solar wind to track its global structure and evolution.
- IMAP-Ultra (Johns Hopkins APL): Images high-energy ENAs tied to processes at the heliosphere’s edge.
- SWE (Los Alamos National Laboratory): Measures solar-wind electrons to characterize plasma conditions.
- CoDICE (Southwest Research Institute): Determines the mass and charge states of ions from interstellar space and the solar wind.
- IDEX (LASP, University of Colorado Boulder): Analyzes the composition of interstellar and interplanetary dust particles.
Mission roles and management
The mission is led by Princeton University with a team spanning 27 partner institutions. The Johns Hopkins Applied Physics Laboratory developed the spacecraft and operates the mission. NASA’s Goddard Space Flight Center oversees the program for the agency’s Heliophysics Division, and NASA’s Launch Services Program manages launch services.
Science and industry impact
By combining ENA imaging, in situ particle measurements, dust composition analyses, and magnetic field and electron observations, IMAP aims to refine models of the heliosphere’s structure and particle acceleration. The upstream measurements from L1 support more actionable space-weather forecasting, informing spacecraft anomaly response plans, protecting crewed missions, and aiding operators across commercial, civil, and defense space sectors during periods of elevated solar activity.
Source: NASA: IMAP suite of instruments
