A month before reaching its planned orbit, NASA announced that the Interstellar Mapping and Acceleration Probe (IMAP) has started collecting scientific data from all 10 of its instruments. The mission is led by Princeton University astrophysicist David McComas, who serves as principal investigator and professor of astrophysical sciences.
The IMAP project brings together a large team, including 82 partners across 35 U.S. states and collaborators from the United Kingdom, Poland, Switzerland, Germany, and Japan. The spacecraft was launched from Cape Canaveral on September 24, 2025.
“It’s gone even better than I dared hope,” said McComas. “Truly outstanding!”
IMAP carries ten specialized instruments designed to investigate fundamental questions about space in the solar neighborhood. Over recent months, mission scientists have activated each instrument in a specific sequence.
Jamie Rankin, another Princeton astrophysicist and co-investigator for IMAP, leads the Solar Wind and Pickup Ion instrument (SWAPI), which was constructed at Princeton. “When SWAPI turned on just over a month ago, it was in a beautiful, steady solar wind that gave us a perfectly smooth baseline to calibrate and make sure everything was functioning well. We’ve been operating in science mode ever since,” said Rankin. “It turns out that was the calm before the storm, because four days later, a powerful coronal mass ejection collided with Earth’s magnetosphere and made the aurora visible in Princeton and even down to Florida. This event was seen by IMAP ahead of time and SWAPI captured it beautifully!”
To study the boundaries of the heliosphere—the region surrounding our solar system—IMAP uses three instruments to measure energetic neutral atoms (ENAs): IMAP-Lo, IMAP-Hi, and IMAP-Ultra. These ENAs are produced at the edge of the heliosphere and allow remote study of this boundary region.
“It’s just astounding that we already have such good ENA data covered collectively by the three imagers,” said McComas. “This plus excellent first light data from all seven of the other instruments makes for a 10 out of 10, A-plus start to the mission.”
Although IMAP’s official science phase begins February 1 after entering orbit around the first Lagrange point (L1)—a location about one million miles toward the Sun from Earth—the probe has already collected significant measurements with each instrument. According to McComas, early findings may hint at new scientific mysteries for further investigation during its mission.
“The rest of the IMAP team and I are just ecstatic about where we are at,” said McComas. “It’s an incredible joy to be seeing our first scientific data and embarking on the discovery of new things.”
Once at L1, IMAP will maintain a stable orbit between Earth and Sun as it continues its observations.
