Image: Artist’s impression of the Interstellar Mapping and Acceleration Probe (IMAP). Credit: NASA/Johns Hopkins APL/Princeton University/Steve Gribben.

By Burt Dicht
NSS Managing Director of Membership

Surrounding our solar system is a vast, invisible bubble—a protective frontier often unnoticed outside scientific circles. It is called the heliosphere. Born from the solar wind, a continuous stream of charged particles from the Sun, this bubble stretches far beyond Pluto’s orbit. Without it, Earth would be bathed in dangerous cosmic radiation from the galaxy beyond. The heliosphere is not just a boundary; it is our first line of defense against the harshness of interstellar space. 

Understanding this protective bubble is the goal of NASA’s Interstellar Mapping and Acceleration Probe (IMAP) mission.

Launched today at 7:30 a.m. EDT, just 18 minutes after sunrise, IMAP lifted off aboard a SpaceX Falcon 9 from Kennedy Space Center’s historic LC-39A. The spacecraft is now on its way to the first Sun–Earth Lagrange point (L1), one million miles from Earth. There it will study the solar wind, cosmic rays, and the frontier where the solar system meets interstellar space. By doing so, IMAP will help scientists uncover how the heliosphere works, how it shields us, and how energetic particles are accelerated across the cosmos.

IMAP is not traveling alone. Thanks to SpaceX’s rideshare program, it launched alongside two other spacecraft: the NASA Carruthers Geocorona Observatory (CGO) and the National Oceanic and Atmospheric Administration (NOAA) Space Weather Follow On-Lagrange 1 (SWFO-L1) spacecraft. Together, they represent a coordinated effort to deepen our understanding of space weather—the dynamic flow of particles and fields streaming from the Sun. This is not just an academic pursuit. Space weather can disrupt satellites, damage spacecraft electronics, endanger astronauts, and even trigger power grid failures and communication blackouts on Earth.

At the heart of IMAP is a suite of 10 instruments, designed to observe particles, electromagnetic fields, and ultraviolet light across a vast range of energies. The mission is led by Princeton University professor Dr. David J. McComas, working with an international team from 25 partner institutions. The spacecraft was built by the Johns Hopkins Applied Physics Laboratory, and IMAP is the fifth mission in NASA’s Solar Terrestrial Probes (STP) Program.

But missions like IMAP are not just built from technology; they are built from people—people whose own journeys shaped their role in exploring the Sun. I had the opportunity to speak with two of them: Dr. Michele Cash, IMAP’s deputy program scientist at NASA Headquarters, and Dr. Jamie Rankin, instrument lead for IMAP’s Solar Wind and Pickup Ion (SWAPI) investigation at Princeton University. Their stories highlight the human inspiration behind this cutting-edge mission.

For Dr. Cash, that inspiration began as a student reading a biography of astronaut Sally Ride. That spark led her to Stanford University to study space physics and astrobiology, developing a deep interest in planetary habitability, geomagnetic storms, and space weather. Before joining NASA, she spent 12 years at NOAA’s Space Weather Prediction Center. Now, her focus is on heliophysics and the Sun’s influence on Earth and beyond. She emphasized that IMAP will provide a new window into how the solar wind interacts with the edge of the heliosphere, shaping the environment in which our planet—and our technology—must operate.

Dr. Rankin’s journey began in Utah, where visits to observatories fueled her fascination with high-energy particles. She carried that passion to Caltech, where she helped build and calibrate the Energetic Particle Instrument – High Energy (EPI-Hi), now flying through the Sun’s corona aboard the Parker Solar Probe. There she met legendary Voyager project scientist and former JPL director Ed Stone, who hadn’t taken a graduate student in 25 years until bringing her into his lab. She later became one of NASA’s youngest-ever deputy project scientists, stepping into a leadership role with Voyager as the mission entered its historic interstellar phase.

It was also at Caltech where Rankin first met IMAP mission leader McComas, who saw her potential and invited her to join his Princeton research team. On IMAP, she serves as the instrument lead for SWAPI—the Solar Wind and Pickup Ion instrument—which will measure the speed, density, and composition of particles streaming outward from the Sun. SWAPI will also detect pickup ions—atoms from interstellar space that drift into our solar system, become ionized, and are swept up by the solar wind. Tracking these particles helps scientists understand how the solar wind evolves as it travels through space and how the heliosphere interacts with the galaxy beyond.

For Rankin, IMAP is an opportunity to answer fundamental questions: How is the solar wind accelerated? How does it evolve as it travels through space? And how do those changes ripple through our solar neighborhood? She underscored that every spacecraft on this launch—not just IMAP—adds to the larger picture of how the Sun influences space, knowledge that is essential as humanity grows more reliant on satellites and looks toward deeper exploration.

The heliosphere may be invisible, but its influence is everywhere. It is our shield, our filter, and our frontier. By probing its mysteries, IMAP and its companions will help scientists better predict and mitigate the effects of space weather—protecting satellites, astronauts, and the power grids and communication systems we depend on daily.

As Dr. Cash and Dr. Rankin reminded me, this mission is more than science. It is about understanding how our Sun shapes the environment we live in and ensuring humanity can thrive both on Earth and in space. They also offered advice to students who want to follow in their path. Dr. Cash noted that careers are rarely linear and urged, “follow your passions.” Dr. Rankin’s guidance was simple but powerful: always ask questions and “stay curious.”

IMAP’s mission is ultimately about advancing our ability to understand and predict space weather. By revealing how the solar wind and cosmic particles shape the heliosphere, IMAP will give us the tools to better protect satellites, astronauts, and the infrastructure we rely on every day. Each new discovery strengthens our readiness for the future—helping us safeguard life on Earth while preparing for journeys to the Moon, Mars, and beyond. As of this writing, all three spacecraft are in route to L1 and communicating with their mission controllers—a promising start to a journey that will reshape our understanding of the heliosphere and its influence on Earth.