A New View of the Heliosphere: Inside NASA’s IMAP Mission

NASA’s Interstellar Mapping and Acceleration Probe (“IMAP”) mission will help scientists better understand the heliosphere, the vast bubble of charged particles created by the Sun that shields the solar system from much of the Milky Way’s cosmic radiation. IMAP will study how the Sun generates solar wind and how that wind interacts with interstellar space at the heliosphere’s distant boundary.

Researchers have explored the heliosphere for decades through missions such as Mariner 2, which first confirmed the existence of solar wind in 1962, and Voyager 1 and Voyager 2, which crossed the heliosphere’s boundary in 2012 and 2018. The Interstellar Boundary Explorer (“IBEX”) has also mapped the region. IMAP will build on these efforts with instruments capable of producing images up to 30 times more detailed than previous missions.

After a three-month journey to an orbit about two million kilometers from Earth, IMAP will begin observing solar wind and particles streaming from the Sun. It will also study the heliosphere’s outer boundary, located roughly six to nine billion kilometers away, and collect data from interstellar space beyond it.

A key objective is measuring energetic neutral atoms (ENAs), particles that travel in straight lines because they are unaffected by magnetic fields. By tracing ENAs back to their origins, scientists can map otherwise invisible regions of the heliosphere and create the most detailed picture of it yet.

According to IMAP Principal Investigator David McComas, the mission will reveal how the heliosphere works as a protective shield around our solar system, providing new insights into one of Earth’s primary defenses against the harsh conditions of interstellar space.