NASA’s Interstellar Mapping and Acceleration Probe Passes Key Decision Point-D

The Interstellar Mapping and Acceleration Probe (IMAP) has successfully completed Key Decision Point D (KDP-D). This milestone allows the mission to move from development and design to the assembly, testing, and integration phase. IMAP’s planned launch date, which was no earlier than February 2025, was also reevaluated during the KDP-D and was moved to a target launch window from late April to late May 2025 to ensure that the project team has adequate resources to address risks and technical complexities during system integration and testing.

An illustration shows the IMAP spacecraft in the foreground in front of Earth. Scientific measurements represented in green, yellow, and red appeared overlaid on and next to Earth.
IMAP will study the protective magnetic bubble that surrounds our solar system, called the heliosphere. Credits: NASA/Princeton/Johns Hopkins APL/Josh Diaz

IMAP will function as a modern-day cartographer and will help us understand what happens when the solar wind (a constant stream of particles from the Sun) collides with materials from interstellar space. This will help researchers map the boundary of the heliosphere, the magnetic bubble created by the solar wind, and better understand how this magnetic bubble protects Earth from large amounts of harmful cosmic radiation. IMAP will be positioned about one million miles from Earth, and its instruments will collect and study the particles that make it through the heliosphere. 

Principal investigator and Princeton University professor David McComas leads the IMAP mission, which has an international team of more than 20 partner institutions. Johns Hopkins Applied Physics Laboratory (APL) is managing the development phase, is building the spacecraft, and will operate the mission. IMAP is the fifth mission in NASA’s Solar Terrestrial Probes (STP) Program portfolio. The Explorers and Heliophysics Projects Division at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the STP Program for the agency’s Heliophysics Division of NASA’s Science Mission Directorate.

The public can watch the spacecraft come together in real time via a live feed from APL’s clean room, which is now available to watch at any time on the IMAP mission website. Viewers can watch the continuous stream to see exactly how IMAP develops from a bare-bones structure to a complex, fully operational spacecraft.

Four people in white suits and masks are in a white clean room, three are standing and looking at a piece of equipment covered in various wiring. The fourth person is kneeling and working next to the equipment.The mechanical team is preparing to install the Medium Gain Antenna on the IMAP spacecraft. Credits: NASA/Johns Hopkins APL/Princeton/Ed Whitman