NASA’s Imap probe – Interstellar Mapping and Acceleration Probe – has just passed the Critical Design Review (CDR), a crucial step before construction can begin. Launch planned for 2025.
The planets of the solar system orbit our sun, but this is not their only interaction with it. We have long underestimated the role of the solar wind, that stream of particles ejected from the Sun that spreads in all directions in our system. It has become important to understand the processes that animate it within the heliosphere, our star’s zone of influence.
NASA has launched the Solar Terrestrial Probes (STP) program to study and predict these phenomena and their impact on a planet’s habitability and even their consequences for our civilization. The program already includes four probes deployed between 2001 and 2015 to study coronal mass ejections (CME), solar corona heating processes and interactions between the solar wind and the Earth’s magnetosphere, mesosphere and thermosphere. The IMAP mission complements the studies by focusing on the limits of our solar system.
The echo of the heliosphere
How does the solar wind behave when it reaches our limits? It should fade at the edge of the heliosphere and have no effect beyond that. How does this solar wind interact with the regions there? Which echoes do we perceive? Imap’s mission is to help us understand these processes to complement the studies conducted in regions near the Sun and within Earth orbit.
Imap will have ten scientific instruments, including three detectors for neutral atoms from the heliosheath, the outer heliosphere, or a magnetometer consisting of two detectors mounted at the end of a 1.8 m pole and measuring the direction and type of interstellar show particles. One instrument will observe the distribution of electrons transported in the solar wind, another that of hydrogen and helium ions from the solar wind and the interstellar medium. Another instrument will map the distribution of interstellar dust near us.
These instruments will help scientists map and study the composition of the interstellar medium near our system and how the solar wind interacts in these regions.
Departure 2025
The critical design review, an essential audit to give the go-ahead for the mission’s construction phase, follows other CDRs created specifically for various subsystems and scientific instruments. After these initial checks, construction of some components has already begun, according to NASA. The large number of instruments on board requires a strict timetable for the launch in 2025.
Imap will not follow the route of the Pioneer or Voyager probes for a long journey of several decades and eventually out of our solar system. In order to map the surroundings of our heliosphere, the probe will be placed at the Lagrange point L1 of the Earth-Sun system and rotated on its own axis. At this location, the study of the solar wind is not hampered by interactions with the Earth’s magnetosphere. The mission there should last at least two years and will be controlled from the Goddard Space Center.