The Sun is an energetic star, constantly radiating energy and pumping streams of charged particles out into space. And while this solar wind can be dangerous in itself, without it, Earth and all the other members of our planetary system would be at constant risk of threats from outer space. Our host star creates a protective bubble called the heliosphere that extends far beyond the orbit of Neptune, shielding the planets from the interstellar medium. Yet though we may owe our existence to this bubble, scientists know relatively little about it.
That may be about to change: NASA is preparing a brand new mission that will travel 1 million miles away from Earth in order to map the boundaries of the heliosphere, offering clues to scientists about the exact nature of the celestial domain that we call home.
Set to launch on September 23, NASA’s Interstellar Mapping and Acceleration Probe, or IMAP, will journey to orbit the Sun at a gravitationally stable point in space known as the first Earth-Sun Lagrange Point (L1). From this unique vantage point, IMAP will gather data about the heliosphere without magnetic interference from the planets. The mission could help unlock new understanding of the drivers of space weather, and, importantly, prepare humanity for deep space exploration.
Burst my bubble
The heliosphere is a complex environment that cocoons Earth and the rest of the planets in the solar system. As charged particles emitted by the Sun sweep out into space, it creates a bubble that resembles a deflated balloon, with a rounded nose and an elongated tail. Acting as a giant shield, the heliosphere protects the planets from cosmic radiation.
IMAP, which NASA describes as a “modern-day celestial cartographer,” will map the boundary of the heliosphere and identify particles in interplanetary space. In doing so, the probe will investigate how charged particles released by the Sun interact with the space environment.
The mission builds on the pioneering Voyager spacecrafts, the first human-made objects to cross the boundary of the heliosphere and venture into interstellar space.
“With IMAP, we’ll push forward the boundaries of knowledge and understanding of our place not only in the solar system, but our place in the galaxy as a whole,” said Patrick Koehn, IMAP program scientist, in a statement. “As humanity expands and explores beyond Earth, missions like IMAP will add new pieces of the space weather puzzle that fills the space between Parker Solar Probe at the Sun and the Voyagers beyond the heliopause.”
The heliosphere explorer
IMAP is equipped with 10 instruments, all packed in a relative compact body that spans around 8-feet wide (2.4 meters) and 3-feet tall (1 meter). The spacecraft’s cylindrical structure allows it to spin at a rate of about 4 revolutions per minute, with different sections on the side for its various instruments and a top deck with solar arrays and magnetometers.
Of its 10 instruments, three are designed to collect energetic neutral atoms. These atoms begin life as positively charged particles released by the Sun, but they collide into other particles in space as they race across the solar system. As they collide, some of the positively charged particles lose their charge, thereby becoming an energetic neutral atom.
By collecting energetic neutral atoms, IMAP may be able to trace their origins and build maps of the heliosphere’s boundaries. “IMAP will advance our understanding of two fundamental questions of how particles are energized and transported throughout the heliosphere and how the heliosphere itself interacts with our galaxy,” said Shri Kanekal, IMAP mission scientist, in a statement.
The mission will also collect near real-time observations of the solar wind and energetic solar particles, which can sometimes affect Earth and spacecraft in orbit around the planet. In that sense, IMAP could help warn us if dangerous space weather is headed our way within a 30-minute timeframe. “The IMAP mission will provide very important information for deep space travel, where astronauts will be directly exposed to the dangers of the solar wind,” said David McComas, IMAP principal investigator at Princeton University, in a statement.
IMAP is also designed to measure the interstellar dust, which is made up of clumps of tiny particles and which acts as the building blocks for stars and planets. In doing so, the mission will help scientists better understand what makes up the stars and materials found outside our solar system.