So far, only five spacecraft have managed to escape the Sun’s gravity field to travel into interstellar space: Pioneer 10 and 11, Voyagers 1 and 2, and New Horizons. Voyager 1 and 2 launched in 1977 and still operate at the edges of the heliosphere – the bubble that encompasses our solar system and is affected by the solar wind – while New Horizons has explored the Pluto system and other objects in the belt. of Kuiper.
Now, NASA and its partners are preparing yet another more ambitious mission: the Interstellar Probe will go much further into interstellar space with the goal of learning much more about the formation of our local heliosphere and its evolution. “This will lead to a new and inspiring exploration, which will help us understand our home in the galaxy and will represent humanity’s first deliberate step towards the space ocean that exists between our sun and other potentially habitable systems,” explains the project website. .
“The interstellar probe will go into unknown local interstellar space, where humanity has never been before,” says Elena Provornikova, heliophysics leader for the interstellar probe at the Johns Hopkins Applied Physics Laboratory (APL) in Maryland. ” For the first time, we will take a picture of our heliosphere from the outside to see what our home looks like in the solar system .” The mission plans to “image” our heliosphere using energetic neutral atoms, and perhaps even “observe the extragalactic background light from the early days of our galaxy’s formation, something that cannot be seen from Earth,” explains Provornikova. Scientists also hope to learn more about how our sun interacts with the local galaxy, which could offer clues to how other stars in the galaxy interact with their interstellar neighborhoods.
Understand the future of the Earth
The heliosphere is also important because it protects our solar system from high-energy galactic cosmic rays. The sun travels through our galaxy, passing through different regions in interstellar space, and is currently in what is called the local interstellar cloud, but recent research suggests that the sun could be moving towards the edge of the cloud, and then enter. in the next region of interstellar space, about which we know nothing. The consequences of this change are totally unknown: our heliosphere could grow, decrease, or the amount of galactic cosmic rays that enter and contribute to the level of background radiation on Earth could be modified, explains the researcher.
When will the launch be?
The project managers explain that the launch of the Interstellar Probe mission will be technologically possible in the 2030s and will take about 15 years to reach the limit of the heliosphere , a considerable speed compared to the Voyagers, which took 35 years to arrive. With the current design, the mission is expected to last at least 50 years.
Like any interstellar spacecraft, the probe will need to be autonomous, compact and lightweight, yet robust enough to be able to collect data and communicate with operators on Earth. The engineering team is using New Horizons as a base design from which to make improvements. As with the Pioneers, Voyagers and New Horizons, the reference power source will be a radioisotope thermoelectric generator, which will provide power for this long-duration mission that will travel great distances from the Sun.
