Voyager 2 provides a treasure of data 42 years after takeoff

Artist's impression of a Voyager probe, billions of kilometers away

With its five instruments still active, the Voyager 2 spacecraft, launched in 1977, patiently transmits its data after the passage of the "solar boundary", the heliopause, a year ago. The precious records document the area for the second time ...

Just a year ago on November 5, Voyager 2 crossed the boundary of the heliosphere, the area in which the solar winds of our star are predominant, and reached the heliopause. The flux of particles (the plasma, very sparse) in which it evolves has changed as well as the measurements of the magnetic field to which it is subjected.

After Voyager 1 in 2012, it became only the second active probe to be able to measure out of the solar "bubble" ... NASA, in a controversial vocabulary, even speaks of interstellar space. Regardless of the name, the scientific teams have enthusiastically seized the opportunity to exploit this data, despite the 16:30 journey that the statements cross between the vehicle and our planet. This Monday, they published 5 articles in Nature Astronomy.

Take an interstellar wind

Even if it is still physically in the Solar System, the Voyager 2 probe is no longer impacted by solar winds. Its sensors have measured changes in the plasmas in which it evolves, with particles charged with many other stars and cosmic rays from extreme events such as supernovae.

Of these 5 articles, which correspond to the 5 instruments of Voyager 2 still active (MAG magnetic field sensor, two sensors to detect low-energy particles LECP and CRS, and two sensors to study the plasma PLS and PWS), the main findings established by Voyager 1 are confirmed, with more precision because the PLS instrument is down on the latter.

So far from you, Sun

However, there are some differences in the measurements, in particular, because the trajectories of Voyager 1 (currently 22.1 billion km) and Voyager 2 (18.3 billion km) did not follow the same course. Voyager 1 has gone through the heliopause in the same global direction as the Sun's movement in our galaxy, which has also resulted in different plasmas. And the Sun, between 2012 and today, is not in the same "season" of its business cycle.

Stamatios Krimigis, one of the mission's original scientists and researchers at Johns Hopkins University, said that we still knew very little about the physics of heliopause, despite these two visits. " It is an entire bubble, which we crossed only at two distinct points. Unfortunately, no other mission should cross it by being active soon (New Horizons will be extinct before), and in the heat of short the two Voyager probes should slowly go out in the next 5 years ... After more than 45 years of discoveries!

Source: NASA