Voyager 1, the spacecraft launched by the United States in 1977, may cross the boundary of the Solar System at any time in the near future.
>>> Humans Are About to Leave the Solar System
Data from Voyager 1’s instruments indicate a significant increase in the number of charged particle streams colliding with the spacecraft. This is a sign that Voyager 1 will soon enter interstellar space—the most important mission of its journey.
“One day soon, Voyager 1 will become the first human-made object to enter interstellar space, but we do not yet know the exact date when the spacecraft will achieve this milestone,” stated Ed Stone, a scientist at the California Institute of Technology in the United States.
Illustration of Voyager 1 exploring Saturn before heading towards the center of the Milky Way.
Voyager 1 is traveling at a speed of 17 km/s and is currently approximately 18 billion kilometers away from Earth. At this distance, signals from the spacecraft take about 16.5 hours to reach Earth.
For the past three years, Voyager 1 has been using its instruments to explore the “heliosheath” in space. This region contains high-energy particles from the Sun and interstellar space. Charged particles escape the Sun’s surface at speeds of up to 1.7 million km/h; however, upon reaching the “heliosheath”, their velocity decreases significantly. Measurements from the instruments indicate that the number of charged particle streams colliding with the spacecraft has been gradually increasing over the past three years, with a sudden spike in the number of streams observed last month.
The number of charged particle streams is one of three indicators that NASA uses to estimate when the spacecraft will cross the boundary of the Solar System. A substantial increase in the number of particle streams signifies that the spacecraft is approaching interstellar space.
Voyager 1 was launched on September 5, 1977. Its counterpart, Voyager 2, was launched into space on August 20 of the same year. The initial mission of both spacecraft was to explore Jupiter, Saturn, Uranus, and Neptune, which they completed in 1989.
Afterward, they continued their journey toward the center of the Milky Way in two different directions. Their nuclear reactors are expected to cease power production in about 10 to 15 years. Once the reactors shut down, the electronic and broadcasting instruments of both spacecraft will become inoperative.
