NASA’s Voyager 1 spacecraft is nearing the edge of our solar system, where the intensity of charged particles from beyond our solar system is markedly increased. The voyager scientists who are studying this rapid rise think that Voyager 1 is very close to exiting out of solar system, which will make it the first man-made object to make it into interstellar space.
“The laws of physics say that someday Voyager will become the first human-made object to enter interstellar space, but we still do not know exactly when that someday will be,” said Ed Stone, Voyager project scientist at the California Institute of Technology in Pasadena. “The latest data indicate that we are clearly in a new region where things are changing more quickly. It is very exciting. We are approaching the solar system’s frontier.”
“The data making the 16-hour-38 minute, 11.1-billion-mile (17.8-billion-kilometer), journey from Voyager 1 to antennas of NASA’s Deep Space Network on Earth detail the number of charged particles measured by the two High Energy telescopes aboard the 34-year-old spacecraft.” These charged particles are generated when stars in our cosmic neighborhood go supernova.
“From January 2009 to January 2012, there had been a gradual increase of about 25 percent in the amount of galactic cosmic rays Voyager was encountering,” said Stone. “More recently, we have seen very rapid escalation in that part of the energy spectrum. Beginning on May 7, the cosmic ray hits have increased five percent in a week and nine percent in a month.”
This rapid increase is one of three different data sets that need to see significant increases to indicate the beginning of interstellar space. The next indication from the spacecraft’s two telescopes is the intensity of the energetic particles generated inside the heliosphere, the bubble of charged particles the sun blows around itself. There has been a slow decline in the measurements of these particles, but they have yet to drop off precipitously, which is expected to happen when Voyager breaks through the solar boundary.
The last data set that the Voyager scientists are looking for is the measurement in the direction of the magnetic field lines surrounding the spacecraft. When Voyager is still within the heliosphere, these field lines run east-west. When it passes into interstellar space, the team expects Voyager will find that the magnetic field lines orient in a more north-south direction. Analyzing this change will take weeks though, and the Voyager team is still analyzing the numbers of its latest data set.
“When the Voyagers launched in 1977, the space age was all of 20 years old,” said Stone. “Many of us on the team dreamed of reaching interstellar space, but we really had no way of knowing how long a journey it would be — or if these two vehicles that we invested so much time and energy in would operate long enough to reach it.”
Voyager 1 and 2 were launched in 1977 and are still working well. Voyager 2 is more than 9.1 billion miles (14.7 billion kilometers) away from the sun. Both of the spacecraft are operating as part of the Voyager Interstellar Mission, which is an extended mission to explore the solar system outside of the outer planets and beyond that. NASA’s Voyagers are the two most-distant man-made objects.
The Voyager spacecraft were both built by NASA’s Jet Propulsion Laboratory in Pasadena, Calif., which continues to operate both. JPL is a division of the California Institute of Technology. The Voyager missions are a part of the NASA Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate in Washington.
“The twin Voyager 1 and 2 spacecraft continue exploring where nothing from Earth has flown before. In the 34th year after their 1977 launches, they each are much farther away from Earth and the Sun than Pluto. Voyager 1 and 2 are now in the “Heliosheath” – the outermost layer of the heliosphere where the solar wind is slowed by the pressure of interstellar gas. Both spacecraft are still sending scientific information about their surroundings through the Deep Space Network (DSN).”
“The primary mission was the exploration of Jupiter and Saturn. After making a string of discoveries there — such as active volcanoes on Jupiter’s moon Io and intricacies of Saturn’s rings — the mission was extended. Voyager 2 went on to explore Uranus and Neptune, and is still the only spacecraft to have visited those outer planets. The adventurers’ current mission, the Voyager Interstellar Mission (VIM), will explore the outermost edge of the Sun’s domain. And beyond.”
Image Credits: NASA/JPL-Caltech