NASA’s Voyager 1 spacecraft may be getting its first taste of interstellar waters beyond our sun’s familiar shores and, like the pioneers that first took to the oceans to explore seas unknown, the 34-year-old robotic spacecraft is about to make history as the first man-made object to venture beyond the known horizon.
This historic announcement was made on Thursday by the team keeping a careful eye on Voyager 1′s particle detectors who noticed an uptick in interstellar cosmic ray counts in recent years. That can mean only one thing: the mission is beginning to leave the outermost regions of the heliosphere — the farthest extent of the sun’s influence.
“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,” said Ed Stone, Voyager project scientist at Caltech in Pasadena, Calif.
“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,” he continued. “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.”
Complementing the detection of the uptick of interstellar cosmic rays, another detector has watched a marked decline in the quantity of energetic particles emanating from within the heliosphere. When the spacecraft completely exits the sun’s sphere of influence, this particle count will disappear.
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To emphasize the rapid changes in the high energy environment surrounding Voyager 1, the Voyager 2 Twitter feed on Wednesday reported about the well-being of its sister craft:
Interesting. Compare my data 4 high-energy nucleons
The final measure will ultimately be the detection of a shift in magnetic field orientation. Currently, Voyager 1 is still “feeling” the magnetic influence of the sun, but once the probe flies beyond the boundary — called the heliopause — a radical change in magnetic field orientation is expected.
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Data from Voyager 1 is currently taking 16-hours and 38 minutes to travel from the spacecraft’s antennae, through 11.1 billion miles (17.8 billion kilometers) of space and to NASA’s Deep Space Network on Earth.
Voyager 1 and her twin Voyager 2 were launched in 1977 to explore the outermost planets and, ultimately, interstellar space. They both remain operational to this day, feeding mission scientists with invaluable data about the environment of the “final frontier” of the sun’s influence.
Curious discoveries have been made in this mysterious region, discoveries that could have only been made by physically sending a spacecraft there.
“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.”
Not only have they operated that long, they have exceeded expectations, and if the recent measurements made by Voyager 1′s detectors are anything to go by, the spacecraft is about to make history as mankind’s first artifact to be flung into a very alien place: interstellar space.
Image: Artist’s rendering of Voyager 2 in the outer regions of the heliosphere, the magnetic bubble around the solar system generated by the solar wind (NASA)